JPH10234010A - Data encoder, data recorder, data decoder and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To multiplex video data and audio data in an optional rate independently of a transmission rate. SOLUTION: Video data encoded by a video encoder 1 are fed to a code buffer memory 4 and stored. Furthermore, the audio data encoded by an audio encoder 2 are fed to a code buffer memory 5 and stored. A controller 8 compares a sum of a data amount M4 stored in the code buffer memory 4 and a data amount M5 stored in the code buffer memory 5 with a preset reference value, and sets the video data having been stored in the code buffer memory 4 into a video packet in one packet and sets the audio data having been stored in the code buffer memory 5 into an audio packet in the packet when the sum is equal to the reference value. A stream ID that denotes whether a packet is a video packet or an audio packet is set to a header of each packet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, encoding and multiplexing moving image data and audio data, recording the multiplexed data on a recording medium, and decoding and separating data reproduced from the recording medium. The present invention relates to a data encoding device, a data recording device, a data decoding device, and a recording medium suitable for use in such a case.

[0002]

2. Description of the Related Art For example, a recording medium for encoding video data and audio data, multiplexing and recording the same is a CD.
-I is known. FIG. 6 shows a multiplex format in the CD-I.

[0003] As shown in the figure, in CD-I,
Tracks on the disk are divided into a plurality of sectors, and in each sector, 16 sectors (for example, sectors with relative sector numbers 0 to 15) are grouped into one group, and each sector in each group includes predetermined data. It has been made possible to arrange. Therefore, in CD-I, 1
Six types of data can be recorded.

When recording audio data and video data in each sector, for example, a level A stereo (S)
Audio data has relative sector numbers 0, 2, 4,
, 14, and the video teledata is recorded in sectors with relative sector numbers 1, 3, 5,. That is, audio data and video data are interleaved for each sector. Further, monaural audio data (M) is recorded in sectors with relative sector numbers 0, 4, 8, and 12, and video data is recorded with relative sector numbers 1 to 3, 5 to 7, 9, 9 to 11, and 13 to 13 It is recorded in 15 sectors.

At level B, stereo audio data is recorded in sectors having relative sector numbers 0, 4, 8, and 12, and video data is recorded in relative sector numbers 1 and 2.
3, 5 to 7, 9 to 11, and 13 to 15 sectors. On the other hand, monaural audio data is recorded in sectors with relative sector numbers 0 and 8, and video data is recorded in sectors with relative sector numbers 1 to 7, 9 to 15.

At level C, stereo audio data is recorded in sectors with relative sector numbers 0 and 8, and video data is recorded with relative sector numbers 1 to 7,
It is recorded in 9 to 15 sectors. Further, monaural audio data is recorded in a sector having a relative sector number of 0, and video data is recorded in sectors having a relative sector number of 1 to 15.

Audio data and video data are recorded in the same pattern in other groups having relative sector numbers of 16 or later.

[0008] The CD-I is a fixed-rate medium, and has 75 sectors per second. Also,
At the head of each sector, a subheader is provided, and information indicating whether the data contained in the sector is video data or audio data is recorded in the subheader.

[0009]

As described above, the conventional C
DI indicates that the multiplexing of video data and audio data is performed in units of sectors within a group composed of 16 sectors, so that the ratio of multiplexing of video data and audio data is determined by the number of corresponding sectors. Therefore, there is a problem that it is not possible to obtain a simple integer ratio, and that both cannot be multiplexed at a free ratio.

As a result, even if, for example, video data and audio data are processed not at a fixed rate but at a variable rate, the multiplexing ratio of both must be changed roughly in a step-like manner, so that both are efficiently processed. In order to perform multiplexing, the ratio of the transmission (coding) rates of the two must be set to a predetermined value in a stepwise manner in accordance with the adjustable multiplexing ratio.

That is, for efficient multiplexing, the transmission (coding) rates of video data and audio data are
It had to be substantially fixed at a predetermined value.

The present invention has been made in view of such a situation, and it is an object of the present invention to multiplex a plurality of data at an arbitrary ratio.

[0013]

A data encoding apparatus according to the present invention encodes and multiplexes a plurality of data in a first data (for example, video data).
The first detecting means (for example, the code buffer memory 4 of FIG. 1) for detecting the transmission rate of the data, and the second detecting means (for example, the code buffer memory of FIG. 1) for detecting the transmission rate of the second data (for example, audio data) A memory 5); adjusting means (for example, the control device 8 in FIG. 1) for adjusting the multiplexing ratio of the first data and the second data according to the detection results of the first and second detecting means; It is characterized by having.

