JP3487513B2 - Video / audio coding apparatus, video / audio decoding apparatus, video / audio coding / decoding system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention encodes images and sounds,
The present invention relates to a video / audio code decoding system for decoding.

[0002]

2. Description of the Related Art In a method for multiplexing and reproducing data such as image and sound, a coding device and a decoding device are equipped with local clocks, and when coding, a coding device for image and sound data. There is a method of synchronizing the data by adding the value of the local clock of (1) and using the value of the clock added to the decoding device local clock and the data in the decoding device.

In order to synchronize with this method, it is necessary to match the value of the clock of the decoding device with the value of the clock of the encoding device. Therefore, the encoding device needs to teach the decoding device the initial value of the clock at the beginning of the data. Among these conventional devices, the initial value of the clock in this encoding device has been used only for the purpose of providing the internal clock of the decoding device with the initial value.

[0004]

[Problems to be Solved by the Invention] As described above,
Conventionally, when it is about to start transmitting an encoded image or audio signal from the video / audio encoding device to the video / audio decoding device, it is necessary to match the internal clocks provided for both to synchronize them. . In this case, information of the current time of the internal clock is arbitrarily transmitted from the video / audio encoding device to the video / audio decoding device for synchronization. In other words, the information on the current time can be used only for the information that the two are synchronized.

The present invention has been made in view of the above-mentioned problems, in which time information for synchronizing the encoding process and the decoding process is provided with additional information, and the synchronization is performed from this time information. Video / audio coding / decoding system capable of not only taking but also processing based on additional information , and this system
It is an object of the present invention to provide a video / audio decoding device and a video / audio encoding device used in 1 .

[0006]

[Means for Solving the Problems ]
Therefore, the video / audio encoding device of the present invention generates time information.
Time information generator and input image and audio signals
While referring to the time information from the time information generator,
A coding unit for coding and generating a coded signal;
From the encoded signal and the time information generating unit
Generates an encoded bitstream by multiplexing time information
And a multiplexing unit for outputting the time information.
A value containing additional information is issued as the initial value of the time information.
It is characterized by making it live. In addition, the above-mentioned video and audio code
In the digitizing device, the initial value of the time information and its
It has a storage unit that stores the meaning of the value and generates the time information.
The section refers to the storage section and stores the value corresponding to the meaning.
It is good to set it as the initial value of the time information.
Yes. Further, the storage unit stores the initial value of the time information and its value.
Performed on the receiving side of the encoded bitstream indicated by the value
It has a storage unit that stores the type of processing you want to perform.
It may be a sign. Also, the multiplexing unit may
In addition to the coded signal and the time information,
Used in the processing corresponding to the initial value of the time information
The additional information may also be multiplexed. Starting
The Ming video and audio decoding device is transmitted from the video and audio encoding device.
Time information and code from the received encoded bitstream
A separation unit for extracting the encoded signal and the time information based on the time information.
And a time information generator that sets the time
Information extraction to extract additional information included in the initial value of
Section and the time information of the time information generation section,
Decoding of encoded signal to obtain image signal and audio signal
And a chemical conversion unit. The image / audio decoding device of the present invention
Encoded bit stream transmitted from speech encoder
Separation unit for extracting time information and encoded signal from the frame
And set the time to the value of the time information and count the time.
Depending on the time information generation unit to be set and the initial value of the time information
And a time information of the time information generating unit
Image signal and sound by decoding the coded signal with reference to
And a decoding unit for obtaining a voice signal. Also, the separation unit
Is the coding bit transmitted from the video / audio coding device.
Time information, encoded signal, and additional information from the stream
The processing unit extracts the time using the additional information.
Characterized by performing processing corresponding to the initial value of information
May be. The video / audio decoding system of the present invention
Image and sound are encoded and generated by the first time information generator.
And a coding device for transmitting the time information together with the coding device.
Second time information based on the time information transmitted from the device.
Decode the coded image and sound by adjusting the information generator
And audio / video decoding system including decoding device
In the above, the first time information generating unit is
The type of processing you want the
Remember, the decoding device uses the initial value of the time information.
Generate a value corresponding to the type of processing you want to execute,
The decryption device performs processing corresponding to the initial value of the time information.
And a processing unit that executes the processing.

