JP2000165844A - System and method for reproducing continuous media streams - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and simple system capable of reducing degradation in the quality of continuous media streams to be reproduced even when the load of a transmission line gets light or heavy by successively reading and reproducing the contents of continuous media streams stored in a buffer part through a reproducing part. SOLUTION: The contents of continuous media streams received through an I/F part 110 are stored in a buffer part 130. A reproducing part 150 successively reads and reproduces the contents of continuous media streams stored in the buffer part 130. Then, non-reproduced contents stored on a disk part 140 are read out, written in an 'empty buffer' and reproduced. Thus, the reproduction of streams can be immediately restarted and in spite of whether the load of internet is light or heavy, the degradation in the quality of reproduced media streams caused by instability on the transmission line of internet can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system and a method for reproducing a continuous media stream transmitted from a transmitting device while receiving the media stream by a receiving and reproducing device.
World Wide Web (W)
The present invention relates to a system and a method for playing back a continuous media stream transmitted via WW).

[0002]

2. Description of the Related Art In recent years, services for providing audio and / or video have been provided via the WWW. Broadly speaking, data transmission methods include a download method and a stream method. The download method downloads all media such as audio or video before playing them. This method has the advantage that even if the load on the transmission path is heavy, it does not affect the quality of playback, but on the other hand, the disadvantage is that it takes time to download, and it is necessary to download all when you want to hear some information And that playback in real time is not possible. The stream method sequentially reproduces a continuous stream while transmitting it. This method has the advantage that it can be reproduced immediately upon request and can be reproduced in real time. On the other hand, the disadvantage of the stream method is that a wide bandwidth is required for the transmission path, and the load on the transmission path is light. Are likely to affect reproduction quality, and a server for flow control is required.

[0003] A large number of systems employing the stream system in the prior art are provided on the market. These products use continuous media stream transmission technology to transmit continuous media, such as audio and video, over the Internet. As shown in FIG. 1, a user can reproduce audio and video contents transmitted via the Internet by using the reception / reproduction device (10) of the system. These prior arts use two buffers (16). One is a reception buffer, and the other is a reproduction buffer. When the reception buffer becomes full (Full, full, hereinafter full) and all the data in the reproduction buffer has been reproduced, these two buffers are switched. Thus, a continuous audio / video stream can be continuously reproduced.

[0004]

However, these prior arts still require a wide bandwidth on the transmission line, and the lightness of the load on the transmission line tends to affect the quality of the continuous media stream to be reproduced. The problem remains.
In the Internet, when access from a user to a server is concentrated at one time, a load on a transmission path increases, and reduction of a transmission bandwidth is inevitable. Therefore, the conventional technology cannot flexibly cope with the instability of the Internet. It is a major problem that continuous media streams such as music are not played back continuously. An object of the present invention is to provide an inexpensive and simple system for reducing the deterioration of the quality of a continuous media stream to be reproduced even if the load on a transmission line occurs, and a method for realizing the system.

[0005]

In order to achieve the above object, the present invention proposes a buffering and caching method for a continuous media stream as shown in FIGS. In other words, continuous media such as audio and video are transmitted in the form of a stream over the Internet, and the receiving and reproducing device uses a circular buffer composed of a plurality of buffers to adjust the transmission speed and the reproducing speed while synchronizing the media. Play back continuously. In the implementation, first, all buffers are cleared to be "empty buffers". One of them is received as a “reception buffer”. When this "reception buffer" becomes full, the data in it is stored on the disk and played back simultaneously. In addition, using the next free buffer,
Continue receiving the stream. When the storage and reproduction of the buffer data shown in FIG. 4 on the caching disk is completed, the buffer is cleared to be an "empty buffer"
Use it again as a "receive buffer".

