JP2008103972A - Network video recording and reproduction system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network video recording and reproduction system capable of starting to download at a client device side without waiting for a server device side to complete video recording and performing stabled video record reproduction by following even a change in a communication speed. <P>SOLUTION: The server device 200 has a buffer means (205 and 206) for converting received content data into stream data and stores the stream data time sequentially, and a transmitting means (208 and 209) for transmitting the stored content stream data to a network 280 in the stored order. A client device has a receiving means for receiving content stream data through the network, a storing means for storing the received content stream data in a recording medium time sequentially, and a reproducing means for reproducing the content stream data recorded on the recording medium in a storing order. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a network recording / reproducing system for recording and reproducing contents such as television broadcasts received at a remote place via a network.

  In recent years, home server devices that record video / audio signals on digital recording media such as HDDs and DVDs have become widespread, and home server devices at home from mobile terminals on the go by streaming distribution function using the Internet or the like. It is also possible to view the recorded content. For example, in the “television broadcast recording service server device” disclosed in Patent Document 1, a requested program is recorded on the server device side, and the recorded content is streamed or downloaded via the Internet. A viewing system has been proposed.

  However, in the above system, it is assumed that the program that the user wants to watch is recorded once. After the recording is completed, the recorded content is downloaded and viewed on a PC or the like via the Internet. There was a problem of long waiting time. In the above system, means for streaming delivery has also been proposed. However, streaming delivery has a problem that the image quality of the viewed video is deteriorated in an environment where the Internet communication speed is low.

  6A and 6B are diagrams for explaining an example of a conventional network recording / playback system (network recording system). FIG. 6A shows a configuration example on the server device side, and FIG. 6B shows a configuration example on the client device side. It is. 6A and 6B, an outline of a conventional method of recording a broadcast program (content) on the server device side, and downloading and recording the recorded content on the client device side via a network such as the Internet. Will be explained.

  First, a procedure on the client device 150 side that requests content to be recorded on the server device 100 side will be described. When the client device 150 is operated to record the specified content (specified program) by the user operation 160, the user operation execution unit 158 generates a command for remotely operating the server device 100. The generated command is transmitted to the server apparatus 100 via the network 180 by the command transmission unit 157. In this communication, communication is performed using TCP / IP (Transmission Control Protocol / Internet Protocol) which is a commonly used protocol.

  In this operation, the client device 150 is equipped with a web browser, the server device 100 starts a remote web server, and the server device 100 is remotely operated from the client device 150 via the web browser. However, description of the operation method is omitted. 6A is received by the command reception unit 111 of the server device 100 via the network 180, and the received command is passed to the command execution unit 110. The command execution unit 110 determines that it is a recording start request, and instructs the recording control unit 107 to start recording. The recording control unit 107 performs control according to the following procedure in order to record content specified by the user.

  First, in order to select a program content to be received by the antenna 101, the tuner unit 102 is controlled to perform tuning. The content received by the tuner unit 102 is converted into digital video data by the NTSC decoder unit 103 in accordance with, for example, the NTSC (National Television Standards Committee) system which is one of standardized broadcasting systems. Precisely, the analog signal output from the tuner unit 102 is digitized by an A / D converter, and the NTSC decoder unit 103 performs ITU-R BT. It is converted into digital video data conforming to the 656 standard. When the tuner unit 102 is a digital tuner, the NTSC decoder unit 103 is not necessary.

Next, for example, the digital video data is compressed into MPEG (content) stream data by the MPEG encoder unit 104 based on, for example, the MPEG (Moving Picture Experts Group) system whose video data compression system is being standardized. Note that MPEG2, MPEG4, H264, WMV, VP5, and the like are used as compression methods used in the MPEG encoder unit 104.
The generated video stream data is converted into a file format determined by the stream recording control unit 105 and is stored and saved in a recording data storage unit (HDD) 106. As a file format at this time, MPG, AVI, ASF, MP4, WMV, etc. are common. In this manner, recording of the designated program is started on the server device 100 side by remote operation.

