WO2006095868A1 - Content data transmission device, content data transmission method, and remote reproduction system - Google Patents

Content data transmission device, content data transmission method, and remote reproduction system Download PDF

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Publication number
WO2006095868A1
WO2006095868A1 PCT/JP2006/304782 JP2006304782W WO2006095868A1 WO 2006095868 A1 WO2006095868 A1 WO 2006095868A1 JP 2006304782 W JP2006304782 W JP 2006304782W WO 2006095868 A1 WO2006095868 A1 WO 2006095868A1
Authority
WO
WIPO (PCT)
Prior art keywords
content data
transmission
means
data
receiving device
Prior art date
Application number
PCT/JP2006/304782
Other languages
French (fr)
Japanese (ja)
Inventor
Fumiaki Kikuchi
Kazushi Tahara
Kenji Yashiro
Tomoya Ohishi
Original Assignee
Pioneer Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to JP2005069605 priority Critical
Priority to JP2005-069605 priority
Application filed by Pioneer Corporation filed Critical Pioneer Corporation
Publication of WO2006095868A1 publication Critical patent/WO2006095868A1/en

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00Details of television systems
    • H04N5/76Television signal recording
    • H04N5/765Interface circuits between an apparatus for recording and another apparatus
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/232Content retrieval operation locally within server, e.g. reading video streams from disk arrays
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/234Processing of video elementary streams, e.g. splicing of video streams, manipulating MPEG-4 scene graphs
    • H04N21/2347Processing of video elementary streams, e.g. splicing of video streams, manipulating MPEG-4 scene graphs involving video stream encryption
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/238Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams
    • H04N21/23805Controlling the feeding rate to the network, e.g. by controlling the video pump
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/63Control signaling related to video distribution between client, server and network components; Network processes for video distribution between server and clients or between remote clients, e.g. transmitting basic layer and enhancement layers over different transmission paths, setting up a peer-to-peer communication via Internet between remote STB's; Communication protocols; Addressing
    • H04N21/637Control signals issued by the client directed to the server or network components
    • H04N21/6377Control signals issued by the client directed to the server or network components directed to server
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/65Transmission of management data between client and server
    • H04N21/658Transmission by the client directed to the server
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00Television systems
    • H04N7/16Analogue secrecy systems; Analogue subscription systems
    • H04N7/173Analogue secrecy systems; Analogue subscription systems with two-way working, e.g. subscriber sending a programme selection signal
    • H04N7/17309Transmission or handling of upstream communications
    • H04N7/17318Direct or substantially direct transmission and handling of requests
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00Details of television systems
    • H04N5/76Television signal recording
    • H04N5/78Television signal recording using magnetic recording
    • H04N5/781Television signal recording using magnetic recording on disks or drums

Abstract

Before receiving a content data transmission request transmitted from a reception device (90), a transmission device (60) decodes a transmission start portion of content data held by a hard disc drive (61), encodes the transmission start portion with an encode rate based on the communication environment, and further encrypts it. The transmission start portion of the content data which has been subjected such processes is held in a transmission start portion holding RAM (66). Thus, when a content data transmission request is received, the transmission device (60) firstly transmits the transmission start portion of the content data held in the RAM (66) to a reception device (90).

Description

 Specification

 Content data transmitting apparatus, content data transmitting method, and remote reproduction system

 Technical field

[0001] The present invention communicates with each other between a transmission device and a reception device, and transmits content data stored in the transmission device to the reception device in accordance with a remote operation from the reception device. The present invention relates to a remote reproduction system that reproduces this, a transmission device suitable for use in the remote reproduction system, and a content data transmission method.

 Background art

 [0002] Currently, AV (Audio Visual) devices and network home appliances having a function of performing information communication by connecting to a communication network such as the Internet are being developed. For example, audio and video recorders equipped with information communication functions are being developed. On the other hand, mobile terminals equipped with a function for performing information communication by connecting to a mobile communication network such as a mobile phone network or a wireless local area network (LAN) have become widespread. For example, mobile phones, PDAs (Personal Digital Assistance), car navigation devices, and mopile personal computers are widely used.

 [0003] As mobile terminals have become widespread in this way and AV devices having information communication functions are being developed, development of a remote playback system is in progress. Remote playback systems generally perform wireless communication between a transmitting device such as an AV device and a receiving device such as a mobile terminal, transmit content data such as music or movies, and other information to the receiving device and receive them. When the information is replayed on the device, it is a system. According to the remote playback system, the user can easily view music or movies outdoors.

[0004] Streaming is planned to be adopted in the remote reproduction system. According to the remote reproduction system employing streaming, the transmission device transmits content data to the reception device, and the reception device immediately reproduces the content data while receiving the content data. According to such a remote playback system, the user can enjoy music or video outdoors as shown below. You will be able to view the pictures even more easily. For example, a hard disk having a large recording capacity is provided in the transmission device, and movie content data for a long time is recorded on this hard disk. A user who is outdoors operates the receiving device and requests the transmitting device to transmit movie content data recorded on the hard disk of the transmitting device. In response to this, the transmission device transmits the movie content data recorded on the hard disk to the reception device. The receiving device includes a buffer memory having a small recording capacity. The receiving device receives the movie content data transmitted by the transmitting device, and immediately reproduces it while storing it in the buffer memory. The receiving device is provided with a liquid crystal display, for example, and the reproduced movie content data is displayed on the liquid crystal display. The receiving device only has a communication interface, a decoder, a small memory capacity of a memory memory, a simple operation panel, a liquid crystal display, etc. Therefore, it is small in size, light in weight and low in power consumption. According to the remote playback system, a user can enjoy a long movie easily outdoors by using a portable and easy-to-handle receiving device.

Disclosure of the invention

Problems to be solved by the invention

By the way, in the remote reproduction system, it is planned that the user takes the receiving device outdoors and watches movies or music outdoors. There are various outdoor communication environments. For example, the communication environment differs greatly when the receiver is in a large park and between buildings. Therefore, one of the development goals of the remote playback system is to maintain good transmission of content data in various communication environments and to always achieve stable playback. As one means for achieving this goal, there is a technology for encoding content data at an encoding rate according to the quality of the communication environment in the transmitting device and transmitting the encoded content data to the receiving device. Has been developed. For example, when the communication environment is good, the transmission device increases the encoding rate and transmits content data with a low compression rate to the reception device. In this case, the amount of content data transmitted from the transmission device to the reception device increases. As a result, although the quality of the video reproduced in the receiving device is enhanced, it is difficult to transmit the content data to the receiving device without error. I will be. However, when the communication environment is good, such a transmission often works well. On the other hand, when the communication environment is bad, the transmitting device lowers the encoding rate and transmits content data with a high compression rate to the receiving device. In this case, the amount of content data transmitted from the transmitting device to the receiving device is reduced. As a result, although the quality of the image reproduced in the receiving device is lowered, it becomes easy to transmit the content data to the receiving device without any error. Therefore, even if the communication environment is bad, transmission will be successful.

 [0006] In a remote reproduction system that employs such a technique, content data is encoded at an encoding rate according to the communication environment before the transmission device transmits content data to the reception device. If the transmitting device receives a request for transmitting content data, encodes the content data to be transmitted, and then transmits this content data to the receiving device, the transmitting device The time from when the content data transmission request is received from the receiving device until the actual transmission of the content data starts is increased by the time for executing the encoding. This extension of time appears as a delay from when the user performs an operation to start playback of content data to when playback of content data actually starts. Such a delay may cause undesirable problems such as making the user feel unresponsive.

[0007] On the other hand, in a remote reproduction system, content data such as a movie or music protected by copyright may be transmitted from a transmission device to a reception device. In some cases, users send content data that they want to keep secret. If a public network such as the Internet or a cellular phone network is used as the communication network between the transmitting device and the receiving device, content data may be intercepted by others. If such a risk is left unattended, copyright protection is eroded or the user cannot keep secret. Therefore, another development goal for remote playback systems is to increase the confidentiality of content data. As one means for achieving this goal, a technology has been developed in which the content data is encrypted in the transmission device and the encrypted content data is transmitted to the reception device.

[0008] In a remote reproduction system employing such a technique, the content data is encrypted before the transmission device transmits the content data to the reception device. If the transmitter is a receiver After receiving the request for transmitting content data, the content data to be transmitted is encrypted, and then the content data is transmitted to the receiving device. The time from when the data transmission request is received until the actual transmission of the content data is started is increased by the time for executing the encryption key. This extension of time appears as a delay from when the user performs an operation for starting the reproduction of content data until the actual reproduction of the content data is started. Such a delay may cause a favorable habit problem, such as making the user feel inoperable or annoying.

 [0009] A similar problem is that content data recorded on the hard disk of the transmission device is encrypted in advance, and the content data needs to be decrypted before the transmission device transmits the content data to the reception device. It can happen in some cases. Also, this problem is that the content data recorded on the hard disk of the transmission device is compressed in advance, and the content data needs to be expanded (decompressed) before the transmission device transmits the content data to the reception device. It can also happen.

