JPH1127154A - Coding/decoding method for image signal and audio signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for transmitting image and audio signals that discriminates automatically whether data are compressed or noncompressed data without a complicated configuration by adding information denoting whether data are compressed or noncompressed data to substantial data at a transmitter side, applying time division multiplex processing to the resulting data, transmitting the data as a transport stream(TS), detecting and discriminating the added information in the TS at a receiver side and decoding the data based on the result of the discrimination. SOLUTION: A TS generating section 3 generates a TS 9 resulting from multiplexing, e.g. video compression data and audio compression data or audio noncompression data and transmits the TS. In this case, a prescribed PID value is provided to the TS. A header analyzer 5-9 of a TS analysis section 5 retrieves the PID value in the received TS 10. Then a header analyzer 5-9 controls a demultiplexer 5-1 so that respective data are received by a prescribed memory based on the PID value being the result of retrieval and prescribed processing and decoding is conducted based on the PID value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for encoding and decoding moving picture signals and audio signals, and more particularly to an improvement in the use of header information in multiplexing and demultiplexing of moving picture signals and audio signals. It is.

[0002]

2. Description of the Related Art In recent years, image processing techniques, especially compression techniques for image information and audio information, have been remarkably developed, and high-quality moving images and audio can be transmitted even on a transmission line having a small capacity. became. By the way, in transmission of an audio signal in a broadcasting system, transmission during decoding and reproduction due to compression is disliked, and transmission of uncompressed data is required.
Therefore, a system that can transmit not only compressed data but also uncompressed data is required.

FIG. 2 shows a basic outline of a system for multiplexing and separating a moving picture and an audio signal. It comprises a camera, a microphone, a transport stream (hereinafter, referred to as TS) creating section 3, a transmitting section 4, a TS analyzing section 5, a monitor, and a speaker. When the TS creating unit 3 obtains a plurality of videos captured by a plurality of cameras, that is, a so-called video signal 1, the TS creating unit 3 compresses each of the video signals into compressed data. Similarly, when a plurality of audio signals 2 recorded by a plurality of microphones are obtained, the audio signals are compressed by an audio compression unit to obtain compressed data. The multiplexing unit adds information such as a header to each compressed data, and outputs the compressed data to the transmission unit 4 as a transport stream. The transmission unit 4 performs transmission by taking in the transport stream from the transmitting end and outputting the transport stream to the receiving end.
The TS analysis unit 5 transmits the transport stream to the transmission unit 4
, The multiplexed compressed data is separated and divided by the separation and division unit based on the header information in the transport stream. The video decompression unit and the audio decompression unit convert the compressed data separated and divided into decompressed data, and reproduce the decompressed data on a monitor and a speaker.

By the way, a method of separating and dividing arbitrary video and audio from a plurality of compressed video data and audio data in a transport stream is to search for a PID (Program ID) which is a part of header information. , And separates and divides the compressed data corresponding to the PID. This PID will be described with reference to FIG. FIG.
The outline of the transport stream created by the S creating unit 3 is shown. The transport stream is basically configured by repeating header information and compressed data.
In the example of FIG. 3, this transport stream is obtained by time-division multiplexing of compressed video data A, compressed audio data B, and compressed video data C in a predetermined unit time, and header information is added to each of them. The header information includes the P
There is header information called ID, which indicates the type of multiplexed compressed data, that is, so-called video data or audio data. A1 and A2 in the transport stream
Is a time-division multiplex of video compression data A, and P
ID1 and PID4 have the same PID value. Also, B1
And B2 are time-division multiplexed audio compressed data B, and PID2 and PID5 have the same PID value. Therefore, on the receiving side, A1 and A2 of the compressed video data A can be separated and divided by searching for the value of PID1, and similarly, B1 and B2 of the compressed video data B can be separated by searching for the value of PID2. It can be separated and divided.