  Next, a procedure for downloading content recorded by the server apparatus 100 of FIG. 6A to the client apparatus 150 of FIG. 6B will be described. When the user operation execution unit 158 is operated to download the specified recorded content by the user operation 160 in the client device 150, a command for remotely operating the server device 100 is generated, and the command transmission unit 157 A command is transmitted to the server apparatus 100 via the network 180. The command transmitted to the server apparatus 100 is received by the command receiving unit 111 on the server apparatus side 100 via the network 180, and the received command is passed to the command execution unit 110. The command execution unit 110 determines that the request is a download request, and instructs the transmission control unit 108 to start downloading.

  The transmission control unit 108 reads designated recording content data stored in the recording data storage unit 106, passes it to the recording data transmission unit 109, and transmits it to the client device 150 via the network 180. In the client device 150, when the user operation 160 is operated to download the recorded content specified by the user operation 160, the user operation execution unit 158 downloads the specified recorded content to the recorded data storage control unit 155 via the network 180. Instructions are given.

  In response to this instruction, the recorded data storage control unit 155 downloads the recorded content transmitted from the server device 100. First, the recorded data receiving unit 151 sequentially receives the recorded content data transmitted from the server device 100 via the network 180. The received recorded content data is sequentially stored in the recorded data storage unit 152. Finally, the recorded content data is stored in the recorded data storage unit 152, and the download is completed. In this download process, download is performed by a general FTP (File Transfer Protocol) protocol as a file transfer protocol.

  In this way, the recorded content recorded on the server device 100 side is downloaded to the client device 150 side and played back and viewed. As the playback procedure, the user operation 160 is operated to view the downloaded recorded content, and the user operation execution unit 158 instructs the playback control unit 156 to play back the downloaded recorded content. The reproduction control unit 156 reproduces the recorded content downloaded in the following procedure.

That is, the recorded content data downloaded from the recorded data storage unit 152 is read out and transferred to the MPEG decoder unit 153 as compressed video stream data. In the MPEG decoder unit 153, the compressed video stream data is converted into ITU-R BT. Convert to digital video data conforming to the 656 standard. The decoded digital video data is converted into an NTSC analog signal by the NTSC encoder unit 154 and output to the monitor unit 159. In this way, the recorded content downloaded to the client side 150 is reproduced.
JP 2003-319363 A

  However, in the above-described conventional method, when the user wants to view the content broadcast on the client device 150 side, the content is once recorded on the server device 100 side, and after the recording is completed, the content is again transmitted via the network. It is necessary to download the recorded content downloaded to the client device 150 after downloading the recorded content to the client device 150 and completing the download. That is, in order to view the content received by the home server device at a remote location, the content received by the home server device is once recorded. Thereafter, the content recorded by the home server device is downloaded to the client device via the network, and the content downloaded to the client device is reproduced and viewed. For this reason, the waiting time until the specified content can be viewed is very long, and the efficiency is low.

  In addition, the video received by the server-side device 100 is streamed and distributed over the network in real time using RTP (Real-time Transport Protocol) / RTSP (Real Time Streaming Protocol), thereby reducing the waiting time. However, in this case, there is a problem that the image quality of the viewed video is deteriorated in an environment where the network communication speed is low.

  The present invention has been made in view of the above-described circumstances, and can download on the client device side without waiting for the recording to be completed on the server device side, and can follow changes in communication speed. An object of the present invention is to provide a network recording / playback system that can perform stable recording / playback.

  The network recording / playback system according to the present invention is a network recording / playback system comprising a server device having a function of distributing received content data and a client device for storing the content data in a recording medium via a network. The server device has buffer means for converting received content data into stream data and storing the data in time series, and transmission means for transmitting the stored content stream data to the network in the order in which they are stored. The client device includes: a receiving unit that receives content stream data via a network; a storage unit that stores the received content stream data in a time-sequential order in a recording medium; and the order in which the content stream data recorded in the recording medium is stored Reproducing means for reproducing is provided. A ring buffer can be used as the buffer means of the server device.