 [0010] The present invention has been made in view of the problems exemplified above, and the first problem of the present invention is that the response is excellent, the operability is excellent, and the user does not feel troublesome operation. The object is to provide a transmission device, a remote reproduction system, a content data transmission method, and a computer program.

 [0011] A second problem of the present invention is that a user can perform an operation to start the reproduction of content data and can shorten the time until the actual reproduction of content data is started. It is to provide a system, a content data transmission method, and a computer program.

 [0012] A third problem of the present invention is that a transmission device, a remote reproduction system, and a content that can shorten the time from when the transmission device receives a content data transmission request until the transmission of content data is started. It is to provide a data transmission method and a computer program.

 Means for solving the problem

[0013] In order to solve the above problems, a first transmission device of the present invention is a content in a reception device. A transmitting device for transmitting the content data to the receiving device in response to a content data transmission request transmitted from the receiving device in order to reproduce the data by streaming; and a first data holding means for holding the content data The first data holding during a transmission waiting period included in a period from when it becomes possible to encode the content data held by the first data holding means to when the content data transmission request is received Encoding means for encoding the transmission start part of the content data held by the means, second data holding means for holding the transmission start part of the content data encoded by the encoder means, and transmitted from the receiving device Receiving means for receiving a content data transmission request; And a transmission means for transmitting the transmission start portion of the content data held by the second data holding means to the receiving device when the content data transmission request is received by the receiving means.

 In order to solve the above problem, a first remote reproduction system of the present invention includes a transmission device and a reception device connected to each other via a network, and responds to a content data transmission request transmitted from the reception device. In response, the transmission device transmits content data to the reception device, and the reception device reproduces the content data by streaming, wherein the transmission device holds a first data holding content data. And a power at which the content data held by the first data holding means can be encoded during the transmission standby period included in a period until the content data transmission request is received. (1) Encoding means for encoding the transmission start part of the content data held by the data holding means; Second data holding means for holding a transmission start portion of the content data encoded by the encoder means, receiving means for receiving the content data transmission request transmitted by the receiving device, and the content data by the receiving means. When a transmission request is received, there is provided transmission means for transmitting the transmission start portion of the content data held by the second data holding means to the receiving device.

[0015] In order to solve the above-described problem, a first content data transmission method according to the present invention provides a receiving device that reproduces content data by streaming from the receiving device. A content data transmission method in a transmission device for transmitting the content data to the reception device in response to a transmitted content data transmission request, wherein content data held in a first data holding unit can be encoded The first encoding that encodes the transmission start part of the content data held in the first data holding unit during the transmission waiting period included in the period until the content data transmission request is received. And a data holding step for holding a transmission start portion of the content data encoded in the first encoding step in a second data holding unit, and when the content data transmission request is received, the second data holding unit The first transmitter that transmits the transmission start portion of the content data held in the receiver to the receiver. It is equipped with a door.

 [0016] In order to solve the above-described problem, the second transmission device of the present invention transmits the content data in response to a content data transmission request transmitted from the reception device in order to reproduce the content data by streaming in the reception device. A transmitting device for transmitting to the receiving device, the first data holding means for holding content data, and the time when it becomes possible to encrypt the content data held by the first data holding means An encryption unit for encrypting a transmission start portion of the content data held by the first data holding unit during a transmission waiting period included in a period until a content data transmission request is received; and the encryption Second data holding means for holding a transmission start portion of the content data encrypted by the means, and the receiving device Receiving means for receiving the content data transmission request sent from the receiver, and when the content data transmission request is received by the receiving means, the transmission start portion of the content data held by the second data holding means And transmitting means for transmitting to.

In order to solve the above-described problem, a second remote reproduction system of the present invention includes a transmission device and a reception device connected to each other via a network, and responds to a content data transmission request transmitted from the reception device. In response, the transmission device transmits content data to the reception device, and the reception device reproduces the content data by streaming, wherein the transmission device holds a first data holding content data. And the content data held by the first data holding means Power to be able to encrypt Encrypt the transmission start portion of the content data held by the first data holding means during the transmission waiting period included in the period until the content data transmission request is received. Encrypting means, second data holding means for holding a transmission start portion of the content data encrypted by the encrypting means, and receiving means for receiving the content data transmission request transmitted by the receiving device. And a transmission means for transmitting the transmission start portion of the content data held by the second data holding means to the receiving device when the content data transmission request is received by the receiving means.

 [0018] In order to solve the above-described problem, the second content data transmission method of the present invention provides the content in response to a content data transmission request transmitted from the receiving device in order to reproduce the content data by streaming in the receiving device. A content data transmission method in a transmission device for transmitting data to the reception device, wherein the content data held in the first data holding unit can be encrypted. An encryption step for encrypting a transmission start portion of the content data held in the first data holding unit during a transmission waiting period included in a period until reception, and the encryption step. A data holding step of holding a transmission start portion of the encrypted content data in a second data holding unit; A transmission step of transmitting a content data transmission start portion held in the second data holding unit to the receiving device when a content data transmission request is received.

[0019] In order to solve the above-described problem, the third transmitting device of the present invention uses the content data in response to a content data transmission request transmitted from the receiving device in order to reproduce the content data by streaming in the receiving device. A transmitting device for transmitting to the receiving device, the first data holding means for holding the encrypted content data, and the encrypted content data held by the first data holding means The transmission start portion of the encrypted content data held by the first data holding means during the transmission waiting period included in the period until the content data transmission request is received. A decryption means for decrypting, and a transmission start portion of the content data decrypted by the decryption means. Second data holding the equity Means, a receiving means for receiving a content data transmission request transmitted from the receiving device, and when the content data transmission request is received by the receiving means,

(2) Transmission means for transmitting a transmission start portion of the content data held by the data holding means to the receiving device.

[0020] In order to solve the above-described problem, a third remote reproduction system of the present invention includes a transmission device and a reception device connected to each other via a network, and responds to a content data transmission request transmitted from the reception device. In response, the transmitting device transmits content data to the receiving device, and the receiving device reproduces the content data by streaming, the transmitting device holding the encrypted content data The first data holding means and the power that makes it possible to decrypt the encrypted content data held by the first data holding means In the period until the content data transmission request is received The transmission start unit of the encrypted content data held by the first data holding means during the included transmission waiting period Decryption means for decrypting, second data holding means for holding a transmission start portion of the content data decrypted by the decryption means, and a content data transmission request transmitted from the receiving device. Receiving means for receiving, and when the content data transmission request is received by the receiving means, transmission means for transmitting the transmission start portion of the content data held by the second data holding means to the receiving device. ing.

[0021] In order to solve the above-described problem, the third content data transmission method of the present invention provides the content data in response to a content data transmission request transmitted from the receiving device in order to reproduce the content data by streaming in the receiving device. A content data transmission method in a transmission device for transmitting data to the reception device, wherein the encrypted content data held in the first data holding unit can be decrypted. A decryption step of decrypting a transmission start portion of the encrypted content data held in the first data holding unit during a transmission waiting period included in a period until a content data transmission request is received; The transmission start portion of the content data decrypted in the decryption step is stored in the second data storage unit. Preservation and holding step, when the content data transmission request is received, the second data holding unit A transmission step of transmitting a transmission start portion of the received content data to the receiving device.

 [0022] In order to solve the above problem, the fourth transmission device of the present invention, in order to reproduce the content data by streaming in the reception device, the content data in response to a content data transmission request transmitted from the reception device. A transmitting device that transmits to the receiving device, the first data holding unit holding compressed content data, and the compressed content data held by the first data holding unit can be expanded. A power unit for expanding a transmission start portion of the compressed content data held by the first data holding unit during a transmission waiting period included in a period until the content data transmission request is received; A second data holding means for holding a transmission start portion of the content data expanded by the expansion means And receiving means for receiving the transmitted content data request, and when the content data transmission request is received by the receiving means, the content data held by the second data holding means Transmitting means for transmitting the transmission start portion to the receiving device.

[0023] In order to solve the above problems, a fourth remote reproduction system of the present invention includes a transmission device and a reception device connected to each other via a network, and responds to a content data transmission request transmitted from the reception device. In response, the transmitting device transmits content data to the receiving device, and the receiving device reproduces the content data by streaming, wherein the transmitting device holds the compressed content data. A data holding means and a power capable of decompressing the compressed content data held by the first data holding means during a transmission waiting period included in a period until the content data transmission request is received. Next, the transmission start portion of the compressed content data held by the first data holding means is expanded. A second data holding means for holding a transmission start portion of the content data expanded by the expansion means, a receiving means for receiving the content data transmission request transmitted by the receiving device, When the content data transmission request is received by the receiving means, the transmission start portion of the content data held by the second data holding means is Transmission means for transmitting to the receiving device.