In the prior art, as shown in FIG. 1, a "reception buffer" and a "reproduction buffer" are fixed at the same size. In the circular buffer method of the present invention, the size of the buffer actually used for reception (the sum of the “reception buffer” and all “empty buffers”) and the size of the buffer used for reproduction (“reproduction buffer” and all “full buffers”) The sum of the "buffers" is not always the same, and changes dynamically according to the reception / reproduction status of the system. For example, if the reception speed becomes faster than the reproduction speed, the number of “full buffers” storing unreproduced contents increases, and the size of the buffer that can be used for reproduction increases. As the playback speed becomes faster than the reception speed, the number of “empty buffers” increases. In general, it is difficult to guarantee the communication bandwidth of the Internet for a certain period of time, so that the reception speed becomes faster than the reproduction speed, or conversely, becomes slower. The circulating buffer of the present invention can flexibly cope with such a situation, and can solve various problems caused by the instability of the bandwidth of the transmission line of the Internet.

[0007] Further, the reproduction may be temporarily stopped by the operation of the user. At this time, all buffers may be full. In the conventional method, reception is stopped and it is necessary to wait until reproduction is resumed. According to the method of the present invention, the full "reception buffer" can be cached on the disk, and the "reception buffer" can be opened and used again for reception. Thus, even if the reproduction is paused, the reception can be performed continuously without pausing. When the reproduction is resumed, the content stored on the disc is read out, and the content is written to the “empty buffer” and reproduced, whereby the reproduction of the stream can be immediately resumed. As a result, the transfer capacity of the Internet can be used to the maximum, regardless of the load of the Internet. According to the present invention, the receiving unit receives the content to be reproduced later and stores it on a disc as long as the capacity of the transmission path permits, regardless of the reproduction speed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 2 is a block diagram showing an outline of the present invention. The main components of the present invention will be described. The main components include a transmitting device (200), a data transmission path (180), and a receiving and reproducing device (100). The transmission device (200) includes a transmission unit (222), a transmission data storage unit (232), an I / F unit (212), and the like. Components unnecessary for the description of the present invention are omitted. Transmission unit (2
22) transmits the continuous media stream read from the transmission data storage section (232) via the I / F section (212) in response to a request from the reception / reproduction device (100). At this time, the transmission unit (222) divides the data into transmission units according to a predetermined rule and transmits the data. The data transmission path (180) is, for example, a communication line for transferring data, but is WWW in this embodiment.

The reception / reproduction device (100) has an I / F unit (1
10), receiving unit (120), buffer unit (130), caching disk unit (140), reproducing unit (15)
0), controller unit (170), user input unit (16)
0) and the like. The continuous media stream (400) shown in FIG. 5 is transmitted from the transmitting device (200). The contents of the continuous media stream (400) received via the I / F unit (110) are stored in the buffer unit (1).
30). At this time, the continuous media stream (400) is stored for each transmission unit. Reproduction unit (1
50) sequentially reads and reproduces the contents of the continuous media stream stored in the buffer unit (130). These unplayed contents are stored in the caching disk unit (140). caching·
When the unplayed content stored in the disk unit (140) comes to be played back, the buffer unit (13
Return to 0) and wait for playback. Receiving and reproducing device (100)
Sends a transmission request for a stream to be reproduced later to the transmission device (200), as long as the line bandwidth of the data transmission path allows regardless of the reproduction speed.

FIG. 3 shows a buffer section (130) incorporated in the receiving and reproducing apparatus (100). The buffer unit includes at least seven buffers, and each of the buffers depends on the timing to be used.
0), “write buffer” (230), “read buffer” (240), “playback buffer” (250), “empty buffer” (220), and “full buffer” (24).
5). In the first embodiment, the buffer after reception means that unplayed content is stored.
The buffer after writing and the buffer after reading are called "full buffers". "Free buffer" must be at least 2 for "receive buffer" and "read buffer".
I need a piece. During reception, when writing to one "receiving buffer" is completed, writing to the next "receiving buffer" must be started immediately.
Similarly, during reading, when writing to one "read buffer" is completed, writing to the next "read buffer" must be started immediately.

The reproducing unit (150), the receiving unit (120) and the caching disk unit (140) are connected to these seven buffers via a data bus (260). For convenience of explanation, inside the buffer part,
A description will be given by referring to a “reception buffer”, a “reproduction buffer”, a “read buffer”, a “write buffer”, a “full buffer”, and a “free buffer”. Actually, they are physically the same buffer. When each buffer performs the present invention, even though it is physically the same buffer, its role changes according to its timing, so such a term is used. In other words, it operates as a “reception buffer” when receiving, and operates as a “reproduction buffer” when it is reproduced.