  In addition, the client device includes a recording time length notifying unit that notifies the server device of information on a recording time length, and the server device includes a buffer capacity detecting unit that detects a remaining capacity of the recording medium of the buffer unit. A communication speed detecting means for detecting a network communication speed, a bit rate calculating means for calculating a bit rate of content stream data recordable on the client device side based on a recording time length notified from the client device, and a calculation Transmission means for generating the content stream data at the bit rate and transmitting it to the network can be provided. Furthermore, a timer processing means for periodically performing the bit rate calculation by the bit rate calculating means may be provided.

  The client device includes a reproduction time length monitoring unit that detects a reproduction time length of the content stream data stored in the storage unit, and a time in which the reproduction time length detected by the reproduction time length monitoring unit is designated by the user. When the length has been reached, the content stream data stored in the storage means may be decoded and played back, and a standby state may be entered when playback ends.

  According to the present invention, the contents received on the server device side in different locations are sequentially recorded on the client device side via the network, so that the client does not have to wait for the recording to be completed on the server device side. It is possible to efficiently record and reproduce on the apparatus side. In addition, even if the network communication speed fluctuates or does not reach the required communication speed, stable recording can be continued by appropriately adjusting the buffer capacity and bit rate of the server device. Can do.

Embodiments of the present invention will be described with reference to the drawings. 1A and 1B are diagrams for explaining the first embodiment, FIG. 1A shows a configuration example on the server device side, FIG. 1A shows a stream buffer image of the server device, and FIG. FIG. 3 is a diagram illustrating a configuration example on the client device side.
The network recording / playback system of the present invention includes a server device 200 having a function of distributing video content input or received via the broadcast radio wave shown in FIG. 1A as a video stream data on a network such as the Internet, and FIG. 1B. The client apparatus 250 is configured to record and store video stream data received via the network shown in FIG.

  The server device 200 is configured as buffer means by converting video content (hereinafter simply referred to as content) composed of input and received video and audio data or the like into video stream data (hereinafter simply referred to as stream data). Are temporarily stored in the recording medium in time series. The stream data stored in the recording medium is read out in a first-in first-out (FIFO) order in the order of storage, and is transmitted to the client apparatus 250 via the network 280. The client device 250 sequentially receives the stream data transmitted from the server device 200 via the network 280, stores the stream data in a time series in the recording medium, and sequentially decodes and reproduces the data.

Next, the embodiment shown in FIGS. 1A and 1B will be described with reference to an operation procedure in which designated content requested from the client apparatus 250 is received by the server apparatus 200 and transmitted to the client apparatus 250 as stream data.
In this operation, the client device 250 includes a web browser, for example, and the server device 200 activates a web server for remote operation, and the server device 200 is remotely connected from the client device 250 via the web browser. Manipulate.

  First, the client device 250 is operated by the user operation 260 to record the specified content (specified program). Thereby, the user operation execution unit 258 generates a command for remotely operating the server device 200, and the command transmission unit 257 transmits the command to the server device 200 via the network 280. In this communication, communication is performed using a general TCP / IP protocol. The command transmitted to the server device 200 is received by the command receiving unit 211 of the server device 200 via the network 280, and the received command is passed to the command execution unit 210. The command execution unit 210 determines that it is a recording start request, and instructs the recording control unit 207 to start recording.

  In the recording control unit 207, in order to record the content specified by the user, the tuner unit 202 is controlled and tuned to select the content of the program received by the antenna 201. The content received by the tuner unit 202 is converted into digital video data by the NTSC decoder unit 203 using, for example, NTSC, which is one of the broadcasting systems, as described with reference to FIG. 6A. That is, the analog signal output from the tuner unit 202 is digitized by an A / D converter, and the NTSC decoder unit 203 performs ITU-R BT. It is converted into digital video data conforming to the 656 standard. When the tuner unit 202 is a digital tuner, the NTSC decoder unit 203 is not necessary.

  Next, for example, as described with reference to FIG. 6A, the digital video data is compressed into stream data by the MPEG encoder unit 204 based on the MPEG method or the like. Note that MPEG2, MPEG4, H264, WMV, VP5, or the like can be used as a compression method used in the MPEG encoder unit 204. The generated stream data is stored in the stream buffer unit (HDD) 206 under the control of the buffer control unit 205 serving as a buffer unit.