 [0024] In order to solve the above-mentioned problem, the fourth content data transmission method of the present invention provides the content in response to a content data transmission request transmitted from the receiving device in order to reproduce the content data by streaming in the receiving device. A content data transmission method in a transmission device for transmitting data to the reception device, wherein the compressed content data held in the first data holding unit can be decompressed. A decompression step of decompressing the transmission start portion of the compressed content data held in the first data holding unit during a transmission waiting period included in a period until the request is received, and decompression in the decompression step A data holding step of holding a transmission start portion of the content data received in a second data holding unit; When content data transmission request is received, and a transmission step of transmitting a transmission start portion of the content data held in the second data holding unit to the receiving device.

 [0025] In order to solve the above problems, the first to fourth computer programs of the present invention cause the computer to function as the first to fourth transmission devices of the present invention.

 [0026] In order to solve the above problems, the first to fourth computer program products in a computer-readable medium clearly embody program instructions that can be executed by a computer, and the computer is the first of the present invention. Or function as a fourth transmitter (including various modes).

 [0027] According to each computer program product of the present invention, if the computer program product is read into a computer from a recording medium such as a ROM, CD-ROM, DVD-ROM, or hard disk storing the computer program product, or For example, if the computer program product, which is a transmission wave, is downloaded to a computer via communication means, the first to fourth transmission devices of the present invention described above can be implemented relatively easily. More specifically, the computer program product includes a computer-readable code (or a computer-readable command) that functions as the first and fourth transmission devices of the present invention described above. Be composed ヽ.

[0028] These effects and other advantages of the present invention will become more apparent from the following embodiments and examples. Brief Description of Drawings

 FIG. 1 is a block diagram showing a first embodiment of a remote reproduction system of the present invention.

 2 is a block diagram showing an internal structure of the transmission device in FIG.

 FIG. 3 is a flowchart showing an operation of the transmission device in FIG. 1.

 FIG. 4 is a flowchart showing an unreproduced part detection process in FIG.

 5 is a flowchart showing an encoding rate setting process in FIG.

 FIG. 6 is an explanatory diagram showing the encoding operation and transmission operation in the transmission apparatus in FIG. 1 side by side on the time axis.

 FIG. 7 is a block diagram showing a transmission apparatus in a second embodiment of the remote reproduction system of the present invention.

 FIG. 8 is a block diagram showing a transmitting apparatus in a third embodiment of the remote reproduction system of the present invention.

 FIG. 9 is a block diagram showing a transmission apparatus in a fourth embodiment of the remote reproduction system of the present invention.

 FIG. 10 is a block diagram showing an embodiment of a remote reproduction system of the present invention.

 Explanation of symbols

[0030] 1, 100 Remote playback system

 2, 20, 30, 40, 60 Transmitter

 3, 90 receiver

 11 First data holding means

 12 Encoding means

 13 Encoding rate setting method

 14 Second data holding means

 15 Receiving means

 16 Transmission means

 17 History recording means

 18 Unreproduced part detection means

19 Switching means 21 Encryption methods

 31 Decryption means

 41 Stretching means

 62 Decryptor

 63 Decoder

 64 encoder

 65 Encryptor

 66 Transmission start part holding RAM

 67 selector

69 • ft history fep : [5

 70 Unreproduced part detector

 71 Encoding control section

 72 Transmission control unit

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the best mode for carrying out the present invention will be described for each embodiment in order with reference to the drawings.

 [0032] (First embodiment of remote reproduction system)

FIG. 1 shows a first embodiment of the remote reproduction system of the present invention. As shown in FIG. 1, the remote reproduction system 1 includes a transmission device 2 and a reception device 3. The transmission device 2 and the reception device 3 are connected to each other via the communication path 4 and communicate with each other. The transmission device 2 is preferably provided with a recording medium having a large recording capacity. This recording medium holds content data with a large data size, such as a long movie. The receiving device 3 can remotely control the transmitting device 2. When the reception device 3 transmits a content data transmission request to the transmission device 2, the transmission device 2 transmits content data to the reception device 3 in response thereto. The receiving device 3 receives the content data transmitted from the transmitting device 2 and reproduces it. Remote playback system 1 uses streaming technology. The receiving device 3 includes a nota memory, and immediately reproduces the content data while storing the received content data in the nota memory. In addition, the receiver The device 3 includes a display, for example. If the content data is video data, it is displayed on this display.

[0033] The content data is preferably video data or music data. The content data may be still image data, document data, numerical data, or audio data other than music.

 [0034] The transmission device 2 is preferably an AV device or a networked home appliance having a function of performing information communication. For example, the transmission device 2 is an audio / video recorder having an information communication function. The transmission device 2 may be a server “computer”, a personal “computer”, another computer, or various devices equipped with a computer. The transmitter 2 will be described in detail later with reference to FIG. 2 and FIG.

 [0035] The receiving device 3 (a) transmits control information such as a content data transmission request to the transmitting device 2 and receives a content data transmitted from the transmitting device 2, and (b) received The buffer device that temporarily stores content data, (c) a decoder that plays back the received content data, (d) a display that displays the playback video, and (e) an instruction to send a content data transmission request, etc. It is desirable to have an operation panel for remote operation. Note that, when content data is encrypted and transmitted as in the video playback system 2 described later, the receiving device 3 includes a decryptor that decrypts the encrypted content data. The receiving device 3 is, for example, a mobile phone, a PDA, a car navigation device or a mopile personal computer. The receiving device 3 is desirably small and has excellent portability and portability. However, the receiving device 3 may be, for example, a desktop personal computer or a telemedicine computer.

 [0036] Communication path 4 may be wired or wireless! The communication path 4 is, for example, the Internet, a computer network such as a wide area network (WAN) or a local area network (LAN), a mobile phone network, or IMT-2000 (International Mobile Telecommunications-2000). According to the example of FIG. 1, the communication path 4 is a composite communication network in which the Internet 5 and a mobile phone line are connected via a base station 6 and a gateway (not shown).

[0037] The remote reproduction system 1 responds to the good or bad communication environment between the transmission device 2 and the reception device 3. It also has a function to set and change the encoding rate of content data. For example

When the communication environment is good, the transmission device 2 increases the encoding rate and transmits content data with a low compression rate to the reception device 3. In this case, the amount of content data transmitted from the transmission device 2 to the reception device 3 increases. As a result, although the quality of the image reproduced by the receiving device 3 is improved, it becomes difficult to transmit content data from the transmitting device 2 to the receiving device 3 without error. However, when the communication environment is good, such transmissions often do not work. On the other hand, when the communication environment is bad, the transmission device 2 reduces the encoding rate and transmits content data with a high compression rate to the reception device 3. In this case, the amount of content data transmitted from the transmission device 2 to the reception device 3 is reduced. As a result, although the quality of the video reproduced in the receiving device 3 is lowered, it becomes easy to transmit content data from the transmitting device 2 to the receiving device 3 without error. Therefore, even if the communication environment is bad, transmission will be successful. This function is realized by the encoding rate setting means 13 (see FIG. 2) of the transmission device 2 as described later.

 FIG. 2 shows the internal structure of the transmission device 2. As shown in FIG. 2, the transmission device 2 includes a first data holding unit 11, an encoding unit 12, an encoding rate setting unit 13, a second data holding unit 14, a receiving unit 15, a transmitting unit 16, a history recording unit 17 and Unreproduced part detection means 18 is provided. The transmission means 16 includes a switching means 19.

 [0039] The first data holding means 11 holds content data. The first data holding means 11 includes a recording medium and a device that reads information or data recorded on the recording medium. The recording medium of the first data holding unit 11 desirably has a large recording capacity. In addition, the recording medium of the data holding means 11 is desirably non-volatile and can store information or data for a long period of time. For example, the first data holding means 11 is a hard disk and a node disk drive. The first data holding means 11 includes a magnetic medium such as a tape and a reader thereof, an optical disc such as an LD (Laser Disc), a CD (Compact Disc), a DVD, a Blu-ray—Disk, and an HDDVD, and a reader thereof, or a card. Non-volatile memory such as type flash memory (memory card) and its reader may be used.