[0007]

The video / audio encoding device includes the initial value of the time information in the initial value.
This additional information can be selected by selecting the desired additional information from the memory.
The initial value of the time information corresponding to
Generated in raw part, put on bitstream and image
Send to the voice decoding device. Image and audio decoding apparatus that received this, as well as to adjust the second time information generating unit based on time information processing on the basis of the additional information <br/> corresponding to the time information. Therefore, the time information for synchronizing is not only used as the synchronization information,
It can also be used at the same time as additional information for causing the processing device to perform processing .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a video / audio encoding / decoding system using the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a video / audio encoding device using the present invention, and FIG. 2 is a block diagram showing a configuration of a video / audio decoding device. Briefly, moving images and audio data encoded by the image and audio encoding device are transmitted through a transmission path or, for example, a hard disk,
After being stored in a storage medium such as a CD-ROM, it enters the image / sound decoding device, is decoded into a moving image or sound, and is output as a bit stream.

In this embodiment, in order to time-synchronize the input image or voice with the output moving image or voice, the time when the moving image or voice enters the image / audio encoding device, the encoded image or voice data is the image. The time of leaving the audio encoding device is recorded as the value of the internal clock and added to the encoded image and audio data. Here, the internal clock is, for example, 90-kHz, binary 3
It is supposed to be a 3-digit counter.

The video / audio decoding device performs decoding and display while referring to the value of the time information sent as the information of the internal clock. In this case, first send the internal clock controller of the video / audio encoder before sending the video / audio data.
The value of 6 is sent to the video / audio decoding device as the initial value t0 of the time information, and the values of the internal clocks of the video / audio encoding device and the video / audio decoding device are matched. Here, the initial value t0 of the time information
Is the internal time at the start of encoding in the video and audio encoding device.
Value and internal clock at the start of decoding by the video / audio decoding device
Any value may be used as long as the values of are the same. In the present invention
Not only can you set the time like this, but this time
The initial value t0 of the information is characterized by including additional information .

The above contents will be described below with reference to FIGS. 1 and 2. First, as shown in FIG. 1, an image signal is externally input to the digital signal converter 1, and an audio signal is externally input to the digital signal converter 3. The current time information is input to the digital signal converting units 1 and 3 from the internal clock controller 6, and the image signal and the audio signal are converted into digital signals together with the time information. The converted digital signals are input to the encoding units 2 and 4, respectively, encoded together with the time information of the internal clock controller 6, and input to the multiplexing unit 5.

The coded image signal and audio signal input to the multiplexing unit 5 are multiplexed with the current time information of the internal clock controller 6 and output. The output multiplexed signal is input to the video / audio decoding apparatus shown in FIG. 2 via, for example, a transmission path. The input signal is decoded by the system decoding unit 11, the time information in the multiplexed signal is taken out, and is input to the internal clock controller 14. Based on the input time information, the internal clock controller 14 adjusts the clock and synchronizes with the video / audio encoding device. On the other hand, the system decoder 11, outputs encoded data of the image <br/> image signal extracted from the multiplexed signal to the decoder 12, the decoding section 13 the encoded data of audio signals Output . Decryption unit
The image signals and audio signals input to 12 and 13 are decoded by the decoding units 12 and 13 and output to the outside. At this time, it is supposed to be synchronized and output based on the adjusted time information from the internal clock controller 14. As described above, the video / audio encoding / decoding devices shown in FIGS. 1 and 2 are configured so that the internal clock controllers 6 and 14 respectively provided in them are adjusted according to the time information generated from the internal clock controller 6. ing. Further, according to the present invention, the reference time information is first transmitted to the video / audio decoding device before the encoded video signal or audio signal is transmitted from the video / audio encoding device. At this time, since this time information is information for synchronizing the video and audio encoding and decoding devices, it is possible to set and transmit an arbitrary time even if it is not the current time. By applying this point, a storage unit such as a memory is provided in common inside the internal clock controllers 6 and 14, and according to this time information, that is, “10:00” or “11:00”, for example.
Corresponding to the time such as "0", various processing contents in this system are divided into cases and stored as additional information . Then, before starting to transmit the encoded image or audio, the image-audio encoding device selects various processing contents to be transmitted to the image-audio decoding device and outputs time information corresponding to the selected processing contents in the internal clock controller 6. The time is read from the storage unit and the internal clock controller 6 is adjusted to this time information.
The read time information is transmitted to the video / audio decoding device and input to the internal clock controller 14. The internal clock controller 14 adjusts the internal clock according to this time information, and reads out various processing contents in the system corresponding to the internal clock from the storage unit in the internal clock controller 14.
In this way, the processing of data and the like can be performed according to the processing content read by using the time information.

