JP5141060B2 - Data stream reproducing apparatus and data stream decoding apparatus - Google Patents

Description

  The present invention relates to a data stream reproducing apparatus and a data stream decoding apparatus for decoding and reproducing a broadcast or recorded data stream.

  Currently, new compression formats have been proposed one after another along with the development of encoding methods. For example, there are MPEG-2, MPEG-4, H.264, etc. as compression formats for handling video data, and MPEG-1 Layer3, Dolby Digital AC-3, DTS- as compression formats for handling audio data. HD etc. exist. Content creators can use these various types of compression formats depending on the purpose / purpose and type of recording medium (DVD, Blu-ray Disc (registered trademark), etc.).

  For example, in the Blu-ray Disc Read Only Format, as described in Non-Patent Document 1 below, MPEG-2 Video, H.264 AVC, VC-1 (MS), etc. are used as video data compression formats. As the compression format of audio data, the content creator arbitrarily selects various data streams including Dolby Digital AC-3, DTS, Dolby Digital Plus, DTS HD, etc. according to the purpose and purpose. Each data stream can be multiplexed according to the MPEG-2 TS (transport stream) format as defined in 2 and recorded as a multiplexed stream.

  However, in order for a playback apparatus to play back a multiplexed stream in which data streams of various compression formats are multiplexed, a decoder capable of decoding all the selectable compression formats It is necessary to have.

  Further, in order to play back and view different types of recording media (DVD, Blu-Ray, etc.), the user generally purchases a playback device corresponding to the type of each recording medium. At this time, although the data streams compressed in the same compression format are recorded on different types of recording media, a decoder for decoding the data stream in the same compression format is provided in each playback device. Will be provided. As a result, each playback device is provided with a decoder corresponding to a specific compression format, which causes a disadvantage to the user due to an increase in cost or the like.

The above problem can be solved by using decoders of various compression formats as much as possible between devices. For example, in the following Patent Document 1, in a system having a plurality of digital AV devices, video and audio are individually decoded between AV devices, and time information at the time of decoding processing is exchanged, whereby video And a technology that enables synchronized audio output.
JP 2001-128167 A (paragraphs 0019-0027) White paper Blu-ray Disc Format 2.B Audio Visual Application Format Specifications for BD-ROM March 2005, Reference URL: http://www.blu-raydisc.com/assets/downloadablefile/2b_bdrom_audiovisualapplication_0305-12955.pdf ITU-T recommendation H.222.0, "Information technology-Generic coding of moving pictures and associated audio information: systems"

  However, according to the technique described in Patent Document 1 above, two AV devices exist at a distance, for example, when two AV (Audio-Visual) devices are installed in different rooms. In this case, since the place (room) where the synchronization is output is different, the usefulness of the synchronized playback is not sufficiently realized. In addition, since it is necessary for the user to recognize what compression format is decoded and output by which AV device, there arises a problem that the connection between the AV devices becomes complicated.

  In order to solve the above problem, the present invention provides decoding of a data stream, even when a data stream that cannot be decoded by the playback device is multiplexed in a multiplexed stream played back by the playback device. It is an object of the present invention to provide a data stream reproduction device and a data stream decoding device capable of realizing synchronous reproduction of a data stream that does not give the user a sense of incongruity.

In order to achieve the above object, according to the present invention, there is provided a data stream reproducing device for reproducing a multiplexed stream in which a plurality of types of data streams are multiplexed,
Connection means for connecting to a communication path for mutual communication with an external device;
Multiplexed stream acquisition means for acquiring the multiplexed stream;
One or more decoding means for decoding a particular type of the data stream;
Decoding possibility determination means for determining whether the decoding means can decode the data stream included in the multiplexed stream acquired by the multiplexed stream acquisition means;
When there is the data stream that is determined by the decoding possibility determination unit to be undecognizable by the decoding unit, the external apparatus can perform decoding processing from the external apparatus connected to the communication path. External device specifying means for specifying an external device capable of decoding the data stream by obtaining information indicating the type of the data stream through the connection means;
Transmitting means for transmitting the data stream that cannot be decoded by the decoding means to the external device specified by the external device specifying means;
Receiving means for receiving and storing decoded data generated by the external device decoding the data stream transmitted to the external device;
Reproduction unit information holding means for acquiring and holding the data amount of the minimum reproduction unit and the reproduction time of the minimum reproduction unit of the decoded data after each of the data streams multiplexed in the multiplexed stream is decoded When,
From the time when the receiving unit receives and stores the first data of the decoded data decoded by the external device to the time when the decoded data is received from the external device and stored for the data amount of the minimum reproduction unit. And the reproduction time of the minimum reproduction unit held by the reproduction unit information holding means, and when the reproduction time of the minimum reproduction unit is smaller than the time width, the data by the external device Transfer time determination means for controlling to stop the decoding process of the stream;
Delays the time span from the time when the transmission means starts transmitting the data stream to the external device to the time when the decoded data is received from the external device and stored by the amount of data in the minimum reproduction unit. As the time, the output reference time of the decoded data decoded by the decoding means is corrected by the delay time, and the decoded data decoded by the decoding means is output according to the corrected reference time, while the reception With respect to the decoded data received from the external device by means, the output of the leading data of the decoded data received from the external device by the receiving means is matched with the output of the decoded data decoded by the decoding means, Thereafter, synchronous control means for controlling to output according to the playback time of the minimum playback unit,
A data stream playback device is provided.