[0014] The first detecting means and the second detecting means are each constituted by a first or second buffer memory for storing first or second data transmitted at a first or second transmission rate, respectively. be able to.

[0015] The adjusting means may include a sum of the storage amount M1 of the _first data stored in the first buffer memory and the storage amount M2 of the _second data stored in the second buffer memory. And a predetermined reference value D, and the multiplexing ratio of the first data and the second data can be adjusted according to the comparison result.

[0016] The multiplexing amount P ₁ of the first data, the multiplexing amount P ₂ of the second _{data, P 1 = D × M 1} / (M 1 + M 2),
It is possible to set P ₂ = D−P ₁ and put it in the first packet and the second packet of the same pack.

[0017] An additional means for adding information indicating which of the first data and the second data is contained as a header of the packet may be further provided.

Further, the data recording apparatus of the present invention is characterized by comprising recording means (for example, DSM10 in FIG. 1) for recording the data multiplexed by the above-mentioned data encoding apparatus on a recording medium.

Further, the recording medium of the present invention is a recording medium in which a plurality of data are multiplexed and recorded, wherein the data is recorded in units of variable-length packs, and the packs are formed by an arbitrary number of packets. And the packet is characterized by being constituted by an arbitrary number of first packets accommodating the first data and an arbitrary number of second packets accommodating the second data.

In the header of this packet, the packet
Information indicating which of the first data and the second data is contained can be included.

Further, the data decoding apparatus of the present invention has a first
And the header contains any number of packets including information indicating that the first data is contained, the second data, and the header contains the second data. In a data decoding device that separates a plurality of encoded, multiplexed and transmitted data in units of a variable-length pack consisting of an arbitrary number of packets including information indicating that the , The first data and the second data are separated according to the information included in the header.

In the data encoding apparatus according to the present invention, the multiplexing ratio of the first data and the second data is adjusted according to the detection results of the first and second detection means. Therefore, the transmission rates of the first data and the second data can be set to arbitrary values.

In the data recording apparatus of the present invention, the data multiplexed as described above is recorded by the recording means. Therefore, it is possible to provide a recording medium having data multiplexed at an arbitrary ratio as needed.

In the recording medium of the present invention, the first
The pack composed of the first packet and the second packet has a variable length. Therefore, a recording medium in which the first data and the second data are multiplexed at an arbitrary ratio can be easily obtained.

Further, in the data decoding device of the present invention, the type of data recorded therein is determined from the header of a packet constituting a variable length pack.
Therefore, it is possible to reliably separate the first data and the second data.

[0026]

1 and 2 show one embodiment of a data encoding apparatus and a decoding apparatus according to the present invention. In FIG. 1, a video signal is compressed and encoded by a video encoder 1 and a multiplexing device 3.
Is input to the code buffer memory 4 in the memory. The audio signal is compressed and encoded by the audio encoder 2 and input to the code buffer memory 5 of the multiplexer 3.

Output terminals of the code buffer memories 4 and 5 are input terminals E1 and E2 of the switching circuit 6, respectively.
It is connected to the. Output terminal F of switching circuit 6
Is connected to the input terminal of the header adding circuit 7. The output of the header adding circuit 7 is supplied to a digital storage medium (DSM) 10 composed of, for example, a magneto-optical disk, a magnetic disk (hard disk) or the like, and is recorded. The control device 8 receives the system clock output from the multiplexed system clock generation circuit 9 and sequentially connects the input terminals E1 and E2 of the switching circuit 6 to the output terminal F at a predetermined cycle, thereby setting the code buffer memory. Data from 4 or 5 is sequentially taken out and time-division multiplexed.

The control device 8 controls the switching circuit 6 and the header adding circuit 7 so that a bit stream is generated according to the format shown in FIG.

That is, as shown in FIG.
In the multiplexing method G), one multiplexed bit stream is composed of one or more (m + 1 in the figure) PACKs.
And one ISO_11172_end_code. ISO_
11172_end_code is a 32-bit code, which is 0x000001b9 in hexadecimal. Here, the leading 0x represents a hexadecimal number (C language).

One pack includes Pack_Start_Code, SCR
(System Clock Referece), a header composed of MUX_Rate, and one or more (n + 1 in the figure) packets (Packe
t). Pack_Start_Code of the header is 32
The code of the bit is 0x000001b4 in hexadecimal.
The length of the pack is defined as a variable length, but is assumed to be 2048 bytes (fixed) here for convenience of explanation.

