Variable length coded data processing method and device for performing the same method

• US 6,154,494 A
• Filed: 04/21/1998
• Issued: 11/28/2000
• Est. Priority Date: 04/22/1997
• Status: Expired due to Term

• Current Assignee: JVC Kenwood Corporation
• Original Assignee: Victor Company of Japan Limited (JVC Kenwood Corporation)
• Inventors: Kobari, Harukuni, Sugahara, Takayuki, Suzuki, Junzo
• Primary Examiner(s): LIN, BRYAN T
• Application Number:
  US09/063,845
• Time in Patent Office: 952 Days
• Field of Search: 375/240, 375/240.01, 375/240.02, 375/240.03, 375/240.04, 375/240.05, 375/240.23, 382/246, 341/67, 348/384.1, 348/390.1, 348/404.1, 348/419.1
• US Class Current: 375/240.23
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/2401 Monitoring of the client buffer
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities

Abstract

Among a first and second video data each being variable length coded data such that an occupancy of a decoder buffer is neither overflown nor underflown, having an end code at a rear end thereof and being comprised of a plurality of compressed portion data, a value related to a buffer occupancy at a decoding timing of the last picture of the first video data is compared by an invalid data amount calculator 13 with the buffer occupancy at the decoding timing of the first picture of the second video data. According to a data amount corresponding to a difference between the occupancies when the result of comparison is a predetermined one, the invalid data of this data amount is added by an invalid data adder 14 to the last picture of the first video data and the second video data is connected by a video data connector 15 to the first video data.

Claims

1. A variable length coded data processing method, in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are coupled and output to a buffer of a decoder, comprising the steps of:

deleting the end code of the first variable length coded data;

calculating an invalid data of an amount corresponding to a result of comparison of a value related to a buffer occupancy at a decoding timing of a last compressed portion data of the first variable length coded data with a buffer occupancy at a decoding timing of a first compressed portion data of the second variable length coded data;

adding the calculated invalid data to the last compressed portion data of the first variable length coded data; and

coupling the second variable length coded data thereto and outputting it to the decoder buffer.

2. A variable length coded data processing method as claimed in claim 1, wherein the value related to the buffer occupancy at the decoding timing of the last compressed portion data of the first variable length coded data is represented by (OC-DB+IB) where OC is the buffer occupancy of the last compressed portion data of the first variable length coded data at the decoding timing thereof, DB is the amount of code of the last compressed portion data and IB is the amount of code input to the decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded, and the data amount of the invalid data is represented by {(OC-DB+IB)-NOC} when NOC<

(OC-DB+IB) and is 0 when NOC≧

(OC-DB+IB), where NOC is the buffer occupancy of a first compressed portion data of the second variable length coded data at the decoding timing thereof.

3. A variable length coded data processing method as claimed in claim 1, wherein the compressed portion data is a picture of a frame compression difference picture data and each of the first and second variable length coded data is a video data composed of a plurality of pictures.

4. A variable length coded data processing method, in which, after a coefficient obtained by an orthogonal transform of an input signal is quantized, a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data such that an occupancy of a buffer of a decoder does neither overflow nor underflow are coupled and output to the buffer of the decoder, comprising the steps of:

deleting the end code of the first variable length coded data;

calculating an amount of deleted code of a data amount of a difference value between a value related to the buffer occupancy at a decoding timing of the last compressed portion data of the first variable length coded data and the buffer occupancy at the decoding timing of the first compressed portion of the second variable length coded data when the value related to the buffer occupancy at a decoding timing of the last compressed portion data of the first variable length coded data is smaller than the buffer occupancy at the decoding timing of the first compressed portion of the second variable length coded data;

deleting a code corresponding to an A.C. component of data described in a predetermined number of compressed portion data including at least the last compressed portion data of the first variable length coded data by the amount of deleted code; and

coupling the second variable length coded data to the first variable length coded data.

5. A variable length coded data processing method as claimed in claim 4, wherein the value related to the buffer occupancy at the decoding timing of the last compressed portion data of the first variable length coded data is represented by (OC-DB+IB) where OC is the buffer occupancy of the last compressed portion data of the first variable length coded data at the decoding timing thereof, DB is the amount of code of the last compressed portion data and IB is the amount of code input to the decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded, and the data amount of invalid data is represented by {NOC-(OC-DB+IB)} only when NOC>

(OC-DB+IB) and is 0 when NOC≦

(OC-DB+IB), where NOC is the buffer occupancy of an initial compressed portion data of the second variable length coded data at the decoding timing thereof.

6. A variable length coded data processing method as claimed in claim 4, wherein the compressed portion data is a picture of a frame compression difference picture data and each of the first and second variable length coded data is a video data composed of a plurality of pictures.

7. A variable length coded data processing method, in which, after a coefficient obtained by an orthogonal transform of an input signal is quantized, a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data such that an occupancy of a buffer of a decoder does neither overflow nor underflow are coupled and output to the buffer of the decoder, comprising the steps of:

deleting the end code of the first variable length coded data;

coding data described in a predetermined number of compressed data including at least the last compressed portion data of the first variable length coded data under a condition that a motion vector is 0 and a motion compensated error data is 0 when a value related to the buffer occupancy at a decoding timing of the last compressed portion data of the first variable length coded data is smaller than the buffer occupancy at the decoding timing of the first compressed portion of the second variable length coded data; and

coupling the second variable length coded data to the first variable length coded data.

8. A variable length coded data processing method as claimed in claim 7, wherein the compressed portion data is a picture of a frame compression difference picture data and each of the first and second variable length coded data is a video data composed of a plurality of pictures.

