JP2000358246A - Video decoding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce delay in change-over of coded data which is stored in an interleaved structure by changing the size of a buffer in accordance with a detected operation state. SOLUTION: An coded data output device 2 reads coded data 11 from an coded data storing part 1 in accordance with an address 10 outputted from a reproduction control part 5. The buffer 3 changes the buffer size for storing coded data in accordance with the operation state 12 which is outputted from the control part 5. That is, the size of the buffer 3 is reduced when the reproduction control part 5 confirms that reproduction is of coded data in the interleaved structure. The succeeding read address is analyzed by the control part 5 concerning coded data 15 which is stored in the buffer 3 and designated to an coded data output device 2. A decoding device 4 takes out coded data from the buffer 3, decodes them and outputs a video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video decoding device for reproducing an encoded video signal.

[0002]

2. Description of the Related Art When decoding data encoded by ISO11172 (MPEG1) or ISO13181 (MPEG2), the encoded data read from the encoded data output device is temporarily stored in a buffer, Transfer to the decryption device and decrypt.
By providing the buffer, data stored physically discontinuously can be reproduced seamlessly and continuously. In addition, when an error occurs in the encoded data output device, temporary interruption of data due to error processing can be tolerated. In order to realize the multi-angle described in the video standard of the DVD standard part 3, a data sequence obtained by encoding video from a plurality of angles is interleaved and stored on a disc. In this way, when reproducing the multiplexed and stored coded data, the coded data output device selects a coded data sequence of a desired angle from the interleaved coded data,
It is stored in the read buffer in the form of a stepping stone. After storing the encoded data string read in the form of a stepping stone in a buffer,
By transferring the data to the decoding device, a continuous video without any seam can be obtained.

In order to change the angle seamlessly during reproduction, the read position from the encoded data output device is changed to the read position of the encoded data string of a desired angle.

[0004]

However, since the seamless angle switching is realized by changing the reading position of the coded data string from the coded data output device, the code stored in the buffer is not changed. There will be a delay in outputting the video after angle switching for the reproduction time of the coded data. For this reason, there is a time lag between when the angle switching operation is performed and when the video of the desired angle is output, which gives the user a sense of discomfort.

[0005] In view of the above, it is an object of the present invention to provide a video decoding apparatus in which a delay caused in switching encoded data stored in an interleaved structure is reduced.

[0006]

The video decoding apparatus of the present invention comprises means for detecting an operation state and means for changing the size of a buffer according to the detected operation state.

Thus, when the encoded data is stored in an interleaved state, the size of the buffer is reduced to switch the encoded data sequence, and then the video of the selected encoded data sequence is displayed. The delay until the operation can be reduced.

[0008] The video decoding apparatus of the present invention comprises means for detecting a transfer rate and means for changing the size of a buffer according to the detected transfer rate.

When the encoded data is stored in an interleaved structure, the transfer rate of the encoded data sequence is generally low. By detecting the transfer rate and reducing the size of the buffer when the transfer rate is low, it is possible to reduce the delay from when the coded data sequence is switched to when the video of the selected coded data sequence is displayed.

[0010] The video decoding apparatus of the present invention further comprises means for managing an encoded data string stored in the buffer;
Means for deleting the encoded data string stored in the buffer. With this, when the switching of the encoded data sequence occurs, the encoded data sequence in an appropriate unit is deleted from the encoded data sequences stored in the buffer, and a new encoded data sequence is encoded instead. By reading from the encoded data output device and storing it in the buffer, it is possible to reduce the delay time from when the encoded data sequence is switched to when the video of the selected encoded data sequence is displayed.

[0011]

Next, an embodiment of a video decoding apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of a video decoding apparatus according to the present invention. The video decoding device according to the present invention includes an encoded data storage unit 1, an encoded data output device 2, a buffer 3, a decoding device 4, and a reproduction control unit 5.

The encoded data output device 2 includes a reproduction control unit 5
The coded data 11 is read from the coded data storage unit 1 in accordance with the address 10 output from, and is output. The buffer 3 changes the buffer size for storing encoded data according to the operation state 12 output from the reproduction control unit 5. The next read address is obtained by analyzing the encoded data 15 stored in the buffer 3 by the reproduction control unit 5, and
It is specified to the encoded data output device 2. The decoding device 4
It takes out encoded data from the buffer 3, decodes it, and outputs a video signal 13.

The encoded data used in the multi-angle described in the video standard of the DVD standard part 3 is constituted by interleaving data obtained by encoding video from a plurality of angles in interleave unit units. The interleave unit stores the address of the next interleave unit to be read. At the time of playback, so that only the encoded data of the interleave unit of the selected angle can be read in a stepping stone shape,
An address 10 is output from the reproduction control unit 5 to the encoded data output device 2 for each interleave unit and controlled.
When changing the angle without a seam, the playback control unit 5
, The address of the interleave unit specified to the encoded data output device 2 is changed to the address of the interleave unit of the specified angle. Therefore, the switching to the image in which the encoded data of the new angle is decoded is delayed by the reproduction time of the data stored in the buffer 3. When the speed at which the encoded data output device 2 outputs the encoded data is sufficiently high, the reproduction proceeds with the buffer 3 being almost full. Therefore, the faster the data output of the encoded data output device 2 is, the slower the response of the angle change tends to be.

In the video decoding apparatus according to the present invention, when the reproduction control unit 5 recognizes that reproduction of encoded data having an interleaved structure is to be performed, the size of the buffer 3 is reduced.
As a result, the amount of encoded data stored in the buffer 3 is reduced, so that the time from when the user instructs the angle change to when the video of the specified angle is output can be reduced, and the reaction of the angle change can be reduced. Can be improved.