In order to achieve the above object, according to the present invention, there is provided a data stream decoding device that performs a decoding process on a data stream multiplexed in a multiplexed stream,
Connection means for connecting to a communication path for mutual communication with an external device;
One or more decoding means for decoding a particular type of the data stream;
Type information indicating the type of data stream that can be decoded by the one or more decoding means, status information indicating whether or not the one or more decoding means are currently in use, and identification information of the data stream decoding apparatus Information disclosing means for disclosing to the external device through the connecting means decoder ownership information including :
Receiving means for receiving the data stream transmitted from the external device through the connecting means based on the decoder ownership information ;
Decoding control means for decoding the data stream received by the receiving means using the decoding means corresponding to the type of the data stream;
Transmitting means for transmitting the decoded data generated by decoding the data stream by the decoding means to the external device by the decoding control means;
A data stream decoding apparatus is provided.

  The present invention has the above-described configuration, and even when a data stream that cannot be decoded by the playback device is multiplexed in the multiplexed stream that is played back by the playback device, the data stream is decoded. Has the effect of making possible. Further, particularly when viewed from the user, it is felt that the decoding process for all the data streams is performed in one data stream reproducing apparatus, and the synchronous reproduction of the data streams that does not give the user a sense of incongruity is realized. It has the effect.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a system configuration in the embodiment of the present invention. In the system configuration shown in FIG. 1, a playback device (data stream playback device) 100a, an external device (data stream decoding device) 100b, and a server 100c are connected to a network 400. Note that the term “external” is used to indicate that the external device 100b connected to the network 400 is a different device for the playback device 100a. The network 400 is an arbitrary network, and may be, for example, a user's home network (home network) or a global network such as the Internet.

  Next, the internal configurations of the playback device 100a, the external device 100b, and the server 100c shown in FIG. 1 will be described.

  FIG. 2 shows an example of the internal configuration of the playback apparatus according to the embodiment of the present invention. 2 includes a recording medium reading unit 102, a command unit 103, a DEMUX unit 104, buffers A 105, 106, and 122, decoders 107 and 108, buffers B 109, 110, and 125, an STC (System Time Clock). ) Output unit 111, external connection information memory 120, decoder ownership information memory 121, external output buffer detector 123, external input buffer detector 124, delay time memory 127, and external input / output interface 131.

  The recording medium reading unit 102 reads a multiplexed stream obtained by multiplexing a plurality of data streams recorded on the recording medium 101 based on a reproduction command from the command unit 103, and the read multiplexed stream is a DEMUX unit. The function of supplying to the terminal 104 is provided.

  The command unit 103 has a function of issuing a playback command for the recording medium 101 based on a predetermined trigger such as activation by a timer or a playback instruction by a user operation, and supplying the playback command to the recording medium reading unit 102.

  Further, the DEMUX unit 104 separates (DEMUX) each type of multiplexed stream in which a data stream specialized for one or more types of video and audio is multiplexed, and then performs PMT (Program Map) of the data stream described later. (Table: program map table) and decoder possession information, and has a function of discriminating between a data stream that can be decoded by the playback apparatus 100a and a data stream that cannot be decoded. Each decodable data stream is distributed and stored in the buffers A 105 and 106, while the undecodable data stream is stored in the buffer A 122.

  Further, when a packet including a PCR (Program Clock Reference) is input as a data stream, the packet is supplied to the STC output unit 111 and time adjustment based on information in the PCR is performed.

  Further, the buffers A 105 and 106 have a function of storing a decodable data stream separated by the DEMUX unit 104. Each type of data stream stored in the buffers A 105 and 106 is then transferred to the decoders 107 and 108. The buffer A 122 has a function of storing the undecodable data stream separated by the DEMUX unit 104. The data stream stored in the buffer A 122 is then transferred to the decodable external device 100b through the external input / output interface based on external connection information (described later) stored in the external connection information memory 120.

  The decoders 107 and 108 correspond to the buffers A 105 and 106 and the buffers B 109 and 110, respectively. The decoders 107 and 108 perform decoding processing on the data streams stored in the buffers A 105 and 106, respectively. 110 has a function of storing a decoded data stream (decoded data).

  The buffers B109 and 110 have a function of storing the decoded data decoded by the decoders 107 and 108, respectively. The decoded data stored in the buffers B 109 and 110 are then output to the outside through an output device 140 (image output display, audio output speaker, etc.). In the present invention, the output of the decoded data (decoded data) from the buffers B109 and 110 may be temporarily delayed in consideration of the delay time T2, so that the buffers B109 and 110 take this delay into account. It is necessary to have a buffer size that does not cause overflow.

  Note that the buffer A 105, the decoder 107, the buffer B 109, the buffer A 106, the decoder 108, and the buffer B 110 are defined as one set of decoders corresponding to one compression format. Here, the playback apparatus 100a includes the two decoders 107 and 108, but may include more decoders and buffers associated with the decoders.

  Further, the STC output unit 111 has a timekeeping function that records a reference time (STC: System Time Clock) inside the playback apparatus 100a. For example, when the PCR (Program Clock Reference) included in the multiplexed stream is supplied, the STC can adjust the reference time based on the information in the PCR. It is.

  The external connection information memory 120 basically holds identification information (for example, an IP address) that can identify the external device 100b, and can be decoded by the external device 100b in association with the identification information. A function of storing information on the compression format of a data stream (information specifying the compression format, PID, etc.) as external connection information.

  The decoder possession information memory 121 has a function of storing information on the decoders 107 and 108 (for example, information on a compression format that can be decoded by the decoders 107 and 108) provided in the playback apparatus 100a. . FIG. 7 shows an example of decoder ownership information stored in the decoder ownership information memory 122. As shown in FIG. 7, the decoder possession information is that the own playback device 100a (here, a device specified by MODEL AB-CD100, IP address: 10.0.0.3) has a stream_type of MPEG-2 Video and Dolby. It has two types of decoders, Digital AC-3, and holds the type, transfer format, and status of each decoder.