The encoding unit 12 encodes the content data held by the first data holding unit 11. As described above, the remote reproduction system 1 includes the transmission device 2 and the reception device 3. It has a function to set and change the encoding rate of content data according to the communication environment. The encoding means 12 encodes the content data in order to set the encoding rate according to the communication environment. The content data held by the first data holding means 11 is already encoded by an encoding method with a substantially high compression ratio such as MPEG2-TS (Moving Picture Experts Group phase 2-Transport Stream) or MPEG4 AVC (H. 264). Even when the encoding environment 12 needs to change the encoding rate of the content data according to the communication environment, the encoding means 12 first decodes the content data, and then the communication environment. Re-encode it at an encoding rate according to whether it is good or bad. The encoding unit 12 employs a configuration in which the encoding rate is changed while maintaining the encoding method (for example, MPEG2-TS) of the content data held by the first data holding unit 11. The encoding unit 12 may adopt a configuration in which the encoding rate is substantially changed by changing the encoding method of the content data held by the first data holding unit 11. For example, a configuration may be adopted in which the content data encoding scheme is changed to MPEG4 AVC for MPEG2-TS power. The encoding unit 12 has a function of changing the encoding rate or the encoding method, and the process of changing the encoding rate or the encoding method includes decoding. Therefore, the encoding means 12 is a complex data processing means having a decoding function in addition to a pure encoding function.

Furthermore, the encoder means 12 encodes the content data in two different periods. That is, considering the operation of the transmitting device 2 in operation, two types of periods can be defined according to the operation of the transmitting device 2. One of them is a period during which content data is transmitted to the receiving device 3 (hereinafter referred to as “transmission period”). The other is a period of waiting for transmission of content data to the receiving device 3 (hereinafter referred to as “transmission waiting period”). Specifically, during the transmission period, immediately after the content data transmission request transmitted from the receiving device 3 is received by the transmitting device 2, the transmission of content data to the receiving device 3 is started, and this transmission is interrupted. This is the period until stop or end. On the other hand, during the transmission standby period, the content held by the first data holding means 11 This is a part or all of the period from the time when data can be encoded to the time when the content data transmission request transmitted from the receiving device 3 is received by the transmitting device 2. More specifically, there are three typical examples of the transmission waiting period.

 (1) The period from immediately after the transmitter 2 is turned on until the content data transmission request is received;

 (2) A period from immediately after the content data transmission to the receiving device 3 is interrupted, stopped or terminated until the content data transmission request is received again;

 (3) When the content data to be transmitted is not held by the first data holding means 11, the content data to be sent is held by the first data holding means 11 (for example, the transmission device 2 is connected to the digital television broadcast). Connected to the network, received content data from a TV broadcasting station, and recorded it on the recording medium of the first data holding means 11; if the transmission device 2 has a reserved recording function, The period from the start of recording or the recording of a reserved program to the time when the content data transmission request is received.The encoding means 12 was first held by the first data holding means 11 during the transmission standby period. Encode the transmission start part of the content data. For example, the encoding unit 12 starts encoding the transmission start portion of the content data immediately after the transmission device 2 is turned on. Alternatively, the encoding means 12 starts encoding the content data transmission start part immediately after the transmission of the content data to the receiving device 3 is interrupted, stopped or terminated. Alternatively, the encoding unit 12 starts encoding the transmission start portion of the content data immediately after the content data to be transmitted is recorded on the recording medium of the first data holding unit 11. Next, the encoding means 12 encodes another part following the transmission start part in the content data held by the first data holding unit 11 during the transmission period.

The target to be encoded by the encoding means 12 during the transmission standby period is the transmission start portion of the content data. The transmission start portion is a part of the content data that is transmitted first by the transmission device 2 during the transmission period. Specifically, the transmission start part is the head part of the unreproduced part of the content data held by the first data holding means 11. When all of the content data has not been played back, the transmission start part is the top part of the content data. The size (range) of the transmission start portion of the content data can be determined in consideration of processing performance such as the encoding execution speed in the encoding means 12. For example, if the encoding unit 12 starts encoding the start position of the content data and completes it for 1 or 2 seconds, the transmission start part corresponds to a playback time of 1 or 2 seconds. Part of the content data.

 [0043] The encoding means 12 includes, for example, a combination of an encoder and a decoder, or a data processing unit (may be a transcoder) having these functions, and a control unit (for example, an arithmetic processing circuit and a semiconductor memory) that controls the timing of encoding. ) And can be realized.

[0044] The encoding rate setting means 13 sets the encoding rate of the encoding means 12 to be changeable. The encoding rate setting means 13 sets the encoding rate set immediately before the content data transmission to the receiving device 3 is interrupted, stopped or terminated as the encoding rate for encoding the transmission start portion of the content data. It is desirable. As a result, the encoding rate can be set according to the quality of the communication environment. That is, the quality of the communication environment between the transmission device 2 and the reception device 3 is mainly determined by the communication environment around the reception device 3. For example, if the user is in a large park with the receiving device 3, the communication environment between the transmitting device 2 and the receiving device 3 will be good. On the other hand, if the user has the receiving device 3 and is in a building, the communication environment between the transmitting device 2 and the receiving device 3 will be bad. When the user reproduces the content data by the receiving device 3 and then stops or terminates the content data, the user often reproduces the content data again at the same place. If so, the communication environment is often the same for the first playback and the second playback. Therefore, by setting the encoding rate that was set immediately before the transmission of content data to the receiving device 3 is interrupted, stopped, or ended as the encoding rate for encoding the transmission start portion of the content data, The encoding rate can be set according to the environment. The encoding rate set immediately before the transmission of the content data to the receiving device 3 is interrupted, stopped, or terminated is, for example, the encoding rate set in the encoding means 12. It is possible to know the drate by recording it on a recording medium and referring to this record. The encoding rate setting means 13 can be realized by an arithmetic processing unit and a semiconductor memory, for example.

 [0045] The second data holding means 14 holds the transmission start portion of the content data encoded by the encoder means 12. The second data holding means 14 includes a recording medium for holding the transmission start portion of the content data. As described above, the transmission start part is a part of content data of an amount corresponding to a playback time of 1 or 2 seconds, for example. Considering this, the recording medium of the second data holding means 14 is sufficient to be a recording medium having a small recording capacity (for example, several megano << it to several tens of megabytes). Further, the recording medium of the second data holding means 14 may be volatile or non-volatile. The recording medium of the second data holding means 14 is, for example, a semiconductor memory such as RAM or a hard disk. Further, since it is desirable to transmit the content data transmission start portion immediately after receiving the content data transmission request, it is desirable that the recording medium of the second data holding means 14 has a high reading speed. Considering this point, the recording medium of the second data holding means 14 is a semiconductor memory.

 The receiving unit 15 receives the content data transmission request transmitted from the receiving device 3.

 The receiving means 15 can be realized by a network control circuit or a communication interface, for example.

 The transmission unit 16 transmits the content data encoded by the encoding unit 12 to the reception device 3. When the receiving unit 15 receives a content data transmission request, the transmitting device 16 performs content data transmission processing in response to the request. The transmission means 16 has two transmission processes. First, the transmission means 16 transmits the transmission start portion of the content data held by the second data holding means 14. Next, the transmission means 16 transmits another part of the content data encoded by the encoding unit 12 following the transmission start part of the content data. The transmission means 16 can be realized by a network control circuit or a communication interface, for example. The transmission means 16 may be provided with a transmission buffer.

The transmission unit 16 includes a switching unit 19. The switching means 19 includes second data holding means 14 The transmission is switched from the transmission start portion of the content data held by the transmission to the transmission of another portion following the transmission start portion of the content data. The switching means 19 can be realized by a selector or a switching circuit, for example.

[0049] The history recording means 17 is information indicating the history of content data transmitted from the transmitting means 16 to the receiving apparatus 3 and played back by the receiving apparatus 3 (hereinafter referred to as "playback history information"). ). The reproduction history information can be created as follows, for example. First, when the reproduction of content data is interrupted, stopped, or ended, the receiving device 3 detects the interrupted position, stop position, or end position of the content data, and transmits information indicating this to the transmitting device 2. If the interruption of content data playback is an unexpected interruption of communication due to a bad communication environment, the receiving device 3 may send information indicating the interruption position of the content data immediately after the interruption. Have difficulty. In this case, information indicating the interruption position of the content data may be transmitted when communication is restored. Subsequently, the transmission apparatus 21 1S receives information indicating the interruption position, stop position, or end position of the content data, and records this information on a recording medium as reproduction history information. The history recording means 17 can be realized using a recording medium such as a hard disk or a semiconductor memory.

 [0050] The unreproduced part detection means 18 detects an unreproduced part of the content data held by the first data holding means 11 by referring to the reproduction history information. For example, the unreproduced part detection means 18 recognizes the interruption position or stop position of the content data by referring to the reproduction history information, and enters the content data, and the part following the interruption position or stop position is not recognized. Judged as the playback part. Further, when the end position of the content data is recognized by referring to the reproduction history information, the unreproduced part detecting means 18 determines that all the content data is an unreproduced part. When the reproduction history information is not recorded on the recording medium of the history recording unit 17, the unreproduced part detection unit 18 determines that all of the content data is an unreproduced part. The unreproduced part detecting means 18 can be realized by an arithmetic processing circuit and a semiconductor memory.