FIG. 2 is a diagram showing a second embodiment of the video decoding apparatus according to the present invention. The video decoding device according to the present invention includes an encoded data storage unit 1, an encoded data output device 2, a buffer 3, a decoding device 4, a reproduction control unit 5, and a transfer rate detection unit 6. I have. Transfer rate detector 6
Detects the transfer rate of the encoded data to be transferred to the decoding device 4. When the detected transfer rate 14 is high, the size of the buffer 3 is increased, and when the detected transfer rate is low, the size of the buffer 3 is set small.

In general, the transfer rate of encoded data stored in an interleaved structure is low. Therefore, if the video decoding apparatus is configured in this way, the size of the buffer 3 during angle reproduction is reduced. As a result, it is possible to reduce a delay in time from when the angle change is instructed to when the image of the angle after the change is output, and to improve a response when the angle is changed.

As described above, according to the video decoding apparatus of the present invention, when decoding coded data having an interleaved structure, the size of the buffer 3 is set small, so that the user can change the angle. The time from when the command is given until the video of the specified angle is displayed on the screen,
That is, it is possible to reduce dullness in response to the angle change.

FIG. 3 is a diagram showing a third embodiment of the video decoding apparatus according to the present invention. The video decoding device according to the present invention includes an encoded data storage unit 1, an encoded data output device 2, a buffer 3, a decoding device 4, a reproduction control unit 5, and a buffer management table 7. . When reproducing coded data interleaved for multi-angle, the reproduction control unit 5 instructs the coded data output device 2 to specify the read address 10 in units of interleave units. The read coded data 11 is stored in the buffer 3. At this time, information 16 regarding the read interleave unit is stored in the buffer management table 7. When the encoded data is output from the buffer 3 to the decoding device 4, an interleave unit output notification 17 is transmitted to the reproduction control unit 5. Upon receiving the interleave unit output notification 17, the reproduction control unit 5 deletes information on the output interleave unit from the buffer management table 7.

Therefore, the buffer management table 7 stores only information on the interleave unit currently stored in the buffer. When an angle switch occurs, the reproduction control unit 5 issues an interleave unit delete command 18 to the buffer 3 with reference to the buffer management table 7. The buffer 3 deletes the specified interleave unit, and the reproduction control unit 5 reads out the interleave unit of the specified angle as a substitute for the deleted interleave unit from the encoded data output device 2 again.
To be stored. As a result, the encoded data in the buffer 7 which causes a delay when the angle is changed can be deleted and the encoded data of the specified angle can be read again, so that the time until the video of the angle specified by the user is output. Can be shortened.

As described above, according to the video decoding apparatus of the present invention, when the angle is changed, the coded data stored in the buffer 3 is replaced with the coded data of the specified angle. It is possible to shorten the time for reproducing the video, and reduce the dullness of the reaction to the angle change.

[0022]

As described above, the video decoding apparatus according to the present invention comprises a playback control section for outputting a playback state, and a buffer for changing the size in accordance with the playback state. When playing back, the effect of shortening the time from changing the coded data sequence to outputting the video obtained by decoding the coded data sequence after the change to the screen to reduce the buffer size is set. Is obtained.

Similarly, the video decoding apparatus of the present invention includes a buffer for detecting the transfer rate of encoded data and changing the size in accordance with the transfer rate, and sets the buffer small when the transfer rate is low. In the case of playing back interleaved coded data, the effect of shortening the time from changing the coded data sequence to outputting a video obtained by decoding the coded data sequence after the change to the screen is obtained. Can be

Further, since the video decoding apparatus of the present invention includes a buffer management table and means for operating the encoded data stored in the buffer, when reproducing encoded data having an interleaved structure, This has the effect of shortening the time from changing the encoded data sequence to outputting a video obtained by decoding the changed encoded data sequence to the screen.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of a video decoding device of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the video decoding device of the present invention.

FIG. 3 is an explanatory diagram of a third embodiment of the video decoding device of the present invention.

[Explanation of symbols]

1 coded data storage unit 2 coded data output device
3 buffer, 4 decoding device, 5 playback control unit, 6
Transfer rate detector, 7 ... buffer management table, 10 ...
Address, 11: encoded data, 12: reproduction state, 13
... video signal, 14 ... transfer rate, 15 ... encoded data,
16: Information on interleave unit, 17: Interleave unit output notification, 18: Interleave unit deletion instruction.

Continuation of the front page (72) Inventor Manabu Sasaki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Visual Information Media Division of Hitachi, Ltd. 5C053 FA24 GB02 GB17 GB37 GB38 HA31 KA04 KA24 5C059 KK11 MA00 SS13 TA00 TA71 TC37 UA05 UA34 UA36 UA37

Claims (3)

[Claims] 1. An apparatus for decoding an encoded video signal, comprising: an encoded data output device for reading stored encoded data; a buffer for temporarily storing the encoded data; A video decoding device, comprising: a decoding device for decoding data; and changing a size of a buffer according to an operation state. 2. An apparatus for decoding an encoded video signal, comprising: an encoded data output device for reading stored encoded data; a buffer for temporarily storing the encoded data; A video decoding device, comprising: a decoding device that decodes data; and changing a size of a buffer according to a transfer rate of encoded data. 3. An apparatus for decoding an encoded video signal, comprising: an encoded data output device for reading stored encoded data; a buffer for temporarily storing the encoded data; Video decoding comprising a table for managing stored encoded data, and a decoding device for decoding the encoded data, wherein the encoded data stored in the buffer is deleted as necessary. Device.