  As shown by the buffer image 220 in FIG. 1A (b), the stream data at this time is stored in time series by alternately repeating video data 222 and audio data 223 in order from the buffer start position 221. The buffer storage direction is stored from the direction of the buffer start position 221 toward the right as indicated by 224. There are various ways of distributing the video data 222 and the audio data 223, but basically, the data encoded at the same time are arranged in pairs.

  Next, at the same time that the stream data starts to be stored in the stream buffer unit 206, the buffer control unit 205 notifies the transmission control unit 208 to transmit the stream data to the client device 250. The transmission control unit 208 reads the stream data from the stream buffer unit 206, passes it to the stream data transmission unit 209, and transmits it to the client device 250 via the network 280. At this time, as shown in the stream buffer image 220, the transmission control unit 208 sequentially reads from the buffer start position 221 toward the right side, but does not overtake the position stored in the buffer control unit 205 and read it. Control. In this way, content stream data is transmitted from the server device 200 to the client device 250 by remote operation.

Next, an operation procedure until the client apparatus 250 in FIG. 1B receives and views the stream data transmitted from the server apparatus 200 in FIG. 1A will be described.
When the client device 250 is operated to record content by the user operation 260, the user operation execution unit 258 issues a recording request to the server device 200, and at the same time, the network 280 is connected to the stream data storage control unit 255. The stream data is controlled to be received from the server apparatus 200 via the server apparatus 200.

  The stream data storage control unit 255 controls the stream data reception unit 251 to receive the stream data transmitted from the server device 200 via the network 280 and store it in the stream data storage unit 252. The stored image at this time is the same as the stream buffer image 220 shown in FIG. 1A (b), and the video data 222 and the audio data 223 are stored in order from the buffer start position 221 toward the right side. In this way, the stream data transmitted from the server device 200 is stored in the client side 250.

  Next, an operation procedure for reproducing and viewing the stream data stored in the client apparatus 250 of FIG. 1B will be described. When the client device 250 is operated to view the stored stream data by the user operation 260, the user operation execution unit 258 issues an instruction to reproduce the stream data stored in the reproduction control unit 256.

  The reproduction control unit 256 reads the stream data from the stream data storage unit 252 and passes it to the decoder unit 253. The MPEG decoder unit 253 converts the compressed stream data into, for example, ITU-R BT. Convert to digital video data conforming to the 656 standard. The decoded digital video data is converted into an analog signal by the NTSC encoder unit 254 and output to the monitor unit 259. In this way, the stream data stored in the client device 250 is reproduced. That is, it is not necessary to wait until all the stream data is completely stored in the stream data storage unit 252 in the client device 250, and the client apparatus 250 can reproduce and view from the stored portion.

  By doing so, the server apparatus 200 at a remote location can start storing while receiving the content in the stream buffer unit 206 and at the same time start transmitting to the client side 250. Thereby, there is no waiting time until recording starts in the client device 250, and further, playback and viewing can be performed up to the portion that can be stored even during recording in the stream data storage unit 252 of the client device 250. An efficient network recording / playback environment can be provided.

2A and 2B are diagrams for explaining the second embodiment. FIG. 2A shows a configuration example on the server device side, and FIG. 2B shows a ring buffer image of the server device. It is assumed that the client device has the same configuration as described in FIG. 1B.
The server apparatus 300 according to the second embodiment is different from the first embodiment in that a large-capacity ring buffer is used as a recording medium as the buffer means described in FIG. 1A.

  2A, the command transmitted from the client device to the server device 300 is received by the command receiving unit 311 of the server device 300 via the network 380, and the received command is passed to the command execution unit 310. . The command execution unit 310 determines that it is a recording start request, and instructs the recording control unit 307 to start recording. In the recording control unit 307, in order to record the content designated by the user, the tuner unit 302 is controlled and tuned in order to select the content of the program received by the antenna 301.

