JPH1023399A - Mpeg2 data regenerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MPEG2 regenerating device capable of regenating data by analyzing the stream format of MPEG2 data by the device itself before regenerating to automatically set a proper reproduction mode. SOLUTION: An analyzing means 13 judges whether or not the synchronizing byte of a transport stream is present in stream data received by a receiving means 11, and communicates the presence of a transport stream mode to the central control means 17 when the synchronizing byte is present, and communicates the presence of a program stream mode when the synchronizing byte is not present. At the time of receiving the communication of the transport steam mode from the analyzing means 13, the central control means 17 instructs a separation method corresponding to the transport stream to a system decoder 15, and at the time of receiving the communication of the program stream mode, the central control means 17 instructs a separation method corresponding to the program stream.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to MPEG2 (Mov).
ing Picture Image Coding Experts GroupPhase
2) MP that receives data (MPEG2 data) encoded according to the standard and reproduces the MPEG2 data
The present invention relates to an EG2 data reproducing device.

[0002]

2. Description of the Related Art
An apparatus that reproduces data encoded according to the MPEG2 standard is designed to reproduce only one of the two stream formats defined by the MPEG2 standard, the transport stream (TS) format and the program stream (PS) format. Some of them are set in advance, whether they correspond to the transport stream format or the program stream format, and after setting, there are some that can only reproduce data in the corresponding format. I was

A device for reproducing data in a transport stream format includes a set top box (STB) which is a terminal in a digital CATV system, a digital satellite communication system, and the like. On the other hand, as an example of reproducing data in a program stream format, there is a case where data in a program format is read from a storage medium such as a DVD digital video disc and reproduced. As described above, it is good if the format of the playback device is greatly different for each data format, but if multimedia becomes more advanced in the future, an integrated device that can reproduce various data with one playback device is desired. Will be done.

In such a case, the MP used by the user
If it is necessary to change the reproduction mode of the apparatus to a corresponding one while taking the stream format of the EG2 data into consideration, the user is forced to perform a very troublesome operation, which is not preferable. Accordingly, the present invention has been made in view of the above-described problems, so that the apparatus itself analyzes the stream format of MPEG2 data before playback, and automatically sets an appropriate playback mode corresponding to the stream format so that data playback can be performed. Accordingly, it is an object of the present invention to provide a user-uninterrupted MPEG2 playback device with improved convenience.

[0005]

Means for Solving the Problems and Effects of the Invention MPEG2 according to claim 1 has been made to achieve the above object.
The data reproducing apparatus includes a receiving unit that receives data (MPEG2 data) encoded according to the MPEG2 standard in a stream state, and a separating unit that separates at least audio and video PES packets from the received stream state MPEG2 data. An audio information reproducing unit for reading time management information from the audio PES packet separated by the separating unit and, when a predetermined time to be reproduced comes, reproducing the audio information of the corresponding PES packet into an audio signal; Video information reproducing means for reading time management information from the video PES packet separated by the separating means and, when a predetermined time to be reproduced comes, reproducing the video information of the corresponding PES packet into a video signal; Received by an MPEG2 data reproducing device equipped with Analysis means for analyzing the stream format of the MPEG2 data in a stream state received via the stage; separation method control means for controlling the separation method in the separation means to correspond to the stream format analyzed by the analysis means; It is characterized by having.

According to the MPEG2 data reproducing apparatus of the present invention, data encoded according to the MPEG2 standard (MPEG2
Data) in a stream state, and separates the received MPEG2 data in the stream state into at least audio and video PES packets. And
The time management information is read from the separated audio PES packet, and when a predetermined time to be reproduced comes, the audio information of the corresponding PES packet is reproduced as an audio signal, and the time is read from the separated video PES packet. When the management information is read and a predetermined time to be reproduced comes, the video information of the corresponding PES packet can be reproduced as a video signal.

[0007] Although such a basic function is provided, even if the stream format of the received MPEG2 data is not fixed, it can automatically cope with the stream format. Analyzes the stream format of the received MPEG2 data in the stream state,
The separation method control means controls the separation method in the separation means so as to correspond to the stream format analyzed by the analysis means.

Therefore, for example, when MPEG-2 data streamed in either a transport stream or a program stream is received, the separation method control means uses a separation method corresponding to any of the stream formats. To the separating means. For this reason, the separation means executes separation processing on the MPEG-2 data in the transport stream format by a separation method corresponding to the transport stream,
Separation processing is performed on MPEG2 data in the program stream format by a separation method corresponding to the program stream.