FIG. 3 shows an example of the operation of the transmission device 3. As shown in FIG. 3, when the user turns on the transmission device 3, first, the unreproduced part detection means 18 detects the unreproduced part of the content data held by the first data holding means 11 Unreproduced part detection process for (Step Sl). FIG. 4 shows an example of the unreproduced part detection process. As shown in FIG. 4, the unreproduced part detecting means 18 first checks the recording medium of the history recording means 17 and determines whether or not reproduction history information is recorded (step S21). When the reproduction history information is recorded (step S21: YES), the unreproduced part detection unit 18 reads the reproduction history information from the recording medium of the history recording unit 17. Subsequently, the unreproduced part detecting means 18 determines whether or not the reproduction history information is an information power indicating the end position of the content data (step S23). When the reproduction history information is not information indicating the end position of the content data (step S2 3: NO), the unreproduced part detection means 18 continues with the reproduction history information. It is determined whether the interruption position or the stop position indicated by the information is close to the end of the content data (step S24). When the interruption position or stop position is not close to the end of the content data (step S24), the unreproduced part detection means 18 determines that the part following the interruption position or stop position in the content data is an unreproduced part (step S25). ). On the other hand, when the playback history information is not recorded on the recording medium of the history recording means 17 (step S21: NO), or when the playback history information is information indicating the end position of the content data (step S23: YES) When the interruption position or stop position indicated by the history reproduction information is close to the end of the content data (step S24: YES), the unreproduced part detection means 18 determines that all of the content data is an unreproduced part (step S26).

Returning to FIG. 3, when the unreproduced part detection processing is completed, the encoding rate setting means 13 sets the encoding rate setting processing for setting the encoding rate of the encoding means 12 (step S2). FIG. 5 shows an example of the encoding rate setting process. As shown in FIG. 5, the encoding rate setting means 13 first determines whether or not a certain time (for example, approximately one hour) has elapsed since the transmission of content data was interrupted, stopped or terminated (step S31). ). When a certain time has elapsed since the transmission of content data was interrupted, stopped, or terminated (step S31: YES), the encoding rate setting means 13 sets a predetermined default encoding rate (step S32). ). On the other hand, when a certain time has not elapsed since the transmission of the content data was interrupted, stopped, or ended (step S31: NO), the encoding rate setting means 13 sends the content data. Set the encoding rate that was set immediately before the transmission was interrupted, stopped, or terminated (step S33).

 Returning to FIG. 3, when the encoding rate setting process is completed, the encoding means 12 is then held by the first data holding unit 11 and the beginning part of the unreproduced part of the content data is set as the transmission start part. This is encoded (step S3). Subsequently, the second data holding unit 14 holds the leading portion of the unreproduced portion of the encoded content data (step S4). Then, the transmission device 2 waits until the reception means 15 receives the content data transmission request transmitted from the reception device 3 (step S5: NO).

 [0054] When the reception means 15 receives the content data transmission request (step S5: YES), the transmission means 16 transmits the transmission start portion of the content data held by the second data holding means 14 to the reception device 3. (Step S6). That is, before the receiving means 15 receives the content data transmission request, the recording medium of the second data holding means 14 holds the transmission start portion of the content data encoded by the encoding means 12. ing. The transmission means 16 reads out the transmission start portion of the content data from the second data holding means 14 and immediately transmits it to the reception device 3.

[0055] After the receiving means 15 receives the content data transmission request, the encoding means 12 starts encoding the other part following the content data transmission start part almost simultaneously with the transmission of the content data transmission start part ( Step S7). That is, the encoding unit 12 reads the other part following the transmission start part of the content data from the first data holding unit 11 and starts to encode it. The other part of the encoded content data is supplied directly to the transmission means 16 without going through the second data holding means 14. When the transmission of the content data transmission start portion is completed (step S8: YES), the switching means 19 starts the transmission of the content data from the transmission of the content data transmission start part held by the second data holding means 14. Switch to the transmission of the other part following the transmission start part (step S9). The timing at which the transmission of the content data transmission start portion is completed and the timing at which the head portion of the other portion of the encoded content data is supplied to the transmission means 16 are set so as to match each other ( For example, the size of the transmission start part is set so that both timings coincide). Therefore, content data transmission The transmission of the transmission start part and the transmission of the other part of the content data are continuous. Even if the timings of the two are slightly deviated, by providing a buffer upstream or downstream of the transmission means 16, the timing deviation can be absorbed, and transmission continuity can be realized.

 [0056] Further, the transmission means 16 continues to transmit the other part of the content data (step S10). That is, the encoding unit 12 encodes the other parts of the content data held by the first data holding unit 11 one after another, and supplies this directly to the transmission unit 16 immediately. Then, the transmitting means 16 immediately transmits this to the receiving device 3.

 [0057] Subsequently, when transmission of the other part of the content data is interrupted, stopped, or terminated (step S11: YES), the process returns to step S1.

 FIG. 6 shows the encoding operation of the encoding unit 12 and the transmission operation of the transmission unit 16 side by side on the time axis. Hereinafter, the execution timing of the encoding operation and the transmission operation will be described with reference to FIG. For convenience of explanation, description of operations of the encoding rate setting means 13, the history recording means 17, and the unreproduced part detecting means 18 is omitted here.

[0059] Assume that the user turns on the transmitter 2 at time tO in FIG. Immediately after this, the encoding means 12 encodes the transmission start portion of the content data held by the first data holding means 11 (operation Al). Note that the transmission start portion at this point is, for example, the head portion of the content data. The transmission start portion of the encoded content data is held by the second data holding means 14. Next, it is assumed that the receiving means 15 receives the content data transmission request transmitted from the receiving device 3 at the time tl. Immediately after this, the transmission means 16 transmits the transmission start portion of the content data held by the second data holding means 14 to the reception device 3 (operation A2). At substantially the same time, the encoding means 12 encodes another part following the transmission start part of the content data held by the first data holding means 11 (operation A3). Next, it is assumed that transmission of the transmission start portion of the content data held by the second data holding means 14 is completed at time t2. At substantially the same time, the encoding of the other part of the content data is finished and the other part of the encoded content data is directly supplied to the transmission means 16 without going through the second data holding means 14. At this time, the switching means 19 includes the second data holding means 1 Switching from the transmission start part of the content data held in step 4 to the transmission of another part following the transmission start part of the content data. As a result, when the transmission of the content data transmission start portion is completed, the transmission of the other portion of the content data is performed continuously (operation A4). Next, at time t3, transmission of the other part of the content data is stopped. Immediately after this, the encoding unit 12 encodes the transmission start portion of the content data held by the first data holding unit 11 (operation A5). Note that the transmission start portion at this point is the head portion of the unreproduced portion of the content data following the content data reproduction stop position. The transmission start part of the encoded content data is held by the second data holding means 14. At this time, the switching unit 19 switches the path so as to connect the second data holding unit 14 and the transmission unit 16. Next, it is assumed that the receiving means 15 receives the content data transmission request transmitted from the receiving device 3 again at time t4. Immediately after this, the transmission means 16 transmits the transmission start portion of the content data held by the second data holding means 14 to the receiving device 3 (operation A6). At substantially the same time, the encoding means 12 encodes the other part following the transmission start part of the content data held by the first data holding means 11 (operation A7). Next, it is assumed that the transmission of the transmission start portion of the content data held by the second data holding means 14 is completed at time t5. At substantially the same time, the encoding of the other part of the content data is completed, and the other part of the encoded content data is directly supplied to the transmission means 16 without going through the second data holding means 14. At this time, the switching unit 19 switches from transmission of the content data transmission start part held by the second data holding unit 14 to transmission of another part following the transmission start part of the content data. As a result, when the transmission of the transmission start portion of the content data is completed, the transmission of the other portion of the content data is continuously performed subsequently (operation A8).

The important point in Fig. 6 is that the encoding operation A1 is performed during the transmission waiting period corresponding to the period from time tO to time tl. That is, the encoding operation A1 is performed before the content data transmission request from the receiving device 3 is received. Another important point in Fig. 6 is that the encoding operation A5 is performed during the transmission waiting period corresponding to the period from time t3 to time t4. That is, the encoding operation A5 is This is executed until the content data transmission is stopped and the content data transmission request is received again.

 As described above, the transmission device 2 encodes the content data transmission start portion during the transmission standby period before the content data transmission request is received, and the second data holding unit 14 encodes this. Hold. Then, when the content data transmission request is received, the transmission device 2 first transmits the transmission start portion of the content data that has already been encoded and is held by the second data holding means 14. As a result, it is possible to shorten the time until the transmission of the content data is started after the transmission device 2 force S content data transmission request is received. Because the encoding of the content data transmission start portion has already been completed before the content data transmission request is received, the content data transmission request that does not spend the encoding execution time of the content data transmission start portion can be immediately responded to. This is because the transmission start portion of the content data can be transmitted. As a result, it is possible to shorten the time from when the user performs an operation for starting the reproduction of the content data until the actual reproduction of the content data is started. Therefore, it is possible to realize a remote reproduction system that does not cause the user to feel troublesome operation, has excellent response, and has excellent operability. For example, if it takes several seconds from when the user presses the playback start button of the receiving device 3 until the playback video of the content data is actually displayed on the display, the user has nothing to do with pressing the playback start button. You will feel unresponsive and feel anxious. However, according to the video playback system 1 according to the embodiment of the present invention, the delay time from when the user presses the playback start button of the receiving device 3 until the playback video of the content data is actually displayed on the display is shortened. Therefore, the user's anxiety can be solved.