Next, the details of this system will be described with reference to FIG. The TS creator 3 creates a VENC (Video E
ncoder) 3-1 and FIFO (First In First Out) memory 3
-2, AENC (Audio Encoder) 3-3, FIFO memory 3-4, STC (System Time Clock) counter 3-
5, latch 3-6, header information generator 3-7 ', system CK (clock) generator 3-8, header controller 3-
9 ', a multiplexing unit 3-10. VENC3
-1, FIFO memory 3-2, AENC3-3, FIFO
The system CK11 is supplied to the write side of the O memory 3-4 and the STC counter 3-5. For example, its frequency is 27 MHz. The transmission CK12 related to the transmission unit 4 is supplied to the header controller 3-9 ′, and the FI
The FO memory 3-2, the read side of the FIFO memory 3-4, the latch 3-6, and the header information generator 3-7 'transmit the transmission CK1 in response to a control signal from the header controller 3-9'.
It operates in synchronization with 2.

[0006] The VENC 3-1 converts the video signal 1 into compressed data information according to the system CK11 and outputs it.
The AENC 3-3 converts the audio signal 2 into compressed data information according to the system CK11 and outputs it, or outputs it as uncompressed data without conversion. These pieces of compressed data information are output instantaneously in synchronization with 27 MHz, but have a data rate smaller than the capacity of the transmission unit 4 on average. These pieces of compressed data information are written into the FIFO memory 3-2 and the FIFO memory 3-4 at 27 MHz, and are synchronized with the transmission / transmission CK12 by the header controller 3-2.
The data is read out in response to the control signal from 9 ′ and converted into the rate of the transmission unit 4.

[0007] The STC counter 3-5 is provided in the system CK1.
This is a counter that operates at 1 and is a clock that is used as a reference on the transmitting side. The latch 3-6 is connected to a header controller 3-9 '.
At this time, the STC counter value generated from the STC counter 3-5 is held based on the control signal
R (System Clock Reference) information. This SCR
The information is transmitted in the transport stream 9 at a substantially constant cycle.
, The period of which is 0.7 seconds at maximum, usually 50 mS
Often around. Here, the header controller 3-9 '
, A header for the SCR is generated from the header information generator 3-7 ', and then the SC
R information is generated. The above-mentioned PID is generated from the header information generator 3-7 ', and subsequently, the corresponding outputs of the FIFO memory 3-2 and the FIFO memory 3-4, which are compressed data information, are generated. These are multiplexed at -10 to become a transport stream 9 'as shown in FIG. 3, which is output from the multiplexing unit 3-10.
Here, a control signal 16 indicating whether the audio data in the transport stream 9 ′ is compressed data or uncompressed data is also output. That is, the transport stream 9 ′ output from the TS creating unit 3 includes the PID, SC
R information, a header for compressed data, and compressed data information are repeated, and finally a data group of, for example, 6.14 Mbps is formed.

[0008] The transmission unit 4 is generally designated by a usable transmission rate in order to use a public line network. Therefore,
The transmission CK to the TS creation unit 3 is supplied from the transmission unit 4. Therefore, in general, the system CK11 and the transmission C
K12 becomes an asynchronous relationship, and FIFO memory 3-2, F
If the IFO memory 3-4 is about to underflow, the header controller 3-9 'inserts and adds meaningless padding data to the transport stream instead of the compressed data, thereby increasing the transmission data. It should be noted that a padding data header is added at the time of insertion.

[0009] The TS analysis unit 5 includes a separation division unit 5-1 and a FI
FO memory 5-2, VDEC (Video Decoder) 5-3, F
IFO memory 5-4, ADEC (Audio Decoder) 5-
5, receiving side STC counter 5-6, latch 5-7, SC
It comprises an R extractor 5-8 and a header analyzer 5-9 '. The transmission section 4 supplies the transmission CK 12 (frequency 6.144 MHz) to the header analyzer 5-9 '. The header analyzer 5-9 'analyzes each PID value from the transmitted transport stream 10', and
The data following the ID information is stored in the FIFO memory 5-2, FI
It outputs a control signal to be taken into the FO memory 5-4 or the SCR extractor 5-8 and a control signal 19 to cause the latch 5-7 to hold the counter value of the receiving STC counter 5-6 at that time. . Where FIFO
Memory 5-2, reading side of FIFO memory 5-4, receiving side STC counter 5-6, VDEC 5-3, ADEC
5-5, the receiving system CK13 (frequency 27 MHz)
z) is supplied.