One packet is Packet_Start_Code
_Prefix, Stream_ID, Packet_length, PTS (Present
ation Time Stamp), a header composed of DTS (Decoding Time Stamp), and packet data (Code Data). Packet_Start_Code_Prefix is a 24-bit code and is 0x000001. Stream_ID is an 8-bit code and represents the type of packet as shown in FIG. Pack
et_length (16 bits) indicates the length of a subsequent packet (variable length).

In the Code Data of each packet, audio data (in the case of an audio stream) or video data (in the case of a video stream) is recorded. Also, audio st
Ream has 32 types and video stream has 16 different st
Because of the ream id, a plurality of audio signals and video signals up to this number can be multiplexed.

The reserved stream has data such as subtitles. private_stream_1 and private_stream_2
Has no defined use. padding_stream is used to increase the amount of data.

In accordance with the above-mentioned format, the control device 8 performs a header addition and a code reading process using an algorithm as shown in FIG. 5, for example, so that the pack length becomes 2048 bytes.

First, the control device 8 controls the header adding circuit 7
To add a pack header (FIG. 3) (step S1). Then, the written data volume M ₄ in the code buffer memory 4, the sum of written into the code buffer memory 5 data amount _{M 5 (M 4 + M 5} ) is equal to code data quantity D included in one pack Or waits until it becomes larger (step S2). That is, 1
It waits until data enough to be stored in one pack is accumulated in the code buffer memories 4 and 5.

Here, for simplicity, D is a constant, that is, the size of the pack (2048 bytes), and the size of the pack header, the size of each video packet header, and the size of each audio packet header are subtracted. Shall be.

Next, the amount P1 of video data contained in the pack and the amount P of audio data contained in the pack
2 is calculated according to the following equation (step 3). P1 = D × M ₄ / (M ₄ + M ₅ ) P 2 = D−P 1 That is, here, the total amount D of the code data included in the pack is simply distributed according to the ratio of the data amount of each of the code buffer memories 4 and 5. ing.

When the data amount is determined, the control device 8 instructs the header adding circuit 7 to output the video packet header (FIG. 3).
Is output (step S4). Next, the video data of P1 byte is read out from the code buffer memory 4, and
It is output to the SM 10 (step S5). Next, an audio packet header is added (step S6), and P2-byte audio data is read from the code buffer memory 5 and output to the DSM 10. Also, this DSM
To 10, a recording command is input from the control device 8. Thereby, the data input from the multiplexer 3 is recorded on the disk of the DSM 10 (Step S).
7). The above processing is repeated.

When the video encoder 1 encodes video data in a variable length in accordance with the MPEG system in accordance with the complexity of the image, the transmission rate output to the code buffer memory 4 is changed according to the encoding process. Change correspondingly. Similarly, when the audio encoder 2 encodes audio data in a variable length, the transmission rate output to the code buffer memory 5 changes according to the encoding process. However, the code buffer memory 4
And 5 simply store the input data,
Even if the transmission rate changes, no particular problem occurs.

As described above, when the sum of the data storage amounts of the code buffer memories 4 and 5 reaches the value D, in proportion to the storage amounts of the code buffer memories 4 and 5,
The ratio of video data and audio data in one pack is allocated.

As described above, a pack is composed of an arbitrary number of packets, video data is a video packet, audio data is an audio packet,
Each is accommodated. Since the length information (Packet_length) is arranged in the header of each packet, there is no particular problem even if the length (the amount of data of the packet) changes. That is, the video data and the audio data can be multiplexed without any excess or irrespective of the value (ratio) of the ratio (even if the ratio is not a simple integer ratio).

Therefore, regardless of the multiplexing ratio of video data and audio data, the transmission rate (encoding processing rate) from the video encoder 1 to the code buffer memory 4 and the transmission rate from the audio encoder 2 to the code buffer memory 5 The rate (encoding processing rate) can be continuously changed to an arbitrary value.

The data recorded on the disk (DSM 10) in this manner is decoded by the data decoding device shown in FIG. That is, the header separation circuit 22 of the separation device 21 separates the pack header and the packet header from the data read from the DSM 10 and
And the time-division multiplexed data is supplied to the input terminal G of the switching circuit 23.

Output terminals H1, H of the switching circuit 23
2 is connected to input terminals of a video decoder 25 and an audio decoder 26, respectively. The control device 24 of the separation device 21 switches the switching circuit 23 according to the Stream ID of the packet header supplied from the header separation circuit 22.
Input terminals G and output terminals H1 and H2 are sequentially connected to correctly separate the time-division multiplexed data and supply it to the corresponding decoder. That is, the video data is sent to the video decoder 25 and the audio data is sent to the audio decoder 2.
6 are output.