The buffer unit stores a plurality of buffer data (3
00). FIG. 4 shows the components of each buffer data. The content section (310) contains continuous media
The content to be reproduced as a stream is stored.
The stream number section (350) stores an identification number given to the continuous media stream. The null identifier (320) indicates that the buffer is not a free buffer.
The fact that "1" is written in the write identifier section (330) indicates that the data is stored in the caching disk section (140), and that the reproduction identifier section (340) has already been reproduced. Express. When "0" is written, it means the opposite. The stream number and the contents of the buffer data (300) are stored in the caching disk unit.

FIG. 5 shows a continuous media stream (400) to be played. The continuous media stream (400) is partitioned by the same size as the size of the content (310) of the buffer data (300), and is assigned a stream number (410) in order. The separated section is a transmission unit transmitted from the transmission device (200). As an example of a continuous media stream (400), taking an 8-bit PCM 11 KHz audio stream, the number of bytes required to play the stream for about 5 minutes is about 3.14 Mbytes. In this embodiment, the buffer size is set to 8192 bytes.
Therefore, the total number of continuous streams is 403 (= 3.14)
× 1024 × 1024 / 8.192 + 2)
Individual. Hereinafter, the algorithm of the present invention will be described with reference to FIGS. 7A to 7F. FIG. 7A shows an overall flowchart in the first embodiment. After the user input, it operates as if the respective processes of the receiving step, the writing step, the reproducing step, the reading step, and the clearing step are performed in parallel.

(1) User input step (FIG. 7A) (a) The user inputs the type of media to be reproduced, the range, the number of buffers to be used, and other information from the user input unit. The controller specifies a number set of the content of the continuous media stream required for playback (hereinafter, referred to as a “playback set” in the present specification). (B) The caching disk unit is searched, and the number set of the contents stored in the caching disk unit in the “playback set” and not stored in the buffer unit (hereinafter “disc set”) (Called "set"). (C) In the “playback set”, a set of numbers of contents that are not included in the “disc set” and need to be transmitted by the transmission device to the transmission device and received by the reception and reproduction device "Received set" is specified. (D) A set of numbers of contents that are not included in the “disc set” in the “reproduction set” and that should be written to the caching disk unit (hereinafter “write set”)
).

(2) Reception step (FIG. 7B) (a) A content transmission request is transmitted to the transmission device in ascending order of the number in the “reception set”. (B) The content is received with the “empty buffer” as the “reception buffer”. Received content-> content section (310) (c) The following information is written in the "reception buffer" to become a "full buffer". The "full buffer" waits for the next processing, such as reproduction processing or writing processing. Stream number-> stream number part (350) "1" indicating that the buffer is not an empty buffer->
Null identifier (320) (d) Delete the number of the received content of the "received set" from the "received set".

(3) Reproduction Step (FIG. 7C) (a) Search for “full buffer” whose reproduction identifier is “0” in the “reproduction set” in ascending order of number. (B) The detected “full buffer” is replaced with the “playback buffer”
To reproduce the content stored therein. (C) Write the following information in the “reproduction buffer”. “1” indicating that the content has been reproduced—> reproduction identifier part (340) (d) The number of the content that has been reproduced in the “reproduction set” is deleted from the “reproduction set”. (E) If there is no "full buffer" storing the designated content, popular content (for example, the latest news, weather forecast, etc.) stored in the cache disk unit is interrupted beforehand for playback. to continue. However, when the specified content is received and stored in the buffer, the reproduction of the interrupted content is stopped, and the reproduction of the original content is resumed using the “full buffer” as the “reproduction buffer”.