  For example, the server 100c on the network 400 capable of mutual communication with the playback device 100a owns the decoder ownership information, and the playback device 100a can acquire the decoder ownership information from the server 100c as necessary. May be. In this case, the server 100c can hold the decoder ownership information of all devices on the network 400 as all decoder ownership information as will be described later.

  The external output buffer detector 123 has a function of controlling the output of the data stream stored in the buffer A 122, and the time when the data stream starts to be transferred from the buffer 122 in the playback device 100a (time t1 described later). It has a function to output.

  The external input buffer detector 124 has an input control function for the data stream stored in the buffer B 125, and the decoded data corresponding to the access unit display in the decoded data obtained by the decoding process in the external device 100c is stored. It has a function of outputting the time (time t3 to be described later) stored in the buffer B125 in the playback device 100a.

  Further, the external input buffer detector 124 obtains the time (time t2 described later) when the decoded data is first input to the buffer B125, and transfers the decoded data for the access unit display from the external device 100c to the playback device 100a. Time (time width T1 = time t3−time t2) required for the calculation, and the access unit display information stored in the access unit display information memory 126 is compared with the time width T1, and the external device 100c It has a function of determining whether or not decoding processing is possible. When it is determined that the decoding process by the external device 100c is impossible, the external input buffer detector 124 may instruct to stop the decoding process or the data stream transfer process in the playback device 100a. Is possible.

  The access unit display information memory 126 has a function of storing access unit display information of each data stream recorded on the recording medium 101. The access unit display information is information representing the time width of the access unit (that is, the minimum reproduction unit) as shown in FIG.

  The delay time memory 127 has a function of storing and outputting a difference value (delay time width T2 = time t3−time t1) between the output value of the external output buffer detector 123 and the output value of the external input buffer detector. doing. A change time obtained by subtracting the delay time width T2 output from the delay time memory from the reference time output from the STC output unit 111 is supplied to the buffers A 109, 110, and 125, and is used as a reference when outputting decoded data. By using it as time, synchronous output from the buffers A 109, 110, and 125 is realized.

  Further, the external input / output interface 131 converts the data into a transmission format compatible with the network 400 and transmits the data stream to the network 400 (for example, the external device 100b on the network 400) and receives the data stream received from the network 400. It has a function of converting and storing it in the buffer A125. When the external input / output interface 131 receives external connection information, the external snow image information is stored in the external connection information memory 120.

  FIG. 3 shows an example of the internal configuration of the external device according to the embodiment of the present invention. The external device 100b illustrated in FIG. 3 includes a DEMUX unit 151, a buffer C152, a decoder 153, a buffer D154, an STC output unit 155, an external input / output interface 181, and a decoder ownership information memory 182.

  Similar to the DEMUX unit 104 of the playback apparatus 100a described above, the DEMUX unit 151 separates (DEMUX) the multiplexed stream in which one or more types of data streams specialized for video, audio, and the like are multiplexed (DEMUX). It has a function. When a packet including PCR is input to the data stream, the packet is supplied to the STC output unit 155, and time adjustment based on information in the PCR is performed.

  The buffer C152 has a function of storing a decodable data stream separated by the DEMUX unit 104. The decoder 153 has a function of performing a decoding process on the data stream stored in the corresponding buffer C152 and storing the decoded data stream (decoded data) in the corresponding buffer D154. The buffer D154 has a function of storing the decoded data decoded by the decoder 153. In this example, one buffer C152, decoder 153, and buffer D154 are set, but the external device 100b may have two or more decoders and buffers corresponding to the decoders.

  In addition, the STC output unit 155 has a timekeeping function that records a reference time (STC: System Time Clock) inside the external device 100b. For example, when the PCR (Program Clock Reference) included in the multiplexed stream is supplied, the STC can adjust the reference time based on the information in the PCR. It is.

  The external input / output interface 181 receives and converts the data stream received from the playback device 100a on the network 400, supplies the data stream to the DEMUX unit 151, and transmits the decoded data stored in the buffer D154 to the network 400. It has a function of converting the data stream into a format and transmitting it to the playback device 100a on the network 400.

  The decoder ownership information memory 182 is provided in the external device 100b in the same manner as the decoder ownership information memory 121 of the playback device 100a (that is, similar to the decoding ownership information shown in FIG. 7 described above). It has a function of storing information of the decoder 153 (for example, information of a compression format that can be decoded by the decoder 153).

  Note that the playback apparatus 100a obtains and refers to the decoder ownership information stored in the decoder ownership information memory 182 of the external apparatus 100b, so that the external apparatus capable of decoding a data stream that cannot be decoded by the playback apparatus 100a. Can be searched.

  FIG. 4 shows an example of the internal configuration of the server according to the embodiment of the present invention. The server 100c illustrated in FIG. 4 includes an external input / output interface 191 and an all decoder ownership information memory 192.

  The external input / output interface 191 is connected to the network 400 and receives information (for example, decoder ownership information of each device and all of all devices on the network 400) with devices on the network 400 (the playback device 100a and the external device 100b). (Decoder ownership information) is transmitted and received.

  The all-decoder ownership information memory 192 has a function of storing all-decoder ownership information of all the devices on the network 400 obtained by collecting the decoder-owning information of each device (the playback device 100a and the external device 100b). Yes. FIG. 8 shows an example of all decoder ownership information stored in the all decoder ownership information memory 192. As shown in FIG. 8, all decoder ownership information holds the device name and address of each device 100 connected to the network 400, each decodable stream_type, decoder type, transfer format, and status. doing.

  Note that the server 100c has a function of integratedly managing decoder ownership information on the system. For example, when the playback device 100a makes an inquiry about decode ownership information to all other external devices on the network 400, It is not always necessary to provide the server 100c.