The VDEC 5-3 has a FIFO memory 5-2.
Decodes and reproduces the original image from the output compressed data information.
Further, the ADEC 5-5 receives the FI signal based on a control signal 17 'indicating compression and non-compression of the audio signal obtained from the transmission side.
It is determined whether to decode and reproduce the output data of the FO memory 5-4 or to output and reproduce the data as it is. When the compression processing is performed, some deterioration occurs.
The TS analyzer 5 also outputs the reproduced video signal 6, the reproduced audio signal 7, the extracted SCR information 14, and the receiving side STC counter value hold output 15.

Next, the configuration of the VCO control unit 8 will be described.
The VCO control unit 8 includes a difference detector 8-1, an AMP (amplifier)
8-2 and LPF 8-3. Difference detector 8
-1 compares the SCR information 14 with the value of the receiving side STC counter value output 15, and calculates an analog error amount e according to the difference.
Is output. Then, the error amount e is converted into an output f whose gain, offset, frequency characteristics and the like are suitable for the control range of the VCO 18 by the AMP 8-2 and the LPF 8-3. The VCO 18 performs an operation of increasing or decreasing the output frequency according to the voltage of the control signal f. VCO control unit 8
Is the receiving side STC counter value hold output 15 and SC
The SCR information 14, which is the value of the R extractor 5-8, is compared, and the receiving system CK13 is controlled so that the difference between the two becomes constant. For example, when the SCR information 14 is larger than the STC counter output 15 on the receiving side, the VCO 18 is controlled so that the frequency of the system CK 13 becomes higher. Conversely, SC
If the R information 14 is smaller than the receiving STC counter output 15, the VCO is set so that the frequency of the system CK13 becomes lower.
18 is controlled.

By repeating this operation, the receiving STC counter 5-6 and the transmitting STC counter 3-6
5, the counting operation is continued while outputting substantially the same value, and the receiving system CK and the transmitting system CK are output.
Are also the same. That is, a clock that moves at the same tempo as the reference clock on the transmission side also exists on the reception side. This can also be used to realize a synchronous operation between video and audio when compressing / expanding them. By the way, in order to reproduce an arbitrary video and audio from a transport stream in which a plurality of video compressed data and audio compressed data or audio uncompressed data are multiplexed, a PID corresponding to the video and audio is searched, As described above, after the search, the data corresponding to the PID is separated and divided. This PID is 13-bit information.
The PID value can be set to any value other than a specific value.

[0013]

In the system according to the prior art, the receiving side does not know whether the multiplexed audio data is compressed data or uncompressed data. Separately,
It is necessary to transmit a control signal indicating whether the audio data is compressed data or uncompressed data to the receiving side, and the transmission configuration of the system becomes complicated and large. In view of these points, the present invention provides a method for encoding and decoding a moving image signal and an audio signal that can automatically determine whether audio data is compressed data or uncompressed data without increasing the complexity of the transmission configuration of the system. The purpose is to realize.

[0014]

According to the present invention, there is provided a method for encoding and decoding an image signal and an audio signal, comprising the steps of: To the only uncompressed data, information indicating whether the data is compressed data or uncompressed data is added, time-division multiplexed, and transmitted as a transport stream. The above additional information is detected, it is determined whether the corresponding data is compressed data or uncompressed data, and based on the result of the determination, the data is decoded by the corresponding decoding processing. The additional information is added as the least significant bit of information for identifying an image signal and an audio signal, which is one of the header information of the transport stream. As a result, there is no need to transmit information indicating whether the multiplexed audio data is compressed data or uncompressed data, separately from the transport stream, from the transmission side to the reception side. Can be simplified.