[0045]

As described above, according to the data encoding apparatus of the present invention, in accordance with the detection results of the first and second detection means,
Since the multiplexing ratio of the first data and the second data is adjusted, different data can be multiplexed at an arbitrary ratio regardless of the transmission rate. In other words, an arbitrary transmission rate can be set regardless of the multiplexing ratio.

According to the data recording apparatus of the present invention,
Since the data multiplexed by the above-described data encoding device is recorded on the recording medium by the recording means, it is possible to easily obtain a recording medium in which a plurality of data are multiplexed at an arbitrary ratio. .

Further, according to the recording medium of the present invention, the first data and the second data are recorded in units of variable-length packs, so that a plurality of data can be reliably multiplexed at an arbitrary ratio. Can be realized.

Further, according to the data decoding apparatus of the present invention, the first data and the second data are separated according to the information included in the header, so that the multiplexing is performed at an arbitrary ratio. It is possible to easily separate the plurality of pieces of data.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of a data encoding device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of an embodiment of a data decoding device according to the present invention.

FIG. 3 is a diagram illustrating a format of a bit stream in the embodiment of FIG. 1;

FIG. 4 is a diagram illustrating the stream ID of FIG. 3;

FIG. 5 is a flowchart illustrating the operation of the embodiment in FIG. 1;

FIG. 6 is a diagram showing a conventional CD-I multiplexing format.

[Explanation of symbols]

1 video encoder, 2 audio encoder,
3 multiplexing device, 4,5 code buffer memory,
6 switching circuit, 7 header addition circuit, 8
Controller, 9 multiplexed system clock generator,
10 DSM, 21 separation device, 22 header separation circuit, 23 switching circuit, 24 control device,
25 video decoder, 26 audio decoder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Fig 11B 20/12 102 H04N 5/92 7/32

Claims (11)

[Claims] 1. A data encoding device for encoding and multiplexing a plurality of data, wherein: a first detecting means for detecting a first transmission rate of a first data; and a second transmission of a second data. Second detecting means for detecting a rate, and adjusting means for adjusting the multiplexing ratio of the first data and the second data in accordance with the detection results of the first and second detecting means. A data encoding device, comprising: 2. The first detection means is a first buffer memory for storing the first data transmitted at the first transmission rate, and the second detection means is a second buffer memory. The data encoding device according to claim 1, wherein the data encoding device is a second buffer memory that stores the second data transmitted at a transmission rate of: 3. The storage device according to claim 2, wherein the adjusting unit is configured to store a storage amount M1 of the _first data stored in the first buffer memory and a storage amount of the second data stored in the second buffer memory. _{3. The method according} to claim 1, further comprising: comparing a sum of M2 with a predetermined reference value D, and adjusting a multiplexing ratio of the first data and the second data according to a result of the comparison. 2
3. The data encoding device according to claim 1. Wherein said adjusting means, said multiplexing amount P ₁ of the first data, the multiplexing amount P ₂ of the second data, _{respectively, P 1 = D × M 1} / (M 1 + M ₂₎ data encoding device according to claim 3, characterized in that the P ₂ = D-P _1. 5. The adjusting means multiplexes the data into a variable-length pack, and sets the first data and the second data contained in the pack to P ₁ and P ₂ , respectively. The data encoding device according to claim 4. 6. The pack includes a plurality of packets, wherein the packets include a first packet containing the first data, and a second packet containing the second data. The data encoding device according to claim 5, wherein: 7. The apparatus according to claim 1, further comprising an adding unit for adding, as a header of the packet, information indicating which of the first data and the second data the packet contains. Item 7. The data encoding device according to Item 6. 8. A data encoding apparatus according to claim 1, further comprising: a recording unit that records the data multiplexed and encoded by the encoding apparatus on a recording medium. Characteristic data recording device. 9. A recording medium on which a plurality of data are multiplexed and recorded, wherein the data is recorded in units of variable-length packs, and the packs are constituted by an arbitrary number of variable-length packets. Wherein the packet is composed of an arbitrary number of first packets accommodating first data and an arbitrary number of second packets accommodating second data. . 10. The packet is provided with a header, and the header includes information indicating which of the first data and the second data the packet contains. The recording medium according to claim 9, wherein: 11. A method for accommodating a first data, accommodating an arbitrary number of packets including information indicating that the first data is accommodated in the header thereof, and accommodating the second data, A plurality of packets coded, multiplexed and transmitted in units of a variable-length pack composed of an arbitrary number of packets including information indicating that the second data is accommodated in the header. A data decoding device for separating data, wherein the first data and the second data are separated in accordance with information included in the header.