  Next, an outline of the operation of the system shown in FIG. 1 (a system in which each component has an internal configuration shown in FIGS. 2 to 4) will be described with reference to FIG. FIG. 5 is a flowchart showing an example of the operation of the playback apparatus according to the embodiment of the present invention.

  When an instruction to start reproduction of a predetermined data stream recorded on the recording medium 101 (hereinafter sometimes simply referred to as a stream) is issued, and a reproduction instruction is issued from the instruction unit 103 to the recording medium reading unit 102 The recording medium reading unit 102 reads the reproduction target multiplexed stream recorded on the recording medium 101 and supplies the read multiplexed stream to the DEMUX unit 104.

  The DEMUX unit 104 performs a sorting process for determining whether or not the playback target multiplexed stream (playback multiplexed stream) includes a data stream that cannot be decoded by the playback apparatus 100a (step in FIG. 5). S1001).

  Here, the distribution process in step S1001 will be described. In the multiplexed stream, information indicating what kind of data stream is multiplexed may be multiplexed together with a plurality of types of data streams. For example, when the data stream has an MPEG-2 TS (Transport Stream) structure, the multiplexed stream is composed of an integer number of packets each having 188 bytes as a unit, and each packet includes: An identifier (PID: identifier called packet identifier) for identifying which data stream constitutes a packet is added with a different value for each data stream.

  In addition to the packets constituting the data stream, information called PMT (Program Map Table) is multiplexed as a packet in the multiplexed stream. In this PMT, PID (packet identifier) and stream_type (stream type identifier indicating the type of stream) of all data streams included in the multiplexed stream are described. The DEMUX unit 104 refers to the PMT and the PID of each packet in the multiplexed stream, and also refers to and confirms the decoder possession information stored in the decoder possession information memory 121 of the playback device 100a. A sorting process is performed to determine whether or not the data stream can be decoded in the playback device 100a.

  Further, PCR (Program Clock Reference) is multiplexed as a packet in the multiplexed stream. Note that PCR refers to the encoding processing start time (DTS: Decoding Time Stamp) of each display access unit (for example, the minimum display / playback unit corresponding to a picture or audio frame in MPEG Video), and decoding after decoding. Reference time information of data display start time (PTS: Presentation Time Stamp). The PID of the packet including the PCR is also described in the PMT. When the packet including the PCR is input to the DEMUX unit 104, the PCR is input to the STC output unit 111 that records the reference time in the playback device 100a. Is transferred and the time is adjusted.

  FIG. 6 shows an example of the structure of the PMT described above. As shown in FIG. 6, the PMT holds the correspondence between PID and stream_type. In FIG. 3, the packet with PID = 0x1001 is PCR, the packet with PID = 0x1011 is MPEG-2 Video, the packet with PID = 0x1021 is Dolby Digital AC-3, the packet with PID = 0x10A1 is MPEG-1 Audio Layer 3, and PID = In the packet of 0x1101, the relationship of Text Subtitle (caption) is defined by PMT.

  The DEMUX unit 104 compares the information typified by the above-described PMT (decoder information in another device) with the decoder possession information (decoder information in the own playback device 100a), and performs a decoding process in the playback device 100a. It is possible to execute the sorting process in step S1001 by discriminating between the data stream that can be recorded and the data stream that cannot be decoded in the playback device 100a.

  As another method, instead of information existing in a multiplexed stream such as PMT, attribute information having the same information as PMT is recorded in the recording medium 101 in a different area from the multiplexed stream. It is also possible to perform the sorting process by reading the attribute information in advance before starting the multiplexed stream reading process and comparing the decoded possession information with the attribute information. In this case, before the multiplexed stream is read from the recording medium 101, it is possible to execute a sorting process for determining whether or not the data stream can be decoded in the self-playing device 100a.

  As a result of the discrimination by the sorting process, the data stream packets that can be decoded by the playback device 100a are sorted and stored for each PID in the buffers A105 and 106. On the other hand, a packet of a data stream that is determined to be impossible to decode by the playback device 100a is stored in the buffer A122.

  If there is a data stream that is determined not to be decrypted by the playback device 100a, a device (external device) on the network 400 that can decrypt the data stream is searched. Here, a description will be given of a method of finding an external device that exists on the network 400 capable of mutual communication with the playback device 100a and that can perform the decoding process of the data stream that is determined to be impossible to decode within the playback device 100a. To do.

  When the external device 100b existing on the network 400 stores its own decoder ownership information in the decoder ownership information memory 182, the playback device 100a is stored in the decoder ownership information memory 182 of the external device 100b. Whether or not the external apparatus 100b can decode the data stream that is determined to be unrecognizable by the reproducing apparatus 100a by acquiring the decoder owned information (step S1002 in FIG. 5) and referring to the decoder owned information. Is confirmed (step S1003 in FIG. 5).

  For example, when a specific device on the network 400 such as the server 100c holds the decoder ownership information of all the devices on the network 400 as the all decoder ownership information, the playback device 100a transmits all the decoders from the server 100c. By acquiring the ownership information and referring to the all-decoder ownership information, it is possible to search for the external device 100b capable of decoding the data stream that is determined to be impossible to decode by the playback device 100a.

  When an external device 100b that can decode a data stream that cannot be decoded by the playback device 100a is found by a search process of the external device 100b that can perform the decoding process, the playback device 100a connects to the external device 100b. External connection information (for example, unique information capable of identifying a device such as an IP address and information associated with the data stream (stream_type, PID, etc.)) stored in the external connection information memory 120 At the same time, a procedure for using the target decoder in the external device 100b is performed, and the data stream to be transferred to the external device 100b is stored in the buffer 122 (step S1004 in FIG. 5). Thereafter, the transfer of the data stream stored in the buffer 122 to the external device is started (step S1005 in FIG. 5).