 [0062] (Second embodiment of remote reproduction system)

 In the second embodiment of the remote reproduction system of the present invention, the transmitting device encrypts the content data and then transmits it to the receiving device. The receiving device reproduces the received content data by streaming while decoding the received content data.

FIG. 7 shows the internal structure of the transmission apparatus in the second embodiment of the remote reproduction system. As shown in FIG. 7, the transmission device 20 uses an encryption means 21 instead of the encoding means 12. Except for the points provided, it is the same as the transmitter 1 shown in FIG.

 The encryption key means 21 encrypts the content data held by the first data holding means 11. The encryption means 21 performs content data encryption in two different periods. That is, like the encoding unit 12, the encryption unit 21 first encrypts the transmission start portion of the content data held by the first data holding unit 11 during the transmission standby period. Next, the encryption means 21 encrypts the other part following the transmission start part in the content data held by the first data holding unit 11 during the transmission period.

 [0065] The encryption key means 21 performs encryption during the transmission standby period is the content data transmission start portion. The transmission start part is the head part of the unreproduced part of the content data held by the first data holding means 11. When all of the content data has not been played back, the transmission start part is the top part of the content data. The size (range) of the transmission start portion of the content data can be determined in consideration of processing performance such as the encryption execution speed in the encryption means 21.

 [0066] The encryption means 21 can be realized by, for example, an encryptor and a control unit that controls the timing of encryption.

 [0067] The second data holding means 14 holds the transmission start portion of the encrypted content data before the content data transmission request is received. When the content data transmission request is received, the transmission means 16 uses the second data as the second data holding start portion of the content data held in the recording medium of the second data holding means 14 after the encryption has already been completed. The recording medium force of the holding means 14 is read out and immediately transmitted to the receiving device.

[0068] As described above, according to the transmission device 20, it is possible to shorten the time from when the content data transmission request is received until the transmission of the content data is started. This is because the encryption for the transmission start portion of the content data has already been completed before the content data transmission request is received, so the content that does not spend the encryption execution time of the transmission start portion of the content data. This is because the transmission start part of the content data can be transmitted in response to the data transmission request. As a result, it is possible to shorten the time until the user actually starts the reproduction of the content data by performing the operation of starting the reproduction of the content data. Therefore, the user feels troublesome. This makes it possible to realize a remote playback system that does not cause blurring and has excellent response and operability.

 [0069] (Third embodiment of remote reproduction system)

 In the third embodiment of the remote reproduction system of the present invention, the transmitting apparatus holds content data encrypted in advance. The transmitting device decrypts the content data and transmits it to the receiving device. The receiving device reproduces the received content data by streaming.

 FIG. 8 shows the internal structure of the transmitting apparatus in the third embodiment of the remote reproduction system. As shown in FIG. 8, the transmitting device 30 includes a decrypting unit 31 instead of the encoding unit 12, and the content data stored in the first data holding unit 11 is encrypted in advance. Except for this point, it is the same as the transmitter 1 shown in FIG.

 The decryption means 31 decrypts the encrypted content data held by the first data holding means 11. The decryption means 31 performs content data decryption in two different periods. That is, like the encoding unit 12, the decrypting unit 31 first decrypts the transmission start portion of the encrypted content data held by the first data holding unit 11 during the transmission waiting period. Next, the decrypting means 31 decrypts the encrypted content data held by the first data holding unit 11 during the transmission period and the other part following the transmission start part.

 [0072] The target to be decrypted by the decrypting means 31 during the transmission standby period is the content data transmission start portion. The transmission start part is the head part of the unreproduced part of the content data held by the first data holding means 11. When all of the content data has not been played back, the transmission start part is the top part of the content data. The size (range) of the transmission start portion of the content data can be determined in consideration of processing performance such as the decryption key execution speed in the decryption key means 31.

 [0073] The decoding means 31 can be realized by, for example, a decryptor, a control unit for controlling the timing of decoding, and the like.

[0074] The second data holding means 14 holds the transmission start portion of the decrypted content data before the content data transmission request is received. The transmission means 16 is content When the data transmission request is received, the transmission start portion of the content data held in the recording medium of the second data holding means 14 that has already been decrypted at this time is designated as the recording medium of the second data holding means 14. Read out and send it immediately to the receiving device.

[0075] As described above, according to the transmission device 30, it is possible to shorten the time from when the content data transmission request is received until the transmission of the content data is started. This is because the content data transmission start part has already been decrypted before the content data transmission request is received, so that the content without spending the decryption execution time of the content data transmission start part. This is because the transmission start part of the content data can be transmitted in response to the data transmission request. As a result, it is possible to shorten the time until the user actually starts the reproduction of the content data by performing the operation of starting the reproduction of the content data. Therefore, it is possible to realize a remote reproduction system that does not cause the user to feel troublesome operation, has excellent response, and has excellent operability.

 [0076] (Fourth embodiment of remote reproduction system)

 In the fourth embodiment of the remote reproduction system of the present invention, the transmission device holds content data compressed in advance. The transmitting device decompresses the content data and transmits it to the receiving device. The receiving device reproduces the received content data by streaming.

 FIG. 9 shows the internal structure of the transmission device in the fourth embodiment of the remote reproduction system. As shown in FIG. 9, the transmitting device 40 includes decompression means 41 instead of the encoding means 12, and the content data held in the first data holding means 11 are pre-compressed. Except for this point, it is the same as the transmitter 1 shown in FIG.

The decompressing unit 41 decompresses the compressed content data held by the first data holding unit 11. The decompression means 41 decompresses content data during two different periods. That is, like the encoding unit 12, the decompressing unit 41 first decompresses the transmission start portion of the compressed content data held by the first data holding unit 11 during the transmission standby period. Next, the decompression means 41 transmits another part of the compressed content data held by the first data holding unit 11 following the transmission start part during the transmission period. Stretch.

 [0079] The target to which the decompression means 41 decompresses during the transmission standby period is the content data transmission start portion. The transmission start part is the head part of the unreproduced part of the content data held by the first data holding means 11. When all of the content data has not been reproduced, the transmission start part is the head part of the content data. The size (range) of the content data transmission start portion can be determined in consideration of processing performance such as the decompression execution speed in the decompression means 41.

 The expansion means 41 can be realized by, for example, a unit including a semiconductor memory in which an arithmetic processing circuit and an expansion control program are stored, and a control unit that controls the timing of expansion.

 [0081] The second data holding unit 14 holds the transmission start portion of the extended content data before the content data transmission request is received. When the content data transmission request is received, the transmission means 16 uses the second data holding means as the second data holding means to transmit the content data transmission start portion already decompressed at this point and held in the recording medium of the second data holding means 14. The 14 recording medium power is also read out and immediately transmitted to the receiving device.

 [0082] As described above, according to the transmission device 40, it is possible to shorten the time from when the content data transmission request is received until the transmission of the content data is started. This is because before the content data transmission request is received, the content data transmission start part has already been decompressed, so content data transmission without spending the decompression execution time of the content data transmission start part. This is because the transmission start part of the content data can be transmitted in response to the request. As a result, it is possible to shorten the time from when the user performs an operation for starting the reproduction of the content data until the actual reproduction of the content data is started. Therefore, it is possible to realize a remote reproduction system that does not make the user feel inconvenienced, has excellent response, and has excellent operability.

It should be noted that the first to fourth embodiments as described above can also be realized as a computer program. For example, the first data holding unit 11, the encoding unit 12, the encoding rate setting unit 13, the second data holding unit 14, the receiving unit 15, and the transmitting unit 1 shown in FIG. 6.History recording means 17 and unreproduced part detection means 18 etc. are realized by using standardly provided node software such as CPU, main memory, input / output device, communication interface and node disk. Create a computer program and load it into your computer. As a result, the computer can function as the transmitter 2.

 [0084] Further, the first and fourth embodiments of the remote reproduction system described above are also embodiments of the content data transmission method of the present invention. For example, step S3 in FIG. 3 is a specific example of the first encoder, step S4 is a specific example of the data holding process, and step S6 is a specific example of the first transmission process. Step S7 is a specific example of the second encoding process, step S10 is a specific example of the second transmission process, and step S9 is a specific example of the switching process.