In the conventional example, the video / audio decoding apparatus performs the process 21 of reading the initial value t0 of the time information as in the conventional example of FIG. 3, and then sets the initial value t0 of the time information in the internal clock 22. row decoding of image voice processing from I line
U In the present embodiment, as in the present invention of FIG.
After performing the process 23 of reading the value t0, the first time information
Performs 24 processes to set the period value t0 to the internal clock,
Read additional information I included in the initial value t0 of the time information
After the processing of step 25 is performed, the video / audio is decoded.

[0014] In this embodiment, the bit data stream is the format of FIG. 4, for example, of 32-bit star
33 bits are used to represent the initial value 32 of the time information following the code 31 . Further, the additional information 34 is ignored in normal decoding.

Conventionally, for example, the initial value t0 of the time information is simply sent as the value of the internal clock as in the case of t0 = 000000000000000000001001110010111 (1).

Here, as an example, other information I is added to this data.
When assigning the identification number as, the encoding device uses t0 as the identification number. For example, if the identification number is 3629 (2), the value of t0 is set to the number (2). If expressed in bits, t0 = 000000000000000000000111000101101 (3). The video / audio decoding apparatus performs the processing of 23 following the processing of 22 of FIG. 3 to obtain the number (2) as other information I from t0.

As another example, when a symbol of a character string is attached to this data, the encoding device digitizes the character string and sets the value as the initial value t0 of the time information . For example, if the symbol = “AZ19” (4), the initial value t0 of the time information uses 415a3139 (hexadecimal notation) (5) in which the character string (4) is an ASCII code (t). If t0 is displayed in bits, t0 = 001000001010110100011000100111001 (6). In the video / audio decoding device, 23, 24 and 2 in FIG.
The processing of step 5 is performed, and the initial value t0 of the time information is set in the internal clock to obtain the character string (4). A video / audio decoding device that does not know that the processing in the above two columns has been added has a time information
Since the initial value t0 of the information is treated only as the initial value of the time information , the number (2) and the character string (4) cannot be obtained. However, subsequent decryption can be performed.

As another example, the additional information shown in FIG.34
(Eg subtitles etc.) encrypted by eg RSA encryption
Has beenGive a case. For RSA encryption, follow the procedure below.
Better encryption and decryption. RSA encryption is a positive key
An integer n and a positive integer r are used. n is the two elements p and q
Therefore, it is made by the equation (7).

N = pq (7) Next, r is chosen to be relatively prime with the value of equation (8). (P-1) (q-1) (8) The plaintext a is encrypted by the equation (9).

B a ^r (mod n) (9) This is the encryption procedure. Here, the mod of equation (9)
n means the remainder divided by n (the same applies hereinafter).

The decryption procedure is as follows. For decoding, it is first necessary to know that n is the product of p and q as in equation (7). Using p, q, and r, s for decoding is obtained by the following procedure. First, the formula (1
0), integers u, v, x, y satisfying (11) are obtained.

Ur + v (p-1) = 1 (10) xr + y (q-1) = 1 (11) Here, when the difference between the equations (10) and (11) is taken, the equation (12) is obtained.
Becomes

(U−x) r = −v (p−1) + y (q−1) (12) The left side of the equation (12) is the greatest common divisor d of (p−1) and (q−1). Divisible. Since r is selected as a prime number from (p-1) and (q-1), (u-x) is a multiple of d. Therefore, the integers w and t are taken to obtain the equation (13).

U−x = w (p−1) + t (q−1) (13) The formula (13) is transformed into the formula (14). u−w (p−1) = x + t (q−1) (14) Then, the value of Expression (14) is s. s is needed (p
Reduce by the least common multiple of -1) and (q-1).