(4) Write Step (FIG. 7D) (a) In the “write set”, search for “full buffer” whose write identifier is “0” in ascending order of the number. (B) The detected “full buffer” is set as the “write buffer”, and the content and the stream number of the information stored therein are written to the cache disk unit. (C) Write the following information in the “write buffer”. "1" indicating that writing has been completed-> write identifier section (330). (D) Delete the number of the written content of the “writing set” from the “writing set”. (5) Read Step (FIG. 7E) (a) Search in the “disk set” in ascending order of the number. (B) “empty buffer” is referred to as “read buffer”,
The detected content and stream number are read from the cache disk unit and stored in the “read buffer”. Read content-> content part (310) (c) The following information is written in the "read buffer" and is set as "full buffer". Stream number-> stream number part (350) "1" indicating that the buffer is not an empty buffer->
Null identifier (320) "1" indicating that writing has been completed-> write identifier (330). (E) The number of the read content of the “disc set” is deleted from the “disc set”.

(6) Buffer clear step (FIG. 7)
F) (a) If there is a buffer in the “full buffer” that has been written to the caching disk and has been played, the content and stream number are cleared, the next information is written, and the “free buffer” is written. I do. “0” —> null identifier section (320) indicating “empty buffer” — “0” —> reproduction identifier section (3
40) "0" indicating that data has not been written-> write identifier (330) (b) When there is no "empty buffer", caching
If there is a "full buffer" that has been written to the disk unit but has not been reproduced, its contents and stream number are cleared, and the next information is written as an "empty buffer". “0” —> null identifier section (320) indicating “empty buffer” — “0” —> reproduction identifier section (3
40) “0” indicating that there is no writing—> write identifier part (330) Here, the number of the content that has become the “empty buffer” is added to the “disc set”. If there are a plurality of "full buffers", the next information is written to the "full buffer" having the largest stream number among them, and the "full buffer" is written. “0” —> null identifier section (320) indicating “empty buffer” — “0” —> reproduction identifier section (3
40) “0” indicating that there is no writing—> write identifier part (330) Here, the number of the content that has become the “empty buffer” is added to the “disc set”. (7) Steps (1) to (6) are repeated until the end condition is satisfied, that is, the “reproduction set” and the “write set”
Repeat until is empty.

As shown in FIG. 7A, steps (1) to (6) are repeatedly executed, and the processes of the receiving step, the writing step, the reproducing step, the reading step, and the clearing step are performed in parallel. Works like that. By performing the receiving step, the writing step, the reproducing step, the reading step, and the clearing step in parallel, the following effects can be expected. That is, when there is room in the transmission path, a stream to be reproduced later can be received regardless of the reproduction speed and stored on the disc. Even when the user pauses the reproduction, for example, in a pause, the stream to be reproduced later is also received and stored on the disc. For this reason, even when the transmission path becomes overloaded during reproduction, a previously stored stream can be read from the disk to reproduce a high-quality continuous media stream. In the prior art, even if there is room in the transmission path, only the stream necessary for reproduction at that time can be received. Conversely, if the transmission line is overloaded, the quality of the continuous media stream will immediately degrade.

On the other hand, if the state of heavy load on the transmission path continues for a long time, all buffers may be emptied. In this case, in the conventional method, the reproduction is interrupted, and the user waits until the content is written in the “receiving buffer”. In the present invention, the popular content (for example, the latest news, weather forecast, etc.) cached in advance in the disk is played back by interrupting the current stream. In the meantime, reception is continued, and when contents to be originally reproduced specified by the user are accumulated to some extent, interruption of popular contents is stopped, and reproduction of the original contents is continued. When all buffers are emptied again, interrupting the popular content resumes. By repeatedly executing such interrupts, silence can be eliminated, and the quality of service provided can be improved.

The user can further specify various parameters for controlling the operation. For example, there is a designation of storing or not storing the reproduced content on a disc, a limitation of a used disc capacity, a designation of information to be reproduced at the time of interruption, and the like. When the mode for storing the received content on the disc is selected and the continuous media stream data is stored on the disc, it is needless to say that operations such as replay, fast forward, and rewind can be performed immediately.

[0022]

Embodiment 2 In another embodiment, the caching disk section (140) is removed from the configuration shown in Embodiment 1. FIG. 9 is a diagram illustrating the internal structure of the buffer unit according to the second embodiment. A receive buffer (610), a play buffer (620), a full buffer (640), and a free buffer (630) are shown. In the second embodiment,
Eight buffers are used. The size of the content of each buffer is 8192 bytes. As an example of a continuous media stream, taking an 8-bit PCM 11KHz audio stream, one buffer would have about 0.7
You can save seconds. Therefore, about 5.6 (= 0.7 × 8) seconds of audio data can be stored in eight empty buffers.
The user can arbitrarily specify the maximum number of buffers to be used. Since the system of the present invention can increase the number of buffers within the range specified by the user, it can flexibly cope with a light load on the transmission path.