  The content received by the tuner unit 302 is converted into stream data by the MPEG encoder unit 304 via the NTSC decoder 303, and the ring buffer control unit 305 stores the content in the ring buffer unit 306, as in FIG. 1A. Store stream data. At the same time that the stream data starts to be stored in the ring buffer unit 306, the ring buffer control unit 305 requests the transmission control unit 308 to transmit the stored stream data to the network 380.

  In response to this request, the transmission control unit 308 reads the stream data stored from the ring buffer unit 306 and transmits the stream data to the network 380 by the stream data transmission unit 309. The storage and access to the ring buffer unit 306 at this time will be described with reference to the ring buffer image 320 in FIG.

  In writing the stream data to the ring buffer, first, the writing of the stream data is started from the buffer start position 321 and sequentially written toward the right side. Assuming that the time when a certain amount of time has passed in this way is now, the current data write position is the position indicated by 323. When the time further elapses, data writing proceeds in accordance with the data writing direction indicated by 327. At this time, if the data write position 323 has advanced to the buffer end position 324, the data write position 323 returns to the buffer start position 321 and continues writing.

  The reading of the content data from the ring buffer is the same as the writing. First, the reading of the stream data is started from the buffer start position 321 and is sequentially read toward the right side. Assuming that the time when a certain amount of time has passed in this way is now, the current data reading position is the position indicated by 322. When the time further elapses, data reading proceeds according to the data reading direction 326. That is, data is read as if the data writing position 323 is followed.

  That is, an area sandwiched between the current data reading position 322 and the current data writing position 323 becomes the data 325 currently stored in the buffer. The read position 322 is the same as the write operation, and when the data advances to the buffer end position 324, the data read position 322 returns to the buffer start position 321 and continues reading. At this time, when the capacity of the currently buffered data 325 becomes 0, the transmission control unit 308 controls to wait for the reading of the stream data, and the capacity of the currently buffered data 325 becomes the ring buffer. When the entire capacity is used up, the ring buffer control unit 305 controls to wait for the writing of stream data.

  As described above, even if the communication speed of the network 380 or the like varies due to the use of the ring buffer and the communication speed necessary for sending the stream data in real time may not be satisfied, the server apparatus 300 is mounted. As long as the ring buffer capacity permits, the recording by the client device can be continued.

3A and 3B are diagrams for explaining the third embodiment. FIG. 3A shows a configuration example on the server device side, and FIG. 3B shows a bit rate calculation method. It is assumed that the client device has the same configuration as described in FIG. 1B.
The server device 400 according to the third embodiment includes a buffer capacity detection unit, a network communication speed detection unit, a bit rate calculation unit, and a designation from the client device side to the server device side. This is different from the first embodiment in that a means for notifying the recording time length of the content is provided.

  In FIG. 3A, a command transmitted from the client device to the server device 400 is received by the command receiving unit 411 of the server device 400 via the network 480, and the received command is passed to the command execution unit 410. . The command execution unit 410 determines that it is a recording start request, and instructs the recording control unit 407 to start recording. In the recording control unit 407, in order to record the content designated by the user, the tuner unit 402 is controlled and tuned in order to select the content of the program received by the antenna 401.

  As in the case of FIG. 1A, the content received by the tuner unit 402 is converted into stream data by the MPEG encoder unit 404 via the NTSC decoder 403 and then streamed under the control of the buffer control unit 405 serving as buffer means. It is stored in a buffer unit (HDD) 406. At the same time that the stream data starts to be stored in the stream buffer unit 406, the buffer control unit 405 notifies the transmission control unit 408 to transmit the stream data to the client device. The transmission control unit 408 reads the stream data from the stream buffer unit 406, passes it to the stream data transmission unit 409, and transmits it to the client device via the network 480.

  In the server device 400, when the command receiving unit 411 receives a command to start recording, information on the recording time length is also received. The recording time length at this time is the broadcast time length of the content designated for recording by the user. This recording time length information may be notified from the client device, or the server device 400 may have a web server function. , And the program guide (EPG) information is acquired there, and the content of the reserved program may be designated from the client device via the web browser.