 Example

 Hereinafter, embodiments of the remote reproduction system of the present invention will be described with reference to the drawings. In the following embodiment of the remote reproduction system, the transmission apparatus holds the content data encrypted in advance. The transmitting device decodes the content data, and subsequently decodes the decrypted content data. Further, the transmitting device encodes the decoded content data at an encoding rate according to the quality of the communication environment. The encoded content data is encrypted, and the encrypted content data is transmitted to the receiving device. The receiving device decrypts the received content data and plays it by streaming. Before receiving the content data transmission request transmitted from the receiving device, the transmitting device performs decoding, decoding, encoding and encryption of the transmission start portion of the content data, and these processes are performed. The transmission start part of the received content data is held in the transmission start part holding RAM. When the content data transmission request is received, the transmission device first transmits the transmission start portion of the content data held in the transmission start portion holding RAM.

[0086] Now, an embodiment of the remote reproduction system of the present invention will be described more specifically with reference to FIG. As shown in FIG. 10, the remote reproduction system 100 includes a transmission device 60 and a reception device 90. The transmission device 60 and the reception device 90 are connected to a computer network 8. They are connected to each other via 0. Encrypted content data is recorded on the hard disk built in the hard disk drive 61 of the transmission device 60. Immediately after the user turns on the transmission device 60, the data processing control unit 71 decrypts, decodes, encodes and encrypts the encrypted content data transmission start part recorded on the hard disk. Give instructions to perform traps. In response to this, the decryptor 62 decrypts the transmission start portion of the encrypted content data recorded in the hard disk drive 61. Subsequently, the decoder 63 decodes the transmission start portion of the decrypted content data. Subsequently, the encoder 64 encodes the transmission start portion of the decoded content data at an encoding rate according to whether the communication environment is good or bad. Subsequently, the encryptor 65 encrypts the transmission start portion of the encoded content data. The transmission start portion of the content data that has been decrypted, decoded, encoded, and encrypted is stored in the transmission start portion holding RAM 66.

 When the user presses a reproduction start button (not shown) provided on operation unit 95 of receiving device 90, content data transmission request unit 96 outputs a content data transmission request. The content data transmission request is transmitted to the transmission device 60 via the network control unit 94 and the computer network 80 of the reception device 90. The network control unit 73 of the transmission device 60 receives the content data transmission request. In response to this, the transmission control unit 72 connects the transmission start part holding RAM 66 and the transmission buffer 68 via the selector 67, and transmits the transmission start part of the content data stored in the transmission start part holding RAM 66. Supply to buffer 68. The transmission start portion of the content data supplied to the transmission buffer 68 is immediately transmitted to the receiving device 90 via the network control unit 73 and the computer network 80. The receiving device 90 receives the content data transmission start portion, stores it in the receiving buffer 91, immediately decodes it by the decryptor 92, and subsequently decodes it by the decoder 93, and outputs it to an output device such as a display (not shown). Output to.

[0088] On the other hand, immediately after the content data transmission request is received, the transmitting device 60 decodes, decodes, and encodes the other parts following the content data transmission start part almost simultaneously with the transmission of the content data transmission start part. And encryption is performed. That is, under the control of the data processing unit 71, the decryptor 62, the decoder 63, the encoder 64 and the encoder The encryptor 65 decrypts, decodes, encodes, and encrypts the other part of the content data recorded on the hard disk. The other part of the content data subjected to these processes is directly output to the selector 67 side through the transmission start part holding RAM 66. Thus, when the other part of the content data is output toward the selector 67, the transmission of the transmission start part of the content data stored in the transmission start part holding RAM 66 is completed. At this moment, the transmission control unit 72 switches the selector 67 and directly connects the encryptor 65 and the transmission buffer 68. As a result, the other part of the content data output from the encoder 65 continues to the transmission start part of the content data, and continues to the receiving device 90 via the transmission buffer 68, the network control unit 73, and the computer network 80. Sent to. The receiving device 90 receives the other part of the content data, stores it in the receiving buffer 91, immediately decodes it by the decryptor 92, subsequently decodes it by the decoder 93, and outputs it to an output device such as a display. In receiving device 90, the other part of the content data is reproduced continuously with the transmission start part of the previously received content data. That is, the content data transmission start portion and the other portions are continuous at the latest at the output stage of the transmission buffer 68, and become a series of content data when received by the receiving device 90. ing.

 On the other hand, when the user presses a playback stop button (not shown) of the operation unit 95 of the receiving device 90, the history generation unit 97 of the receiving device 90 causes the content data playback history information (for example, content) Information indicating the data stop position). The reproduction history information is transmitted to the transmission device 60 via the network control unit 94 and the computer network 80. The transmission device 60 receives the reproduction history information and records it in the history recording unit 69 on the hard disk.

[0090] After the transmission of the content data is stopped by the user's playback stop instruction, the unplayed part detection unit 70 of the transmission device 60 refers to the playback history information recorded in the history recording unit 69, and Recognize the position where playback stopped. Then, the non-reproduced part detection unit 70 determines that the position power next to the position where the reproduction of the content data has stopped is the unreproduced part. Subsequently, the data processing control unit 71 Sends an instruction to decrypt, decode, encode, and encrypt the beginning of the unreproduced portion of the recorded encrypted content data (this portion is the transmission start portion at this point) . In response to this, the decryptor 62, the decoder 63, the encoder 64, and the decryptor 65 decrypt, decode, encode, and encrypt the head portion of the unreproduced portion of the content data. The leading portion of the unreproduced portion of the content data that has been decrypted, decoded, encoded, and encrypted is stored in the transmission start portion holding RAM 66.

 [0091] When the user presses the playback start button provided on the operation unit 95 of the receiving device 90 again, and thereby the content data transmission request is received by the transmitting device 60, the transmission control unit 72 responds accordingly. The transmission start part holding RAM 66 and the transmission buffer 68 are connected via the selector 67, and the start part of the unreproduced part of the content data stored in the transmission start part holding RAM 66 is sent to the transmission buffer 68 and the network control unit. The data is transmitted to the receiving device 90 via 73 and the computer network 80. At almost the same time, the transmitting device 60 decrypts, decodes, encodes, and encrypts the other part following the beginning of the unreproduced part of the content data. The selector 67 is switched so as to connect directly, and the other part of the unreproduced part of the content data is transmitted to the receiving device 90. The receiving device 90 sequentially receives the beginning portion of the unreproduced portion of the content data and the other portions following the sequential portion, and immediately decodes and decodes this while storing it in the receiving buffer 91, and outputs it such as a display. Output to.

As described above, according to the remote reproduction system 100, it is possible to shorten the time from when the transmission device 60 receives the content data transmission request until transmission of the strong content data is started. This is because the content data transmission start part has already been decrypted, decoded, encoded, and encrypted before the content data transmission request is received. This is because the transmission start portion of the content data can be transmitted immediately in response to the content data transmission request without spending the execution time of encoding and encryption. As a result, it is possible to shorten the time from when the user performs an operation of starting the reproduction of the content data to actually start the reproduction of the content data. Therefore, to the user This makes it possible to realize a remote playback system that does not feel annoying operation, has excellent response, and has excellent operability.

 Note that the present invention can be changed as appropriate without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a remote reproduction system and a transmission device that involve such a change. The content data transmission method and the computer program are also included in the technical idea of the present invention.

 Industrial applicability

[0094] The content data transmission device, content data transmission method, and remote reproduction system according to the present invention are, for example, an AV (Audio Visual) device and a network having a function of performing information communication by connecting to a communication network such as the Internet. It can be used for home appliances, and connected to mobile communication networks such as mobile phone networks, IMT-2000 (International Mobile Telecommunication 2000), PHS (Personal Handyphone System), and wireless LAN (Wireless Local Area Network). Therefore, it can be used for mobile terminals equipped with a function for information communication. In addition, it can be used for a content data transmission device or the like that is mounted on or can be connected to various computer devices for consumer use or business use, for example.