  FIG. 9 shows an example of the external connection information described above. As shown in FIG. 9, in the external connection information, the name of the external device (external device name) is associated with the IP address of the external device, and the transfer stream_type, target PID, and transfer format of each external device. , The state is retained.

  Note that the above-described search process for searching for an external device capable of decoding a data stream is not necessarily performed when attribute information having the same information as that of the PMT is recorded in an area different from the multiplexed stream, for example. For example, it is possible to read the attribute information from the recording medium 101 immediately after the recording medium 101 is inserted into the reproducing apparatus 100a and search in advance.

  In addition, by using a non-volatile memory or the like as the external connection information memory 120 of the playback device 100a and storing the external connection information in this portable storage medium, search processing is performed when the recording medium 101 is played back in the future. This can be done quickly, improving convenience.

  Data streams that can be decoded by the playback device 100a stored in the buffers A 105 and 106 for each PID are decoded by the decoders 107 and 108 and stored in the buffers B 109 and 110, respectively. Are sorted and stored. On the other hand, a data stream that cannot be decrypted by the playback device 100a whose decoding processing is stored in the buffer A 122b by the playback device 100a is converted into a data type suitable for transfer in the network 400 by the external input / output interface 131, and then externally connected. The information is transferred to the external device 100b according to the information stored in the information memory 120.

  At this time, the external connection information stored in the external connection information memory 120 is processed in the same format as the multiplexed stream so that the external device 100b performs processing (that is, decoding processing) substantially the same as that of the playback device 100a. It may be necessary to transfer the data stream. For example, in the case of MPEG-2 TS, it is assumed that the decoding process cannot be performed by the external device 100b unless the multiplexed stream in which PMT and PCR are multiplexed is transferred to the external device 100b. Is done. As described above, it is desirable that the stream format in which each external device 100b is desired to be transferred can be determined by the decoder-owned information field external connection information.

 For example, when transfer in the MPEG-2 TS format is desired as described above, it is desirable to copy necessary packets such as PMT and PCR in the multiplexed stream by the DEMUX unit 104 and transfer them to the buffer 122. .

  Thereafter, the data stream transferred to the external device 100b is received by the external input / output interface 181 in the external device 100b, and then converted from a data type suitable for transfer on the network 400 to an actual data stream format. The The data stream is input to the DEMUX unit 151, is decoded by the decoder 153 via the buffer C152, and the decoded data obtained as a result is stored in the buffer D154.

  The decoded data stored in the buffer D154 is converted into a data type suitable for transfer in the network 400 at the external input interface 181 of the external device 100b, and the external input / output interface 131 of the playback device 100a is transmitted via the network 400. Forwarded to

  The decoded data transferred from the external device 10b to the external input / output interface 131 of the playback device 100a is converted from the data type suitable for transfer in the network 400 to the actual decoded data, and the decoded data received from the external device 100b. Are stored in the buffer B125.

  Note that the decoded data stored in the buffers B109, 110, and 125 may be supplied to the output device 140 as they are and output to the outside. However, the decoded data stored in the buffer B125 after being decoded by the external device 100b is automatically determined. There is a high possibility that a delay has occurred compared to when the playback apparatus 100a performs the decoding process.

  Therefore, the delay time in the transfer of the data stream in the network 400 between the playback device 100a and the external device 100b needs to be within a certain time. For this purpose, the network 400 satisfies the minimum data transfer rate. Confirmation processing is necessary to confirm this.

  Below, an example of the operation | movement of the confirmation process is demonstrated. First, the data stream determined to be transferred to the external device 100 b by the distribution process is first stored in the buffer 122. Thereafter, the data is transferred from the buffer 122 to the external input / output interface 131. The external output buffer detector 123 stores the time when the transfer from the buffer 122 to the external input / output interface 131 is started (transfer start time t1). . Thereafter, the data stream is converted into a data type suitable for transfer in the network 400 by the external input / output interface 131 and transferred to the external input / output interface 181 of the external device 100b.

  At the same time, the playback device 100a acquires the access unit display information of each data stream read from the recording medium 101 and stored in the access unit display information memory 126 before starting the playback of the multiplexed stream. .

  For example, in the case of an MPEG-2 Video stream, the access unit display information indicates the display time for one frame and the data amount for one frame (I, P, B frame) after decoding the video stream. It is. In the case of a resolution of 640 × 480 and a color depth of 24 bits, the display time for one frame is about 1/30 second, and the maximum amount of decoded data for one frame is about 1 MB. However, these values differ depending on the type and attribute of the data stream.

  FIG. 10 shows an example of the access unit display information described above. As shown in FIG. 10, the access unit display information is information indicating the time width of each access unit, its decoded data amount, etc., in addition to the correspondence information between the PID and its stream_type.

  The data stream transferred to the external device 100b is decoded in the external device 100b, and the decoded data obtained as a result is transferred to the playback device 100a and stored in the buffer B125. The external input buffer detection unit 124 stores, in the buffer B125, the time t2 when the decoded data is first input to the buffer B125, and then the data amount acquired by the access unit display information for the data stream transferred to the external device 100b. The time t3 is stored.

  When the external input buffer detection unit 124 obtains the times t2 and t3, the time interval T1 = t3−t2 from when the decoded data is first stored in the buffer B125 until the data amount corresponding to the access unit is stored. Calculation is made (step S1006 in FIG. 5). The time width T1 is a time necessary for transferring the decoded data for the access unit display from the external device 100b to the playback device 100a. A confirmation process for confirming whether or not the minimum data transfer rate is satisfied is performed using the time width T1 (step S1007 in FIG. 5).