Equation (10) is obtained by multiplying the left side of Equation (14) by r.
Is substituted, rs = ru + rw (p−1) = 1− (rw + v) (p−1) 1 (mod p−1) (15) Similarly, the right side of equation (14) is multiplied by r to obtain equation (11). Substituting results in rs = rx + rt (q−1) = 1 + (rt−y) (q−1) 1 (mod q−1) (16). Since the ciphertext is formula (9),

[0026]

[Equation 1]

[0027]

[Equation 2] Becomes That is, if s is obtained from n and r, the plaintext a is obtained by decrypting the ciphertext b. Also, instead of the formula (9), the ciphertext creator

[0028]

[Equation 3] If the cipher is created as, the decryption person can obtain the equation (17), the equation (1
From 8) using only n and r (without knowing p and q)

[0029]

[Equation 4] Can be obtained. Since the operation of the equation (21) can be performed only by an encoding device capable of producing s, that is, an audiovisual encoding device that knows p and q, it is called a digital signature.

In the present embodiment, of the keys n and r, the key n is known in advance to the image / audio decoding device including the p and q of n, and the key r is the image / audio encoding device. On the side, the initial value t0 of the time information is sent from the video / audio encoding device to the video / audio decoding device. The internal clock controller 14 of the video / audio decoding device is designated as 23 , 24, 2 in FIG.
The key r is obtained from the process of 5 , and the internal controller 14 creates s from the previously known p and q using the equations (10) to (14). The additional information 34 is obtained by decrypting the encryption using the equation (19) using the s.

For example, it is assumed that the additional information 34 is a character string "hello world!" (22). If this is converted into ASCII code, it will be 68656c6c6f2077666f726c6421 (23) in hexadecimal notation. This is divided into blocks of, for example, three digits, and each block is encrypted. In this example, n = 4891 (24) p = 67 (25) q = 73 (26) r = 13 (27). When the number (23) is calculated by dividing the number (23) by 3 digits, 07f312410fb10cd809d801930fb1030c (28) is obtained in hexadecimal notation as a cipher. Here, the number (24) is 131b in hexadecimal, so some of the encrypted ones have four digits in hexadecimal. Therefore, the number (28) has four digits in hexadecimal number per block. And the encoding device is the additional information I
The value of the number (27) is used as the initial value t0 of the time information . If expressed in bits, t0 = 000000000000000000000000000001011 (29).

The additional information 34 is encrypted, the key
The value of r is written as the initial value t0 of the time information, the value of the key n is 4891, which is the product of 67 and 73,
A video / audio decoding device that knows the equations (10) to (1
If s is obtained by using 4) and is decoded from the equation (19), the number (23) can be obtained again, and (28) can be read as the additional information 34 to obtain the character string (22). The video / audio decoding device that does not know the value of the key n knows that the additional information 34 is encrypted if the video / audio decoding device that knows the value of the key n and does not know the values of p and q. Additional information
I can't get 34 . Additional information during normal playback
34 is ignored, and the initial value t0 of the time information is 21 in FIG.
22 is performed and only normal reproduction is performed.

Also, consider an example in which a digital signature is made using equations (24) to (27). Of the initial value t0 of the time information, the upper 16 bits are r and the lower 17 bits are equation (20).
Of b. b is the first two digits of the last two digits when the number (23) is divided into three digits and displayed in binary.
56 blocks (all blocks if there are no 256 blocks)
It is assumed that the processing of Expression (20) is performed with the sum of a as a.
In the present embodiment, when the above processing is applied to the number (23), a = 11 (30) is obtained. Therefore, if equation (14) is applied to this, b = 421 (31) is obtained. Using this, the initial value t0 of the time information is expressed in bits as t0 = 00000000000010110000110100101 (32).

The image / sound decoding apparatus is composed of 23 , 24, and
By performing the processing of 25, the numbers (27) and (31) are obtained. Using this, the number (30) is obtained from the equation (21). Additional information above
After obtaining several (29) performs the processing in Embodiment obtaining 34,
When the number obtained by dividing the number (23) into three digits is displayed in binary, the sum of the first 256 blocks (all blocks if there are no 256 blocks) of the lower two digits is calculated, and this is the number (3
If it agrees with 0), it turns out that this data is from a person who knows p and q. Of course, the time information
The initial value t0 is only r as in the equation (29), and the additional information
It is also possible to put a digital signature in 34 .