The information on the recording time length acquired by the server device 400 is passed to the bit rate calculation unit 413 as a bit rate calculation means in the command execution unit 410, where a request for calculating a necessary recording bit rate is issued. The bit rate calculation unit 413 issues a request to a communication speed detection unit 414 as a communication speed detection unit that detects information necessary for calculation and a buffer capacity detection unit 412 as a buffer capacity detection unit.
The communication speed detection unit 414 obtains the current communication speed information of the network 480 by detecting the data communication amount per unit time in the stream data transmission unit 409. Then, the obtained communication speed information is passed to the bit rate calculation unit 413.

The buffer capacity detection unit 412 detects the remaining capacity of the recording medium that can be used by the stream buffer unit 406, and passes the detected buffer capacity information to the bit rate calculation unit 413. The bit rate calculation unit 413 calculates the maximum recordable bit rate from the information of the detected recording time, communication speed, and buffer capacity.
The calculation method at that time can be calculated using the calculation formula shown in FIG. When the calculated bit rate satisfies the recording bit rate specified by the user, the bit rate calculation unit 413 notifies the recording control unit 407 to execute the recording process as usual because there is no particular problem.

However, if the recording bit rate specified by the user is not reached, the recording control unit 407 is notified that the recording processing is performed within the calculated bit rate. In the recording control unit 407, when notified from the bit rate calculation unit 413 to lower the recording bit rate, the recording control unit 407 controls the MPEG encoder unit 404 so as to perform encoding at a specified bit rate. To do.
As described above, when the communication speed of the network 480 is low and the buffer capacity of the recording medium mounted on the server device 400 is insufficient, the recording bit rate is controlled so as not to exceed the buffer capacity of the stream buffer unit 406. By adjusting, buffer overflow can be prevented and recording by the client device can be continued stably.

  FIG. 4 is a diagram for explaining another example of the third embodiment. In this embodiment, in the embodiment of FIG. 3 described above, the recording time length information acquired by the command reception unit 411 is transmitted from the command execution unit 410 via the regular timer processing unit 415 as a timer processing unit, to the bit rate calculation unit 413. The only difference is that it is passed to Since other configurations are the same as those in FIG. 3, description thereof is omitted by using the same reference numerals.

In the regular timer processing unit 415, the information on the recording time length is passed to the bit rate calculation unit 413 as it is for the first time to notify the calculation of the recording bit rate, but thereafter, from the specified recording time length every fixed period. The time information obtained by subtracting the elapsed time is passed to the bit rate calculation unit 413, and the process is repeated so as to periodically recalculate the recording bit rate. This fixed period is for making the recording bit rate follow the change in the communication speed of the network 480, and may be performed at intervals of about several minutes, for example.
In this way, by calculating and controlling the recording bit rate at regular intervals, the recording bit rate can be tracked even when the network communication speed changes according to time. Recording can be continued stably.

  FIG. 5 is a diagram showing another configuration example of the client device side in the first to third embodiments described above. The example of the client device is different from the configuration of FIG. 1B in that it includes a reproduction time monitoring unit that monitors the reproduction time length of the stream data stored in the storage unit. When the reproduction time length of the stored stream data reaches the specified time length, the reproduction time monitoring means starts to play the stream data and waits until it reaches the reproduction time length again when it finishes. is there. Since other configurations are the same as those in FIG. 1, detailed description is omitted by using the same reference numerals.

  When the client device 270 is operated to record the designated content by the user operation 260, the stream data storage control unit 255 is controlled to store the stream data, and at the same time, the designated reproduction time length information is The data is transferred to a reproduction time length monitoring unit 261 as reproduction time monitoring means. The reproduction time length is that the stream data is stored in the stream data storage unit 252 until the reproduction time length when the stream data stored in the stream data storage unit 252 is reproduced becomes the reproduction time length specified by the user. It is the designation information for.

  The playback time length monitoring unit 261 monitors the playback time length of the stream data stored in the stream data storage unit 252, and controls the playback control unit 256 when the specified playback time length is reached to Control is performed to reproduce the stream data stored in the data storage unit 252. The reproduction control unit 256 continues reproduction until all the stream data stored in the stream data storage unit 252 is reproduced, and enters a state of waiting for reproduction when the reproduction is completed. The playback time length monitoring unit 261 monitors the playback time length of the stream data stored in the stream data storage unit 252, and controls to play back to the playback control unit 256 when the playback time length specified by the user is reached. Repeat the process.