  If the access unit display time width for the data stream stored in the access unit display information is smaller than the time width T1 (that is, the time width T1 that is the transfer time of decoded data for one access unit display is large). When the external device 100b performs the decoding process on the data stream instead of the playback device 100a, it means that the data stream is not displayed within the necessary time (that is, the display is not in time). In this case, since there is no guarantee that the decoded data of the data stream can be displayed at the necessary timing, the playback device 100a determines that the decoding process using the external device 100b is impossible for the data stream. Is desirable.

  Note that details of the above-described confirmation process for confirming that the network 400 satisfies the minimum data transfer rate will be described later with reference to FIG.

  In addition, since data streams and decoded data are transferred via the network 400, the external input / output interfaces 131 and 181 perform conversion processing to a data type suitable for the network 400, transfer on the network 400, and the playback device 100a. Similarly, due to a delay caused by performing decoding processing according to the STC in the external device 100b, the decoded data stored in the buffers B109 and 110 of the reproducing device 100a is stored in the buffer B125 at the time to be output. There is a possibility that the decoded data to be output synchronously is not stored. Therefore, it is necessary to output the decoded data stored in the buffers B109 and 110 in consideration of the delay time.

  The delay time width T2 can be obtained from a difference value obtained by subtracting the transfer start time t1 from the time t3. That is, the delay time width T2 indicates that the decoded data corresponding to the access unit display of the decoded data obtained by the decoding process in the external device 100b from the transfer start time t1 when the transfer of the data stream from the buffer A122 of the reproducing device 100a is started. This is the time width up to time t3 stored in the buffer B125 of the playback device 100a. The delay time width T2 is stored in the delay time memory 127 after calculation.

  The delay time width T2 is a time indicating how much a delay occurs in the data stream when the external device 100b performs the decoding process as compared to the case where the data stream decoding process is performed in the playback device 100a. . This delay time width T2 is the difference between the decoded data decoded by the decoders 107 and 108 of the playback device 100a and stored in the buffers B105 and 106, and the decoded data decoded by the external device 100b and stored in the buffer B125. Used to correct and realize synchronous output.

  For example, in the case of an MPEG-2 Video stream, as described above, time information called DTS and PTS is stored in the MPEG-2 Video data stream for each picture. For example, in the configuration of FIG. 2, the time when output of certain picture data from the buffer A 105 is started is DTS, and the time when decoded data (decoded data) of a certain picture is output from the buffer B 109 is PTS. Then, the STC output unit 111 performs time adjustment of the STC by acquiring reference time information called PCR that exists in the multiplexed stream, and the playback device 100a performs each behavior based on PTS and DTS ( It is possible to recognize the start time of decoding processing and output display.

  In the present invention, the delay time T2 stored in the delay time memory 127 is subtracted from the time indicated by the STC output unit 111 having a reference time for performing the decoding process and the output of the decoded data only within the playback apparatus 100a. The changed time is handled as the reference time in the output control from the playback device 100a.

  Based on the corrected reference time, the decoded data decoded by the player 100a is output from the buffers B109 and 110, and the decoded data decoded by the external device 100b is output from the buffer B125. Thus, synchronous output is performed (step S1200 in FIG. 5).

  That is, the data in the buffers B109 and 110 that are originally output in synchronization with the time indicated by the STC output unit 111 are output in synchronization with the change time, while the first output time of the data in the buffer B125 is the buffer B109. , 110 is synchronized with the time when the decoded data is first output, and thereafter, the amount of data for the access unit display is output for each display time of the access unit described in the access unit display information. It is possible to output the data decrypted in step 1 and the data decrypted in the external device 100b in synchronization.

  However, the delay time T2 may fluctuate every time the decoded data of the access unit is acquired from the external device 100b depending on the state of the network 400. Therefore, if the time width stored in the delay time memory 127 is changed each time, the time width at which the decoded data of the access unit is started to be output from the buffers B 109, 110, and 125 to the output device 140 also fluctuates. May be incurred.

  In order to avoid the problem, for example, a value obtained by adding the margin time width to the delay time width for the access unit acquired from the external device 100b immediately after the start of reproduction is set in the delay time memory 127, and thereafter, the access unit from the external device 100b. When the delay time calculated every time the decoded data is acquired is smaller than the time stored in the delay time memory 127, the value stored in the delay time memory 127 is not changed.

  As a result, it is possible to prevent deterioration in reproduction output quality without being affected by a minute variation in the delay time width for each access unit acquired from the external device 100b.

  Note that the margin time width needs to be calculated in consideration of conditions such as the maximum capacity of the buffers B 109, 110, and 125 in the playback device 100a.

  In addition to this example, a threshold level is provided for the value set in the delay time memory 127, and the value set in the delay time memory 127 is set as a threshold from the delay time T2 calculated every time the decoded data of the access unit is acquired from the external device 100b. A method of selecting and setting from the level is also considered effective.

  The details of the processing for obtaining the delay time width calculated for realizing the synchronized output of the decoded data by the own reproduction apparatus 100a and the decoded data by the external apparatus 100b will be described later with reference to FIG. .

  Also, if there is no stream that the playback apparatus 100a cannot decode in step S1001 in FIG. 5 (that is, all the data streams constituting the multiplexed stream can be decoded), the stream to the external apparatus 100b is sent. Stream transfer is not performed, and decoding data is output based on the reference time output by the STC output unit 111, as usual (step S1300 in FIG. 5).

  Further, when there is no decodable external device 100b for a specific stream in step S1003 of FIG. 5 or when a transfer rate necessary for communication with the decodable external device 100b cannot be secured, A stream that cannot be decoded is not transferred (stopped) to the external device 100b (step S1101 in FIG. 5), and when the non-decryptable stream is stored in the buffer 122, it is discarded (cleared). (Step S1102 in FIG. 5).