FIG. 8 shows the components of the buffer data (500) in the second embodiment. The buffer data (500) in the second embodiment includes a content part (510), a state identifier part (520), and a buffer number part (53).
0). In the status identifier section (520), "0" is shown to indicate that the buffer is a free buffer, and "0" is shown to indicate that it is a full buffer.
1 "is written. (530) is written in the buffer number portion.
The number assigned to the buffer in the reproducing / receiving device is stored. In the second embodiment, since eight buffers are used, buffer data having buffer numbers from 0 to 7 is provided. FIG. 10A shows a flowchart in the second embodiment. The size of the buffer actually used for reception (the sum of the “reception buffer” and all “empty buffers”) and the size of the buffer used for playback (the sum of the “playback buffer” and all the “full buffers”) are not necessarily the same. Instead, it changes dynamically according to the status of the system. For example, if the receiving speed is faster than the playback speed, the full "receiving buffer" or "full buffer"
Increase the number of When the reproduction speed becomes faster than the reception speed, the number of buffers that have been reproduced and cleared, that is, “empty buffers” increases. Hereinafter, the algorithm of the second embodiment will be described with reference to FIGS. 10A to 10C.

(1) User input step (FIG. 10A) (a) The user inputs the type of media to be reproduced, the range, the number of buffers to be used, and other information from the user input unit. The controller specifies a continuous media stream required for reproduction and its range. (2) Transmission request step (a) A transmission request for transmitting a content in a specified range of the specified continuous media stream is sent to the transmitting device. The transmission unit of the content transmitted from the transmission device is the first embodiment.
Similarly, the size is the same as the size of the content part of the “receiving buffer”.

(3) Receiving step (FIG. 10B) (a) Search for a buffer having a number one greater than the buffer number of the buffer in which the previously received content has been written. However, when the buffer number reaches the maximum buffer number, a buffer having the minimum buffer number is searched. In the second embodiment, when the process reaches the maximum buffer number (7), the minimum buffer number (0) is searched. (B) If the buffer is an "empty buffer", the buffer is set as a "reception buffer" and the requested content is received. Received content-> content section (510) (c) Write the following information in the "reception buffer" and set it as "full buffer". Indicates a full buffer "
1 "-> Status Identifier (520) (d) When the buffer contains unreproduced content (when the status identifier is" 1 "), the reception is interrupted and the buffer becomes" 1 ". Wait until it becomes "free buffer".

(4) Reproduction Step (FIG. 10C) (a) Search for a buffer having a number one greater than the buffer number of the buffer containing the previously reproduced content. However, when the buffer number reaches the maximum buffer number, a buffer having the minimum buffer number is searched. In the second embodiment, when the process reaches the maximum buffer number (7), the minimum buffer number (0) is searched. (B) If the buffer is a "full buffer", set it as a "playback buffer" and read and play the content from there. (C) The content of the reproduced buffer is cleared, and the next information is written in the content to make it a “free buffer”. "0" indicating empty buffer-> status identifier section (520) (d) When no playback content is stored in the buffer (when the status identifier is "0"), playback is interrupted. Then, it waits until the unreproduced content is written in the buffer. (5) Repeat steps (2) and (4) in parallel until the specified range of the specified continuous media stream has been played.

[0027]

FIG. 6B shows the content transmission status according to the present invention. According to the present invention, the receiving unit receives the content to be reproduced later and stores it on a disc as long as the capacity of the transmission path permits, regardless of the reproduction speed. The same applies when the user instructs a temporary stop. FIG. 6A shows the state of transmission of content according to the related art. In the prior art, even if there is room in the capacity of the transmission path, only the necessary data is transmitted at that time. When the user instructs suspension, transmission of the content is interrupted. Therefore, the present invention can reduce the deterioration of the quality of the reproduction media due to the instability of the transmission path of the Internet when reproducing the continuous media such as audio and video on the Internet.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a conventional technique.