Claims

The scope of the claims
 [1] A transmitting device that transmits the content data to the receiving device in response to a content data transmission request transmitted by the receiving device in order to reproduce the content data by streaming in the receiving device,
 First data holding means for holding content data;
 The time when the content data held by the first data holding means can be encoded The first data holding means during the transmission waiting period included in the period until the content data transmission request is received Encoding means for encoding the transmission start part of the content data held by
 Second data holding means for holding a transmission start portion of the content data encoded by the encoder means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A transmitting device comprising: a transmitting means for transmitting the part to the receiving device!
[2] The transmission means includes switching means for switching from transmission of the transmission start part of the content data held by the second data holding means to transmission of another part following the transmission start part of the content data. The transmitter according to claim 1, wherein the transmitter is characterized in that:
 [3] The transmission device according to claim 1, wherein the encoding unit encodes the head portion of the content data held by the first data holding unit as the transmission start portion.
[4] History recording means for recording reproduction history information indicating a history of content data transmitted from the transmitting means to the receiving apparatus and reproduced by the receiving apparatus; and reproduction history information recorded by the history recording means. An unreproduced part detecting means for detecting an unreproduced part of the content data held by the first data holding means by referring to
The encoding means is the content detected by the unreproduced part detecting means. 2. The transmission apparatus according to claim 1, wherein a leading portion of an unreproduced portion of data is encoded as the transmission start portion.
[5] The transmission device according to claim 1, wherein the encoding means starts encoding the transmission start portion of the content data immediately after the transmission device is turned on.
 6. The encoding unit according to claim 1, wherein the encoding unit starts encoding the transmission start portion of the content data immediately after the transmission of the content data to the receiving device is interrupted, stopped, or ended. The transmitting device according to 1.
 [7] It further comprises an encoding rate setting means for setting the encoding rate of the encoding means to be changeable,
 The encoding rate setting means sets the encoding rate that was set immediately before the content data transmission to the receiving device was interrupted, stopped, or ended as an encoding rate for encoding the content data transmission start portion. The transmitter according to claim 1, characterized in that:
[8] A transmission device and a reception device connected to each other via a network, and the transmission device transmits content data to the reception device in response to the transmitted content data transmission request. A remote reproduction system in which the receiving device reproduces the content data by streaming;
 The transmitter is
 First data holding means for holding content data;
 The time when the content data held by the first data holding means can be encoded The first data holding means during the transmission waiting period included in the period until the content data transmission request is received Encoding means for encoding the transmission start part of the content data held by
 Second data holding means for holding a transmission start portion of the content data encoded by the encoder means;
Receiving means for receiving a content data transmission request transmitted from the receiving device; and when the content data transmission request is received by the receiving means, A remote reproduction system comprising: a transmission unit configured to transmit a transmission start portion of the content data held by the data holding unit to the reception device.
 [9] In the content data transmission method in the transmission device, the content data is transmitted to the reception device in response to the content data transmission request transmitted by the reception device in order to reproduce the content data by streaming in the reception device Therefore, it is possible to encode the content data held in the first data holding unit. During the transmission waiting period included in the period until the content data transmission request is received, A first encoding step for encoding the transmission start portion of the content data held in the data holding unit;
 A data holding step of holding a transmission start part of the content data encoded in the first encoding step in a second data holding unit;
 A first transmission step of transmitting, to the receiving device, a transmission start portion of the content data held in the second data holding unit when the content data transmission request is received. Data transmission method.
[10] After the content data transmission request is received, a second encoding step of encoding the other part following the transmission start part in the content data held in the first data holding unit;
 And a second transmission step of transmitting the other part of the content data encoded in the second encoding step to the receiving device following the transmission start portion of the content data. The content data transmission method described in Item 9.
 [11] The range of claim 10, wherein the second transmission step includes a switching step of switching to transmission power of a transmission start portion of the content data to transmission of another portion of the content data. The content data transmission method described.
[12] A transmitting device that transmits the content data to the receiving device in response to the content data transmission request transmitted by the receiving device in order to reproduce the content data by streaming in the receiving device,
First data holding means for holding content data; The time when the content data held by the first data holding means can be encrypted. The transmission wait period included in the period until the content data transmission request is received. An encryption means for encrypting the transmission start part of the content data held by the data holding means;
 Second data holding means for holding a transmission start portion of the content data encrypted by the encryption key means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A transmitting device comprising: a transmitting means for transmitting the part to the receiving device!
[13] A transmitter and a receiver connected to each other via a network are provided, and the transmitter transmits content data to the receiver in response to the content data transmission request transmitted by the receiver. A remote reproduction system in which the receiving device reproduces the content data by streaming;
 The transmitter is
 First data holding means for holding content data;
 The time when the content data held by the first data holding means can be encrypted. The transmission wait period included in the period until the content data transmission request is received. An encryption means for encrypting the transmission start part of the content data held by the data holding means;
 Second data holding means for holding a transmission start portion of the content data encrypted by the encryption key means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A remote reproduction system comprising: a transmission means for transmitting the portion to the receiving device.
[14] In order to reproduce the content data by streaming in the receiving device, the content data is transmitted in advance according to the content data transmission request transmitted by the receiving device. A content data transmission method in a transmitting device for transmitting to a receiving device, wherein the content data held in the first data holding unit can be encrypted. When the content data transmission request is received An encryption step of encrypting a transmission start part of the content data held in the first data holding unit during a transmission waiting period included in the period up to
 A data holding step for holding a transmission start portion of the content data encrypted in the encryption step in a second data holding unit;
 A transmission step of transmitting the content data transmission start part held in the second data holding unit to the receiving device when the content data transmission request is received! / Content data transmission method.
[15] A transmitting device that transmits the content data to the receiving device in response to a content data transmission request transmitted by the receiving device in order to reproduce the content data by streaming in the receiving device,
 First data holding means for holding encrypted content data;
 Power that enables decryption of the encrypted content data held by the first data holding means During a transmission waiting period included in a period until the content data transmission request is received Decrypting means for decrypting the transmission start portion of the encrypted content data held by the first data holding means;
 Second data holding means for holding a transmission start portion of the content data decrypted by the decryption key means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A transmitting device comprising: a transmitting means for transmitting the part to the receiving device!
[16] A transmission device and a reception device connected to each other via a network, and the transmission device transmits content data to the reception device in response to the content data transmission request transmitted. A remote reproduction system in which the receiving device reproduces the content data by streaming; The transmitter is
 First data holding means for holding encrypted content data;
 Power that enables decryption of the encrypted content data held by the first data holding means During a transmission waiting period included in a period until the content data transmission request is received Decrypting means for decrypting the transmission start portion of the encrypted content data held by the first data holding means;
 Second data holding means for holding a transmission start portion of the content data decrypted by the decryption key means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A remote reproduction system comprising: a transmission means for transmitting the portion to the receiving device.
[17] In the content data transmission method in the transmission device, the content data is transmitted to the reception device according to the content data transmission request transmitted by the reception device in order to reproduce the content data by streaming in the reception device. A power level that enables decryption of the encrypted content data held in the first data holding unit during a transmission waiting period included in a period until the content data transmission request is received A decryption step of decrypting a transmission start portion of the encrypted content data held in the first data holding unit;
 A data holding step of holding a transmission start part of the content data decrypted in the decryption step in a second data holding unit;
 A transmission step of transmitting the content data transmission start part held in the second data holding unit to the receiving device when the content data transmission request is received! / Content data transmission method.
[18] A transmitting device that transmits the content data to the receiving device in response to the content data transmission request transmitted by the receiving device in order to reproduce the content data by streaming in the receiving device,
First data holding means for holding compressed content data; The time when the compressed content data held by the first data holding means can be decompressed. During the transmission waiting period included in the period until the content data transmission request is received, Decompression means for decompressing the transmission start portion of the compressed content data held by the data holding means;
 Second data holding means for holding a transmission start portion of the content data expanded by the expansion means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A transmitting device comprising: a transmitting means for transmitting the part to the receiving device!
[19] A transmission device and a reception device connected to each other via a network, wherein the transmission device transmits content data to the reception device in response to the content data transmission request transmitted. A remote reproduction system in which the receiving device reproduces the content data by streaming;
 The transmitter is
 First data holding means for holding compressed content data;
 The time when the compressed content data held by the first data holding means can be decompressed. During the transmission waiting period included in the period until the content data transmission request is received, Decompression means for decompressing the transmission start portion of the compressed content data held by the data holding means;
 Second data holding means for holding a transmission start portion of the content data expanded by the expansion means;
 Receiving means for receiving a content data transmission request transmitted from the receiving device; and starting transmission of content data held by the second data holding means when the content data transmission request is received by the receiving means A remote reproduction system comprising: a transmission means for transmitting the portion to the receiving device.
[20] In order to reproduce the content data by streaming in the receiving device, the content data is sent in advance according to the content data transmission request transmitted by the receiving device. A content data transmitting method in a transmitting device for transmitting to a receiving device, which is capable of decompressing compressed content data held in a first data holding unit, wherein the content data transmission request is received A decompression step of decompressing a transmission start portion of the compressed content data held in the first data holding unit during a transmission standby period included in the period until the time;
 A data holding step for holding a transmission start portion of the content data expanded in the expansion step in a second data holding unit;
 A transmission step of transmitting the content data transmission start part held in the second data holding unit to the receiving device when the content data transmission request is received! / Content data transmission method.
[21] A computer program for causing a computer to function as the transmission device according to claim 1.
[22] A computer program for causing a computer to function as the transmission device according to claim 12.
[23] A computer program for causing a computer to function as the transmission device according to claim 15.
[24] A computer program for causing a computer to function as the transmission device according to claim 18.
PCT/JP2006/304782 2005-03-11 2006-03-10 Content data transmission device, content data transmission method, and remote reproduction system WO2006095868A1 (en)

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