  Further, in this case, the processing is divided depending on the presence / absence of a stream to be decoded by an external device (step S1103 in FIG. 5). When there is a stream to be decoded by the external device, the decoded data decoded by the playback device 100a is output from the buffers B109 and 110 based on the reference time corrected using the delay time T2. The decoded data decoded by the external device 100b is output from the buffer B125, whereby synchronous output is performed (step S1200 in FIG. 5). On the other hand, when there is no stream to be decoded by the external device, the decoded data is output based on the reference time output from the STC output unit 111 as usual (step S1300 in FIG. 5).

  Next, details of a confirmation process for confirming that the minimum data transfer speed is satisfied in the network 400 will be described with reference to FIGS. 11 and 12A to 12C.

  First, the playback device 100a obtains the data size and display time of one access unit (one display unit) after decoding the data stream to be transferred to the external device 100b based on, for example, a multiplexed stream or information from the outside (FIG. 11). Step S2001).

  Then, the playback device 100a stores the transfer start time t2 at the same time as the storage of the decoded data from the external device 100b is started in the buffer B125 in the playback device 100a (step S2002 in FIG. 11). As shown in FIG. 12A, the data transfer state at this time is such that the data stored in the buffer A122 (indicated by hatching in the figure) starts to be stored in the buffer B125 via the external device 100b. It becomes a state.

  The playback device 100a continues to store the decoded data from the external device 100b in the buffer B125 in the playback device 100a, and acquires the time t3 when the input for the data size of one access unit (one display unit) is completed ( Step S2003 in FIG. 11). The data transfer state at this time is such that the data stored in the buffer B125 increases as shown in FIG. 12B, and the data necessary for one display unit in the buffer B125 as shown in FIG. 12C. The amount of data is stored.

  Then, the playback device 100a calculates the difference time width T1 = time t3−time t2, and checks whether or not the difference time width is equal to or smaller than the display time width of one access unit (time width of one display unit) ( Step S2004 in FIG. 11).

  When the difference time width is equal to or less than the time width of one display unit, it is determined that the necessary transfer rate is satisfied (step S2005 in FIG. 11), and the difference time width is larger than the time width of one display unit. Is determined that the required transfer rate is not satisfied (step S2006 in FIG. 11).

  Next, referring to FIG. 13 and FIG. 14A to FIG. 14C, the processing for acquiring the delay time width calculated to realize the synchronous output of the decoded data by the own reproduction device 100a and the decoded data by the external device 100b. Details will be described.

  First, the playback device 100a acquires the data size and display time for one display unit (one access unit) after decoding the data stream to be transferred to the external device 100b from the access unit display information memory 126 (step S3001 in FIG. 13). ).

  Then, the playback device 100a starts the transfer of the data stream from the buffer A122 in the playback device 100a to the external device 100b, and simultaneously stores the transfer start time t1 (step S3002 in FIG. 13). Note that the data transfer state at this time is a state in which the data stored in the buffer A122 (indicated by hatching in the figure) starts to be transmitted to the external device 100b as shown in FIG. 14A.

  The playback device 100a stores the decoded data, which is decoded by the external device 100b and transferred to the playback device 100a, in the buffer B125 in the playback device 100a, and inputs for the data size of one access unit (one display unit). The completed time t3 is acquired (step S3003 in FIG. 13). Note that the data transfer state at this time is such that data is stored in the buffer B125 as shown in FIG. 14B, and the amount of data required for one display unit in the buffer B125 as shown in FIG. 14C. Only the data is stored.

  Then, the reproducing device 100a calculates the difference time width T2 = time t3−time t1, and stores this difference time width T2 as a delay time in the delay time memory 127 (step S3004 in FIG. 13).

  In FIG. 1 to FIG. 4, functions of each device are schematically represented by function blocks. However, each of these functions can be realized by hardware and / or software (program).

  In the system configuration examples illustrated in FIGS. 1 to 4, an example is given in which there are two types of decoders provided in the playback device 100 a and one type of data stream to be transferred to the external device 100 b. However, there is no limitation on the number of types of decoders, the number of data streams transferred from the playback device 100a to the external device 100b, and the like.

  Therefore, in practice, a set of the buffer A 105, the decoder 107, and the buffer B 109, which is a data stream path that can be decoded by the playback device 100a, is prepared for the number of decoders included in the playback device 100a, and transferred to the external device 100b. When there are a plurality of data streams to be processed, it is desirable that a set of the buffer A 122 and the buffer B 125 is prepared in the playback device 100a by at least the number of data streams to be transferred to the external device 100b.

  However, when there are a plurality of data streams to be transferred to the external device 100b, it is necessary to perform a transfer rate confirmation process for the time width T1 for each data stream. Regarding the delay time T2 to be stored in the delay time memory 127), the delay time is calculated for each data stream, and the one having the largest delay among them may be set in the delay time memory 127 as the delay time T2. desirable.

  The external device 100b may have a system configuration similar to that of the playback device 100a. That is, it is conceivable that the external device 100b is also a recording medium playback device that actively reads the recording medium 101, like the playback device 100a. For example, a playback command is issued to the external apparatus 100b by the user, and the multiplexed stream read from the recording medium 101 in the external apparatus 100b is currently transferred from the playback apparatus 100a, and decoding processing is performed. In some cases, a data stream of the same type as the data stream being included is included. In this case, it is desirable that the decoding process for the playback apparatus 100a is stopped and the decoding process for the data stream read from the recording medium 1010 is performed in the external apparatus 100b.