As described above, the apparatus itself analyzes the stream format of MPEG2 data before playback, and can automatically set the playback mode to an appropriate playback mode corresponding to the stream format, thereby enabling data playback. In other words, if it is necessary to change the playback mode of the apparatus to a corresponding mode while taking into consideration the stream format of the MPEG2 data used by the user, it is necessary to force the user to perform a very troublesome operation. However, such an inconvenience does not occur in the MPEG2 data reproducing apparatus of the present invention, the convenience is improved, and the apparatus can be made user-friendly.

As a device for reproducing data in a transport stream format, there is a set-top box (STB) which is a terminal in a digital CATV system, a digital satellite communication system or the like. On the other hand, as an example of reproducing data in a program stream format, there is a case where data in a program format is read from a storage medium such as a DVD digital video disc and reproduced. Since it is conceivable that these are expected to be integrated so that various data can be reproduced by one reproducing apparatus as multimedia becomes more advanced in the future, the MPEG2 data reproducing method of the present invention is also considered. It is very effective to be able to automatically analyze the stream format and perform appropriate separation / reproduction like a device.

[0011] The analyzing means is an MP in a stream state.
It is sufficient if the stream format can be analyzed based on the data and the like included in the EG2 data. For example, from the MPEG2 data in the stream state, it is determined whether or not there is a synchronization byte set for each transport packet constituting the transport stream. It is conceivable to analyze the stream format on the basis of the stream format. This is because a transport packet constituting a transport stream has a fixed length of 188 bytes and a synchronization byte (8 bits) in its header.
This is because accurate determination can be made by taking into account the fact that the synchronization byte appears repeatedly every 188 bytes.

[0012]

Next, embodiments of the present invention will be described in detail. FIG. 1 is a block diagram showing a configuration of the MPEG2 data reproducing apparatus 10. MPEG2 data is input to the MPEG2 data reproducing apparatus 10 as data in a stream state, and the input data is received by the receiving means 11. The data received by the receiving means 11 is sent to the analyzing means 13.

The analyzing means 13 analyzes whether the data stream format is a transport stream (TS) or a program stream (PS), notifies the central control means 17 of the distinction between the TS and the PS, and separates the data from the separating means. Is also sent to the system decoder 15. The analysis process will be described later.

The central control means 17 is a control means for controlling the entire apparatus, and has a function as a separation method control means. In other words, based on the distinction between TS and PS notified from the analysis means 13, the instruction of the separation method is sent to the system decoder 15. Instructions for this separation method will also be described later.

The system decoder 15 separates and constructs the streamed reception data into an audio PES packet or a video PES packet based on an instruction of the separation method from the central control means 17, and the audio PES packet is an audio PES packet. The video PES packet is output to the buffer 21 and the video PES packet is output to the video buffer 31. That is, the system decoder 15 of the present embodiment
The separation method executed by the own device is a separation method compatible with TS and PS.
It is configured to be able to select and set two methods of the corresponding separation method, and which of the two methods is selected is determined based on an instruction from the central control means 17. Note that PES (P
acketized Elementary Stream) packet is MPE
MPEG2 is used when calling packets in G2.
-Shared by PS and MPEG2-TS.

An audio decoder 23 corresponding to the audio information reproducing means can read out and decode the audio PES packet from the audio buffer 21 and output it to the amplifier 25 as an analog audio signal. The amplifier 25 can amplify the audio signal, send the amplified signal to the speaker 27, and output the sound.

A video decoder 33 corresponding to the video information reproducing means outputs a video PE from the video buffer 31.
The S packet can be read, decoded, and output as an analog video signal to the television monitor 35, and the reproduced video can be displayed on the television monitor 35.

This is the MPEG2 data reproducing apparatus 10
Of the MPEG2 data reproducing apparatus 10 according to the present invention.
There are two types of data to be input to the, such as data in a transport stream format and data in a program stream format. These will be described below.

First, the transport stream (TS) will be described with reference to FIG. FIG. 4 shows the data structure of the TS in a hierarchical manner. The TS is a stream multiplexed by fixed-length transport packets of 188 bytes. The transport packet is usually shorter than the PES packet, and is a packet obtained by dividing the PES packet into a transport packet, and includes a header portion and a payload as an execution data portion.

The header section includes an 8-bit synchronization byte, a 1-bit error indication, a unit start indication and a transport packet priority, and a 13-bit PID (Packet Identity) for identifying a packet.
ion), 2-bit scrambling control, 2-bit adaptation field control, 4-bit cyclic counter, and predetermined-bit adaptation field.