[0015]

FIG. 1 is a block diagram showing an embodiment of an encoding / decoding system according to the present invention. Where TS
Since the basic configuration and operation of the creating unit 3 are almost the same as those of the conventional system, here, the creation and analysis of multiplexed data of video compressed data and audio uncompressed data, that is, a so-called transport stream will be mainly described. explain. In the TS creating unit 3, for example, video compressed data,
A transport stream in which audio compressed data or audio uncompressed data is multiplexed is created and transmitted. Each PID at that time is as follows. The audio data is uncompressed data. Video compressed data "10000000100010" (1
022 hex) audio data "10000000010001" (1
(011 hex) Next, the analysis of the transport stream will be described. Upon receiving the transport stream 10 transmitted from the transmitting side, the header analyzer 5-9 of the TS analyzer 5 receives the PID in the transport stream 10.
The values "10000000100010" and "100000"
0100X "(X is 1 or 0).

Then, based on the PID value as the search result, the header analyzer 5-9 stores the video data supplied from the separation / division unit 5-1 in the corresponding FIFO memory 5-2.
Then, control is performed so that the audio data is taken into the FIFO memory 5-4. Here, separation and division of audio data and video data are performed using the upper 12 bits of the PID value. Subsequently, the lower 1 bit of the PID value of the audio data is searched. Here, for example, when the lower 1 bit of the PID value is “1”, it indicates that the separated audio data is uncompressed data, and the receiving side firstly receives the PID in the transport stream.
That the audio data corresponding to is uncompressed data. Then, the information 17 is given to ADEC5-5.

ADEC5-5 calculates F based on this information.
If the output of the IFO memory 5-4 is non-compressed data, it is output and reproduced as an output audio signal 7 without decompression. If the lower one bit is "0", the separated and divided audio data is compressed data. in this case,
The ADEC 5-5 decompresses the output of the FIFO memory 5-2, that is, the compressed data, and reproduces the output as an output audio signal 7. According to the above method, it is possible to automatically determine whether the audio data is compressed data or uncompressed data based on the lower 1 bit of the PID value in the transport stream.

[0018]

As described above, according to the present invention, the transmitting side need not transmit information indicating whether the multiplexed audio data is compressed data or uncompressed data to the receiving side separately from the transport stream. Also, the receiving side can construct an encoding / decoding system that can automatically determine whether the audio data in the transport stream is compressed data or uncompressed data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of an encoding / decoding system according to the present invention.

FIG. 2 is a block diagram showing an outline of an encoding / decoding system according to the related art.

FIG. 3 is a schematic diagram showing an outline of a transport stream.

FIG. 4 is a block diagram showing a configuration of a conventional encoding / decoding system.

[Description of Signs] 1: Input video signal 2: Input audio signal 3: T
S creation unit, 3-1: VENC, 3-2, 3-4: FIF
O memory, 3-3: AENC, 3-5: STC on the transmission side
Counter, 3-6: latch, 3-7: header information generator, 3-8: system CK generator, 3-9: header controller, 3-10: multiplexing unit, 4: transmission unit, 5: TS Analysis unit, 5-1: separation division unit, 5-2, 5-4: FIFO memory, 5-3: VDEC, 5-5: ADEC, 5-
6: STC counter on the receiving side, 5-7: latch, 5-8:
SCR extractor, 5-9: header analyzer, 6: output video signal, 7: output audio signal, 8: VCO controller, 8
-1: difference detector, 8-2: AMP, 8-3: LPF,
9, 10: transport stream, 11: transmission side system CK, 12: transmission CK, 13: reception side system C
K, 14: extracted SCR information, 15: reception side STC counter hold value, 17: information signal, 18: VCO.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 7/081 H04N 7/13 7/24

Claims (2)

[Claims] In a method of encoding and decoding an image signal and an audio signal, the transmitting side encodes and compresses these signals into compressed data or uncompressed data of only encoding, which are compressed data or uncompressed data, respectively. Information indicating whether the data is data is added, time-division multiplexed, transmitted as a transport stream, and the receiving side detects the additional information in the received transport stream, and the corresponding data is compressed data. An encoding / decoding method of an image signal and an audio signal, characterized in that it is determined whether the data is present or uncompressed data, and based on the result of the determination, the data is decoded by a corresponding decoding process. 2. The method according to claim 1, wherein said additional information is used to identify an image signal and an audio signal, which are one of header information of said transport stream. Encoding / decoding the image signal and the audio signal, wherein the information is added as the least significant bit of the information.