  As described above, when it is desired to stop the decoding process of the data stream transferred from the playback apparatus 100a to the external apparatus 100b for some reason, the external apparatus 100b first stops the decoding process and stops the decoding process. It is possible to notify the playback device 100a of a message that makes it possible to identify the type of the target data stream. When the playback apparatus 100a refers to the decode ownership information of the external apparatus 100b that is always transferring and checks the decoder usage status, the external apparatus 100b is using the status information related to the decoder for the data stream to be stopped. By changing to a state of not being used, the playback device 100a can refer to this information to delete information on the stop target data stream stored in the external connection information memory 120, and stop the transfer of the stop target data stream. It becomes like this.

  The present invention has the above-described configuration, and even when a data stream that cannot be decoded by the playback device is multiplexed in the multiplexed stream that is played back by the playback device, the data stream is decoded. And can be applied to a data stream decoding technique and a data stream reproduction technique for decoding and reproducing a broadcast or recorded data stream.

It is a figure which shows an example of the system configuration | structure in embodiment of this invention. It is a figure which shows an example of an internal structure of the data stream reproducing | regenerating apparatus in embodiment of this invention. It is a figure which shows an example of the internal structure of the external device in embodiment of this invention. It is a figure which shows an example of the internal structure of the server in embodiment of this invention. It is a flowchart which shows an example of operation | movement of the reproducing | regenerating apparatus in embodiment of this invention. It is a figure which shows an example of the structure of PMT used with the data stream reproducing | regenerating apparatus in embodiment of this invention. It is a figure which shows an example of the decoder ownership information stored in the decoder ownership information memory of the data stream reproducing | regenerating apparatus in embodiment of this invention. It is a figure which shows an example of the all decoder ownership information stored in the all decoder ownership information memory of the server in embodiment of this invention. It is a figure which shows an example of the external connection information used with the data stream reproducing | regenerating apparatus in embodiment of this invention. It is a figure which shows an example of the access unit display information used with the data stream reproducing | regenerating apparatus in embodiment of this invention. 7 is a flowchart illustrating an example of a confirmation process for confirming a data stream transfer rate in the data stream reproduction device according to the embodiment of the present invention. FIG. 12 is a diagram illustrating a first example of a data transfer state in the confirmation process illustrated in FIG. 11. It is a figure which shows the 2nd example of the data transfer state in the confirmation process shown in FIG. FIG. 12 is a diagram illustrating a third example of a data transfer state in the confirmation process illustrated in FIG. 11. FIG. 7 is a flowchart showing an example of processing for obtaining a delay time width calculated in order to realize synchronized output of decoded data from the own reproducing device and decoded data from an external device in the data stream reproducing device according to the embodiment of the present invention. is there. FIG. 14 is a diagram illustrating a first example of a data transfer state in the delay time width acquisition process illustrated in FIG. 13. FIG. 14 is a diagram illustrating a second example of a data transfer state in the delay time width acquisition process illustrated in FIG. 13. FIG. 14 is a diagram illustrating a third example of a data transfer state in the delay time width acquisition process illustrated in FIG. 13.

Explanation of symbols

100a Playback device (data stream playback device)
100b External device (data stream decoding device)
100c server 101 recording medium 102 recording medium reading unit 103 command unit 104, 151 DEMUX unit 105, 106, 122 buffer A
107, 108, 153 Decoder 109, 110, 125 Buffer B
111, 155 STC output unit 120 External connection information memory 121, 182 Decoder possession information memory 123 External output buffer detector 124 External input buffer detector 126 Access unit display information memory 127 Delay time memory 131, 181, 191 External input / output interface 140 Output device 152 Buffer C
154 Buffer D
192 All decoder owned information memory 400 network

Claims (1)

A data stream reproduction device for reproducing a multiplexed stream in which a plurality of types of data streams are multiplexed,
Connection means for connecting to a communication path for mutual communication with an external device;
Multiplexed stream acquisition means for acquiring the multiplexed stream;
One or more decoding means for decoding a particular type of the data stream;
Decoding possibility determination means for determining whether the decoding means can decode the data stream included in the multiplexed stream acquired by the multiplexed stream acquisition means;
When there is the data stream that is determined by the decoding possibility determination unit to be undecognizable by the decoding unit, the external apparatus can perform decoding processing from the external apparatus connected to the communication path. External device specifying means for specifying an external device capable of decoding the data stream by obtaining information indicating the type of the data stream through the connection means;
Transmitting means for transmitting the data stream that cannot be decoded by the decoding means to the external device specified by the external device specifying means;
Receiving means for receiving and storing decoded data generated by the external device decoding the data stream transmitted to the external device;
Reproduction unit information holding means for acquiring and holding the data amount of the minimum reproduction unit and the reproduction time of the minimum reproduction unit of the decoded data after each of the data streams multiplexed in the multiplexed stream is decoded When,
From the time when the receiving unit receives and stores the first data of the decoded data decoded by the external device to the time when the decoded data is received from the external device and stored for the data amount of the minimum reproduction unit. And the reproduction time of the minimum reproduction unit held by the reproduction unit information holding means, and when the reproduction time of the minimum reproduction unit is smaller than the time width, the data by the external device Transfer time determination means for controlling to stop the decoding process of the stream;
Delays the time span from the time when the transmission means starts transmitting the data stream to the external device to the time when the decoded data is received from the external device and stored by the amount of data in the minimum reproduction unit. As the time, the output reference time of the decoded data decoded by the decoding means is corrected by the delay time, and the decoded data decoded by the decoding means is output according to the corrected reference time, while the reception With respect to the decoded data received from the external device by means, the output of the leading data of the decoded data received from the external device by the receiving means is matched with the output of the decoded data decoded by the decoding means, Thereafter, synchronous control means for controlling to output according to the playback time of the minimum playback unit,
A data stream reproducing apparatus having

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