The adaptation field can optionally include additional information about the individual stream and 8 × M-bit stuffing bytes (invalid data bytes), thereby transmitting information on the dynamic state change of the individual stream. can do. It consists of an adaptation field length of 8 bits, discontinuous display of 1 bit each, random access display and stream priority display, conditional coding, and the like.
+6 bit PCR (Program Clock Reference: reference value of program time reference), 42 + 6 bit OPCR
(Original PCR).

Next, the program stream (PS) will be described with reference to FIG. FIG. 5 shows a hierarchical structure of the data structure of the PS. In the PS, a packet is placed after a pack header and a system header in the first pack, and the packet is placed immediately after the pack header in the next pack. And a 32-bit end code is added at the end.

The pack header has a pack start code of 32 bits, 2 bits of "10", and 42 + 4 bits of SC.
R (System Clock Reference: system time reference value), a multiplexing rate of 22 + 2 bits, a stuffing length of 3 + 5 bits, and a stuffing byte of 8 × M bits. On the other hand, the system header is
32-bit system header start code, 16-bit header length, 22 + 2-bit bit rate, 6-bit audio channels, 4 + 1-bit 4 flags, 5-bit video channels, 8-bit reserved bytes, It consists of 24 × N bits of N-loop basic stream information.

As described above, a pack header and a system header of several bytes to several tens of bytes are added to the first pack as a header part other than the packet, and thereafter a plurality of packets are added. Then, to the next pack, only the pack header is added as a header part other than the packet, and thereafter, a plurality of packets are added.

Next, the operation of the MPEG2 data reproducing apparatus 10 of the present embodiment will be described with reference to the flowcharts of FIGS. The flowchart of FIG. 2 shows an analysis process performed by the analysis unit 13.
First, in the first step S10, the stream data is analyzed to determine whether or not there is a synchronization byte in the TS header. This synchronization byte is represented by TS as shown by arrow A in FIG.
Present at the beginning of the packet header. As described above, the transport packet constituting the transport stream has a fixed length of 188 bytes, and the synchronization byte (8 bits) is included in the header portion thereof, so that the synchronization byte repeatedly appears every 188 bytes. . Therefore, the presence or absence of the synchronization byte can be accurately determined.

Based on the result of the determination of the presence or absence of the synchronization byte in S10, whether the stream format is TS or not is determined in S20.
Is determined. If the presence of the synchronization byte is confirmed, the stream format is TS, and the process proceeds to S30,
The central control means 17 is notified of the TS mode.
On the other hand, if the existence of the synchronization byte cannot be confirmed, the stream format is PS, and the flow shifts to S40 to notify the central control means 17 of the PS mode.

The flowchart of FIG.
7 shows a separation method control process executed in FIG.
First, in the first step S110, the analyzing means 13
Determine if there is more notification. This notification is a notification of the TS mode or the PS mode made by the processing of S30 or S40 in FIG. 2 described above.

In S120, it is determined whether the mode notified this time is different from the previous mode. If the mode is the same as the previous mode (S120: NO), there is no need to change the separation method this time, so this processing is once ended as it is. On the other hand, if the mode is different from the previous mode (S120: Y
ES), since the separation method needs to be changed this time,
The processing after 30 is executed.

In S130, it is determined whether the notified mode is the TS mode or the PS mode. If the notified mode is the TS mode, the process shifts to S140, where the system decoder 15 is changed to the separation method corresponding to the TS mode. And give instructions. On the other hand, if the mode is the PS mode, the process shifts to S150 to instruct the system decoder 15 to change to the separation method corresponding to the PS mode.

After the processing in S140 or S150 is completed, the flow shifts to S160 to instruct the system decoder 15 to start system decoding. As described above, in the system decoder 15 in which the TS-compatible separation method is instructed by the processing of S140, the audio PES packet or the video PE
The setting of the own device is changed so as to be a separation method capable of separating and constructing the S packet. On the other hand, the system decoder 15 to which the PS-compatible separation method has been instructed by the processing in S150 has its own apparatus so that the separation method can separate and construct an audio PES packet or a video PES packet from a program stream as shown in FIG. Change settings.

The audio PES packet and the video PES packet appropriately separated / constructed by each separation method are stored in the audio buffer 21 and the video buffer 31, respectively.
It is distributed to. Then, the audio buffer 21,
Audio PES allocated to video buffer 31
The packet and the video PES packet are read by the audio decoder 23 and the video decoder 33, respectively, and execute predetermined processing.