FIG. 2 is a block diagram showing a preferred embodiment of the present invention.

FIG. 3 is a diagram illustrating a buffer unit according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating buffer data according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a continuous stream according to the first embodiment of the present invention.

FIG. 6A is a diagram showing a data transmission state in the related art.

FIG. 6B is a diagram illustrating a data transmission state according to the present invention.

FIG. 7A is a flowchart relating to a preferred embodiment 1 of the present invention.

FIG. 7B is a detailed flowchart for a preferred embodiment 1 of the present invention;

FIG. 7C is a detailed flowchart for a preferred embodiment 1 of the present invention;

FIG. 7D is a detailed flowchart for a preferred embodiment 1 of the present invention;

FIG. 7E is a detailed flowchart for a preferred embodiment 1 of the present invention;

FIG. 7F is a detailed flowchart for a preferred embodiment 1 of the present invention.

FIG. 8 is a diagram showing buffer data according to the second embodiment of the present invention.

FIG. 9 is a diagram illustrating a buffer unit according to a second embodiment of the present invention.

FIG. 10A is a flowchart relating to a preferred embodiment 2 of the present invention.

FIG. 10B is a detailed flowchart for a preferred embodiment 2 of the present invention;

FIG. 10C is a detailed flowchart for a preferred embodiment 2 of the present invention.

[Explanation of symbols]

 100: Receiving / reproducing device 110: I / F unit 120: Receiving unit 140: Caching disk unit 130: Buffer unit 150: Reproducing unit 170: Controller unit 160: User input unit 180: Data transmission path 200: Transmitting device, 220: Transmission unit 230: Transmission data storage unit 212: I / F unit 222: Transmission unit 232: Transmission data storage unit 210, 610: Reception buffer 220, 630: Free buffer 230: Write buffer 240: Read buffer 245, 640: Full buffer 250, 620: playback buffer 260, 650: data bus 300, 500: buffer data 310, 510: content section 320: null identifier section 330: write identifier section 340: playback identifier section 350: stream number section 400: continuous media・ Stream 41 : Stream number 520: status identifier 530: buffer number portion

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04L 13/08 H04L 13/08 (72) Inventor Taro Sugawara 3-2-2 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Inside Packard Laboratories Japan Inc. (72) Inventor Junichi Yamazaki 3-2-2 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Hewlett-Packard Laboratories Japan Inc. F-term (reference) 5B065 BA01 CE12 CE14 CE16 CH03 EA33 5B089 GA21 JA22 JB02 JB03 JB05 JB12 JB24 KD01 KD02 KD05 KD07 KD09 KD10 KE02 KE03 KE09 LB13 LB14 LB25 ME10 5C064 BA07 BB05 BC10 BC20 BC25 5K028 AA01 EE03 KK03 KK32 MM12 5K03H02 H02H02 H24

Claims (20)