  As a method for monitoring the reproduction time length of the stream data stored in the stream data storage unit 252, for example, the time stamp information is engraved in the stream data. It is possible to use a detection method or a method of calculating an approximate reproduction time length by dividing the recording bit rate from the stored data size. In this way, when the content being recorded can be recorded up to a specified time length, by automatically starting the reproduction, the recorded content can be reproduced with a minimum waiting time.

It is a figure which shows the structural example of the server apparatus in the 1st Embodiment of this invention. It is a figure which shows the structural example of the client apparatus in the 1st Embodiment of this invention. It is a figure which shows the structural example of the server apparatus in the 2nd Embodiment of this invention. It is a figure which shows the structural example of the server apparatus in the 3rd Embodiment of this invention. It is a figure which shows the other example of the server apparatus in the 3rd Embodiment of this invention. It is a figure which shows the other structural example on the client apparatus side in the 1st-3rd embodiment of this invention. It is a figure which shows the example of the server apparatus of the conventional network recording / reproducing system. It is a figure which shows the example of the client apparatus of the conventional network recording / reproducing system.

Explanation of symbols

200, 300, 400 ... server device, 250, 270 ... client device, 201, 301, 401 ... antenna, 202, 302, 402 ... tuner unit, 203, 303, 403 ... decoder unit, 204, 304, 404 ... encoder, 205, 405 ... Buffer control unit, 305 ... Ring buffer control unit, 206, 406 ... Stream buffer unit, 306 ... Ring buffer unit, 207, 307, 407 ... Recording control unit, 208, 308, 408 ... Transmission control unit, 209 , 309, 409 ... stream data transmission unit, 210, 310, 410 ... command execution unit, 211, 311, 411 ... command reception unit, 412 ... buffer capacity detection unit, 413 ... bit rate calculation unit, 414 ... communication speed detection unit 415: Periodic timer processing unit, 251: Stream data Data receiving unit, 252 ... Stream data storage unit, 253 ... Decoder unit, 254 ... Encoder unit, 255 ... Stream data storage control unit, 256 ... Reproduction control unit, 257 ... Command transmission unit, 258 ... User operation execution unit, 259 ... Monitor unit, 260 ... user operation, 261 ... reproduction time length monitoring unit, 280, 380, 480 ... network.

Claims (5)

A network recording / playback system comprising a server device having a function of distributing received content data and a client device that stores the content data in a recording medium via a network,
The server device includes buffer means for converting the received content data into stream data and storing the content data in time series, and transmission means for transmitting the stored content stream data to the network in the order stored.
The client device includes a receiving unit that receives the content stream data via the network, a storage unit that stores the received content stream data in a recording medium in time series, and the content stream stored in the recording medium A network recording / reproducing system comprising decoding / reproducing means for decoding and reproducing data in the order in which they are stored.   2. The network recording / playback system according to claim 1, wherein a ring buffer is used as the buffer means of the server device. The client device includes a recording time length notification means for notifying the server device of information on a recording time length,
The server device includes a buffer capacity detecting unit for detecting a remaining capacity of the recording medium of the buffer unit, a communication speed detecting unit for detecting a network communication speed, and recording time length information notified from the client device. A bit rate calculating means for calculating the bit rate of the content stream data recordable by the client device, and a transmitting means for generating the content stream data at the calculated bit rate and transmitting it to the network. The network recording / playback system according to claim 1 or 2, characterized in that:   4. The network recording / reproducing system according to claim 3, further comprising timer processing means for periodically calculating a bit rate by the bit rate calculating means.   The client device includes a reproduction time length monitoring unit that monitors a reproduction time length of the content stream data stored in the storage unit, and the reproduction time length detected by the reproduction time length monitoring unit is a time specified by a user. The content stream data stored in the storage means is decoded and reproduced when the length is reached, and a standby state is set when the reproduction is completed. The network recording and playback system described.

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