[0035]

As described above in detail, according to the present invention, the time information included in the coded data of the image or the sound is recorded.
Then, add additional information other than the time information to the initial value of the time information.
By including it, processing using additional information on the decoding device side
It can be executed. Also, this additional information
Even if the decoding device does not understand
Since it is possible to decode the image and sound by taking them, it is possible to flexibly correspond to various kinds of equipment.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Fig. 2] Fig. 2 is a block diagram of a video / audio decoding device of the present invention and a conventional example.
The figure which showed the operation | movement contrast of the timepiece clock controller.

FIG. 3 is a diagram showing a comparison between operations of the present invention and a conventional example.

FIG. 4 is a diagram showing one format of a bitstream of the present invention.

[Explanation of symbols]

1, 3 ... Digital signal converter 2, 4 ... Encoder 5
... Multiplexing unit 6, 14 ... Internal clock controller 11 ... System decoding unit 12, 13 ... Decoding unit

Claims (8)

(57) [Claims] 1. A generation unit for generating additional information, and an initial value of time information corresponding to the additional information.
A time information generating section for generating a value, an encoding section for encoding an input image signal or audio signal with reference to the time information from the time information generating section to generate an encoded signal, the encoding section And a multiplexing unit that multiplexes the coded signal obtained in step 1 and the time information from the time information generating unit to generate and output a coded bit stream. 2. An initial value of time information and an additional value of the value
A storage unit for storing information, a selection unit for selecting additional information, and an additional unit selected by the selection unit with reference to the storage unit.
The value corresponding to various information is generated as the initial value of the time information.
A time information generating section for causing the input image signal and audio signal to be coded by referring to the time information from the time information generating section to generate a coded signal; And a multiplexing unit that multiplexes the coded signal and the time information from the time information generating unit to generate and output a coded bit stream. 3. The storage unit includes a storage unit that stores an initial value of the time information and a type of processing desired to be executed on the receiving side of the encoded bitstream indicated by the value. Item 2. The video / audio encoding device according to Item 2 . 4. The multiplexing unit multiplexes, into the bitstream, in addition to the coded signal and the time information, additional information used in a process corresponding to an initial value of the time information. The image / audio encoding device according to claim 3. 5. A demultiplexing unit that extracts time information and a coded signal from a coded bit stream transmitted from a video / audio coding apparatus, and a time information generation unit that sets the time based on the time information. An information extraction unit that extracts additional information included in the initial value of the time information, and obtains an image signal and an audio signal by decoding the coded signal with reference to the time information of the time information generation unit. A video / audio decoding device having a decoding unit. 6. A demultiplexing unit for extracting time information and a coded signal from a coded bit stream transmitted from a video / audio coding apparatus, and setting a time as a value of the time information to count the time. Corresponds the time information generator with the initial value of the time information and the processing content to be executed.
A storage unit that stores the first time information, a processing unit that performs processing associated with the initial value of the time information, and decodes the coded signal by referring to the time information of the time information generation unit to generate an image signal and an audio signal. A video / audio decoding device comprising: a decoding unit for obtaining a signal. 7. The demultiplexing unit extracts time information, a coded signal, and additional information from a coded bit stream transmitted from a video / audio coding device, and the storage unit initializes the time information. Execute using the value and the additional information
In association with a processing content, the processing unit uses the additional information, versus the value of the initial value of the time information
7. The video / audio decoding device according to claim 6, wherein the video / audio decoding device performs a corresponding process. 8. An encoding device which encodes an image or audio and transmits the encoded image and audio together with the time information generated by a first time information generating unit, and a second encoding device based on the time information transmitted from the encoding device. In a video / audio coding / decoding system including a decoding device that adjusts a time information generation unit to decode the coded image or audio, the first time information generation unit is executed by the decoding device. The type of processing desired to be performed and a value corresponding thereto are stored, a value corresponding to the type of processing desired to be executed by the decoding device is generated as an initial value of time information, and the decoding device is A video / audio encoding / decoding system comprising: a processing unit that executes a process corresponding to an initial value of time information.