[Claims] 1. A system for playing back a continuous media stream transmitted from a transmitting device through a transmission path while receiving the continuous media stream at a receiving and reproducing device, wherein the transmitting device divides the continuous media stream into predetermined transmission units. The receiving / reproducing apparatus includes a receiving unit, a buffer unit, a caching disk unit, a reproducing unit, and a control unit, and includes the following units (a) to (k). Continuous media stream playback system,
(A) means for identifying a number set of content of the continuous media stream to be played (hereinafter referred to as a play set); (b) searching the caching disk unit;
Means for identifying a number set of contents stored in the caching disk unit in the reproduction set and not yet stored in the buffer unit (hereinafter referred to as a disk set); (C) A set of numbers of contents that are not included in the set of discs and that need to be transmitted to the transmitting device and received by the receiving and reproducing device (hereinafter referred to as a set of numbers). Means to identify the receiving set),
(D) means for specifying a set of content numbers which are not included in the disc set and which should be written to the caching disc unit (hereinafter referred to as a write set) in the reproduction set; Means for sending a transmission request to the transmission device in ascending order of the number in the reception set,
(F) means for receiving the requested content of the reception set by the reception unit and storing the content in the buffer unit; and (g) storing the content in the buffer unit in ascending order of the reproduction set. Means for playing the content, (h)
Means for writing the contents stored in the buffer unit to the cache disk unit in ascending order of numbers in the writing set; (i) storing the contents in the cache disk unit in ascending order of numbers in the disk set Means for reading from the unit and storing in the buffer unit;
(J) means for clearing a buffer that has been reproduced and a buffer for which data has been written, and opening the buffer for reception; (k) performing the operations from the means (e) to (j) in parallel, A means to repeat until the write set is empty. 2. A system for playing back a continuous media stream transmitted from a transmitting device through a transmission path while receiving the continuous media stream at a receiving and reproducing device, wherein the transmitting device divides the continuous media stream into predetermined transmission units. The receiving and reproducing apparatus has a receiving unit, a buffer unit, a reproducing unit, and a control unit, the buffer unit has a plurality of buffers, each buffer is at least a buffer number, A continuous media stream playback system having an identifier and content and including the following means (a) to (g): (a) specifying a range of the continuous media stream to be played back according to a user's instruction (B) sending a transmission request for the range of the continuous media stream to the transmitting device, and receiving the request by the receiving and reproducing device. (C) means for writing the received content into a buffer unit, wherein the means stores the received content and the full buffer in an empty buffer of the buffer unit in the order of the buffer number and in the circulating order. (D) means for reproducing the content of the buffer unit, wherein the means comprises:
The contents stored in the full buffer of the buffer unit are played back in the order of the buffer number in a young and circular order,
Clearing the contents of the full buffer in the buffer section reproduced, writing an identifier indicating that the buffer is empty, (e) processing means (c) and (d) in parallel, and Means for repeating until the reproduction of the specified range of the stream ends. 3. The means for writing the received content into the buffer unit interrupts the writing when the empty buffer does not exist, and the means for reproducing the content in the buffer unit reproduces the content when the full buffer does not exist. 3. The continuous media stream playback system according to claim 2, comprising interrupting. 4. The system according to claim 1, wherein said means for sending said transmission request to said transmission device further sends said transmission request to said transmission device independently of a reproduction speed or a reproduction state. A system characterized in that: 5. The system according to claim 1, wherein the transmission unit of the continuous media stream includes a numbered identifier, and the number of bytes of the content of the transmission unit is the number of bytes of the content of the buffer unit. A system characterized by the same number of bytes. 6. The system according to claim 2, wherein the number of bytes of the content in the transmission unit is the same as the number of bytes of the content of the buffer unit. 7. The system according to claim 1, wherein the means for clearing the buffer that has been reproduced and the buffer that has been written, and opening the buffer for reception, further has no buffer opened for reception. In this case, if there is a buffer that has been written on the caching disk unit but has not been reproduced, the buffer is cleared and opened for reception. A means for clearing the buffer and opening it for reception. 8. The system according to claim 1, wherein said means for playing back the content stored in said buffer unit further comprises: when said designated content is not stored in said buffer unit, A system comprising means for playing another content stored in a cache disk unit. 9. The system according to claim 1, wherein in the reception / reproduction processing of the continuous stream data, each buffer of the buffer unit includes at least a reception buffer for storing the received content, and the caching disk. A read buffer for storing buffer data read from the caching disk, a reproduction buffer for reproduction,