In the case of this embodiment, the audio P
It is separated into an ES packet and a video PES packet, and these are often expected to be synchronously reproduced. Regarding this synchronous reproduction, in the case of a transport stream, as indicated by an arrow B in FIG. 4, a PCR (Program Clock Re) in the header of each transport packet is used.
ference: program time reference value), while in the case of a program stream, the arrow C in FIG.
SCR included in the first pack header as shown by
(System Clock Reference: system time reference value) is used. These PCRs and SCRs are used as STCs (System Tim) of a synchronization signal serving as a time reference for decoding.
e Clock) is set to the intended value on the encoding side.
This is information for calibration. Therefore, if it is determined whether to use the PCR or the SCR related to the synchronization control depending on whether the stream is a transport stream or a program stream, appropriate synchronization control during reproduction can be performed.

As described above, the MPEG2 data reproducing apparatus 10 itself analyzes the stream format of the MPEG2 data before the reproduction, and can automatically set the reproduction mode to an appropriate reproduction mode corresponding to the stream format, thereby reproducing the data. In other words, if it is necessary to change the playback mode of the apparatus to a corresponding mode while taking into consideration the stream format of the MPEG2 data used by the user, it is necessary to force the user to perform a very troublesome operation. No, but this MPEG2
Such inconvenience does not occur in the data reproducing apparatus 10, the convenience is improved, and the apparatus can be user-unique.

As a device for reproducing data in the transport stream format, there is a set-top box (STB) which is a terminal in a digital CATV system, a digital satellite communication system, or the like. On the other hand, as an example of reproducing data in a program stream format, there is a case where data in a program format is read from a storage medium such as a DVD digital video disc and reproduced. It is conceivable that these are desired to be integrated so that various data can be reproduced by one reproducing apparatus as multimedia becomes more advanced in the future.
It is very effective to be able to automatically analyze the stream format like 0 and perform appropriate separation and reproduction.

Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. . For example, in the above-described embodiment, the stream data is analyzed to determine the presence or absence of a synchronization byte in the TS header.
If it is S, it is determined that it is PS if it is not, but another determination method may be used.

As the PES packet, in addition to the two types of audio and video described above, a private PES
Since there may be a packet, the packet may be separated. In that case, the system decoder 1
After 5, a private buffer and a private decoder may be provided.

Further, in the case of the above embodiment, the system decoder 15 uses the TS
It is configured to be able to select and set two methods, a corresponding separation method and a PS-compatible separation method, and which one to select is determined based on an instruction from the central control means 17, but for example, A TS system decoder preset for the TS-compatible separation method and a PS system decoder preset for the PS-compatible separation method are provided, and the central control means determines which of these system decoders is to be used. Alternatively, the determination may be made based on an instruction from 17.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an MPEG2 data reproducing apparatus according to an embodiment.

FIG. 2 is a flowchart illustrating an analysis process performed by an analysis unit.

FIG. 3 is a flowchart illustrating a separation method control process executed by a central control unit.

FIG. 4 is a data structure diagram of an MPEG2 transport stream.

FIG. 5 is a data structure diagram of an MPEG2 program stream.

[Description of Signs] 1 ... Receiving means 10 ... MPEG2 data reproducing device 11 ... Receiving means 13 ... Analyzing means 15 ... System decoder 17 ... Central control means 21 ... Audio buffer 23 ... Audio decoder 25 ... Amplifier 27 ... Speaker 31 ... Video buffer 33: Video decoder 35: TV monitor

Claims (3)

[Claims] 1. A receiving means for receiving data encoded according to the MPEG2 standard in a stream state, and from the received MPEG2 data in a stream state,
Separating means for separating at least audio and video PES packets; and reading time management information from the audio PES packets separated by the separating means. Audio information reproducing means for reproducing audio information into an audio signal; and time management information is read from the video PES packet separated by the separating means, and when a predetermined time to be reproduced comes, a corresponding PES packet is read. An MPEG2 data reproducing apparatus comprising: video information reproducing means for reproducing video information into a video signal; and a stream state MPE received via the receiving means.
Analysis means for analyzing the stream format of the G2 data; and separation method control means for controlling the separation method in the separation means to correspond to the stream format analyzed by the analysis means. MPEG2 data reproducing device. 2. The MPEG2 data in a stream state is streamed in a format of either a transport stream or a program stream, and the separating means corresponds to a separating method corresponding to the transport stream and a program stream. 2. The MPEG2 data reproducing apparatus according to claim 1, wherein the apparatus is configured to select and execute a separation method. 3. The method according to claim 1, wherein the analyzing means is a stream state MP.
3. The MPE according to claim 2, wherein the stream format is analyzed from EG2 data based on the presence / absence of a synchronization byte set for each transport packet constituting the transport stream.
G2 data playback device.