A system that operates as an empty buffer that is cleared after playback and a full buffer in which content is stored. 10. The system according to claim 1, wherein the buffer unit includes at least the content, the stream number, a null identifier indicating that the buffer is a free buffer, and a buffer already written on the caching disk. A system comprising a write identifier indicating that there is, and a playback identifier indicating that playback has been performed. 11. A method for playing back a continuous media stream transmitted from a transmitting device through a transmission path while receiving the continuous media stream at a receiving and reproducing device, wherein the transmitting device divides the continuous media stream into predetermined transmission units. The receiving and reproducing apparatus has a receiving unit, a buffer unit, a caching disk unit, a reproducing unit, and a control unit, and includes the following steps (a) to (k). Continuous media stream playback method,
(A) identifying a number set of contents of the continuous media stream to be played (hereinafter referred to as a play set); (b) searching the caching disk unit and searching the caching disk portion in the play set. Identifying a set of numbers of contents stored in the disk unit and not yet stored in the buffer unit (hereinafter referred to as a disk set);
(C) A set of numbers of contents that are not included in the set of discs and that need to be transmitted to the transmitting device and received by the receiving and reproducing device (hereinafter referred to as a set of numbers). (D) a set of contents that are not included in the disc set and that are to be written to the caching disc unit (hereinafter referred to as a write set). (E) sending a transmission request to the transmitting device in ascending order of the number in the reception set; (f) receiving the requested content of the reception set by the reception unit; (G) playing the content stored in the buffer unit in ascending order of the number in the playback set; h) the ascending order of numbers in the write set, writing the content stored in the buffer unit to the cache disk unit,
(I) reading contents from the cache disk unit in ascending order of numbers in the disk set and storing the contents in the buffer unit; (j) clearing if there is a reproduced buffer and a written buffer (K) performing the above-mentioned steps (e) to (j) in parallel and repeating until the reproduction set and the write set become empty. 12. A method for playing back a continuous media stream transmitted from a transmitting device via a transmission path while receiving the continuous media stream at a receiving and reproducing device, wherein the transmitting device divides the continuous media stream into predetermined transmission units. The receiving and reproducing apparatus has a receiving unit, a buffer unit, a reproducing unit, and a control unit, the buffer unit has a plurality of buffers, each buffer is at least a buffer number, A method for playing back a continuous media stream having an identifier and content and including the following steps (a) to (g): (a) specifying a range of the continuous media stream to be played back according to a user's instruction (B) sending a transmission request for the range of the continuous media stream to the transmitting device and receiving the request by the receiving and reproducing device. Step (c) writing the received content into the buffer unit, wherein the received content and the full buffer are stored in the free buffer of the buffer unit in the order of the buffer number and in the circulating order. Write an identifier indicating that
(D) playing the content of the buffer unit, wherein the step plays back the content stored in the full buffer of the buffer unit in the chronological order of the buffer numbers, and Clearing the contents of the full buffer of the part, writing an identifier indicating that the buffer is empty, (e) performing steps (c) and (d) in parallel, and specifying the specified continuous media stream. Repeating until the reproduction of the selected range is completed. 13. The step of writing the received content into a buffer unit, the method comprising:
13. The continuous media stream playback method according to claim 12, wherein stopping the writing and playing back the content of the buffer unit includes stopping the playback when the full buffer does not exist. 14. The method according to claim 11, wherein the step of sending the transmission request to the transmitting device comprises:
The method further comprises sending the transmission request to the transmitting device independently of a reproduction speed or a reproduction state. 15. The method according to claim 11, wherein the transmission unit of the continuous media stream includes a numbered identifier, and the number of bytes of the content of the transmission unit is the number of bytes of the content of the buffer unit. A method characterized by having the same number of bytes. 16. The method according to claim 12, wherein the number of bytes of the content of the transmission unit is the same as the number of bytes of the content of the buffer unit. 17. The method according to claim 11, wherein the step of clearing the buffer that has been reproduced and the buffer that has been written, if any, and releasing the buffer for reception, further comprises no buffer released for reception. In this case, if there is a buffer that has been written on the caching disk unit but has not been reproduced, the buffer is cleared and opened for reception. Clearing the buffer and opening it for reception. 18. The method according to claim 11, wherein the step of reproducing the content stored in the buffer unit is further performed when the designated content is not stored in the buffer unit. cache·
Playing a different content stored on the disc unit. 19. The method according to claim 11, wherein in the process of receiving and reproducing continuous stream data, each buffer of the buffer unit comprises at least a receiving buffer for storing the received content, and the caching disk. A read buffer for storing buffer data read from the caching disk, a reproduction buffer for reproduction,
A method of operating as a free buffer that is cleared after playback and a full buffer in which content is stored. 20. The method according to claim 11, wherein the buffer unit includes at least the content, the stream number, a null identifier indicating that the buffer is a free buffer, and a buffer already written on the caching disk. A method comprising: including a write identifier indicating presence and a playback identifier indicating playback.