9. A variable length coded data processing device in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are coupled and output to a buffer of a decoder, comprising:

an end code remover for deleting the end code of the first variable length coded data;

a calculator for calculating an invalid data of a data amount corresponding to a result of comparison of a value related to a buffer occupancy at a decoding timing of a last compressed portion data of the first variable length coded data, the end code thereof being deleted by said end code remover, with a buffer occupancy at a decoding timing of a first compressed portion data of the second variable length coded data;

an adder for adding the invalid data calculated by said calculator to the last compressed portion data of the first variable length coded data of which the end code is deleted ; and

a connector for coupling the second variable length coded data to the first variable length coded data added with the invalid data from said adder and outputting it to said decoder buffer.

10. A variable length coded data processing device as claimed in claim 9, wherein said calculator calculates the data amount of the invalid data by {(OC-DB+IB)-NOC} when NOC<

(OC-DB+IB) and is 0 when NOC≧

(OC-DB+IB), where OC is the buffer occupancy of the last compressed portion data of the first variable length coded data at the decoding timing thereof, DB is the amount of code of the last compressed portion data, IB is the amount of code input to said decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded and NOC is the buffer occupancy of an initial compressed portion data of the second variable length coded data at the decoding timing thereof.

11. A variable length coded data processing device as claimed in claim 9, wherein the compressed portion data is a picture of a frame compression difference picture data and each of the first and second variable length coded data is a video data composed of a plurality of pictures.

12. A variable length coded data processing device as claimed in claim 11, wherein the last scene of the first variable length coded data is coded to a still picture or a picture which can be approximated to a still picture.

13. A variable length coded data processing device as claimed in claim 9, wherein the coupling of the first and second variable length coded data is repeated continuously for a plurality of variable length coded data for a predetermined time.

14. A variable length coded data processing device in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are variable length coded such that an occupancy of a buffer of a decoder does neither overflow nor underflow after a coefficient obtained by an orthogonal transform of an input signal, coupled and output to the buffer of the decoder, comprising:

a memory circuit for preliminarily storing the buffer occupancy OC of the last compressed portion data of the first variable length coded data at the decoding timing thereof, the amount DB of code of the last compressed portion data, the amount IB of code input to said decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded and the buffer occupancy NOC of a first compressed portion data of the second variable length coded data at the decoding timing thereof, as a coding information;

an end code remover for deleting the end code of the first variable length coded data;

a calculator for calculating, on the basis of the coding information read out from said memory circuit, a value represented by (OC-DB+IB), comparing the latter value with the buffer occupancy NOC and calculating an amount of delete code as {(OC-DB+IB)-NOC} when NOC>

(OC-DB+IB) and 0 when NOC≦

(OC-DB+IB);

a code remover for deleting a code corresponding to an A.C. component of data described in a predetermined number of compressed portion data including at least the last compressed portion data of the first variable length coded data derived from said end code remover, by the amount of delete code input from said calculator; and

a connector for coupling the second variable length coded data to the first variable length coded data output from said code remover.

15. A variable length coded data processing device as claimed in claim 14, wherein said calculator further calculates a value represented by {(OC-DB+IB)-NOC} when NOC<

(OC-DB+IB) and 0 when NOC>

(OC-DB+IB) as an invalid data amount, and further comprising an invalid data adder for adding the invalid data having the invalid data amount input from said calculator to the last compressed portion data of the first variable length coded data output from said code remover or said transform means and supplying a result to said connector.

16. A variable length coded data processing device as claimed in claim 14, wherein the compressed portion data is a picture of a frame compression difference picture data and each of the first and second variable length coded data is a video data composed of a plurality of pictures.

17. A variable length coded data processing device as claimed in claims 14, wherein the coupling of the first and second variable length coded data is repeated continuously for a plurality of variable length coded data for a predetermined time.

18. A variable length coded data processing device in which a first and second variable length coded data having end codes at rear ends thereof and each comprised of a plurality of compressed portion data are variable length coded such that an occupancy of a buffer of a decoder does neither overflow nor underflow after a coefficient obtained by an orthogonal transform of an input signal, coupled and output to the buffer of the decoder, comprising:

a memory circuit for preliminarily storing the buffer occupancy OC of the last compressed portion data of the first variable length coded data at the decoding timing thereof, the amount DB of code of the last compressed portion data, the amount IB of code input to said decoder during a time period from a time at which the last compressed portion data is decoded to a time at which a next compressed portion data is decoded and the buffer occupancy NOC of a first compressed portion data of the second variable length coded data at the decoding timing thereof, as a coding information;

an end code remover for deleting the end code of the first variable length coded data;

a calculator for calculating, on the basis of the coding information read out from said memory circuit, a value represented by (OC-DB+IB), comparing the latter value with the buffer occupancy NOC and setting a code transform flag to a predetermined value only when NOC>

(OC-DB+IB);

transform means for coding data described in a predetermined number of compressed portion data including at least the last compressed portion data of the first variable length coded data output from said end code remover under a condition that a motion vector is 0 and a motion compensated error data is 0 when the code transform flag output from said calculator is the predetermined value; and

a connector for coupling the second variable length coded data to the first variable length coded data output from said code remover.

19. A variable length coded data processing device as claimed in claim 18, wherein said calculator further calculates a value represented by {(OC-DB+IB)-NOC} when NOC<

(OC-DB+IB) and 0 when NOC>

(OC-DB+IB) as an invalid data amount, and further comprising an invalid data adder for adding the invalid data having the invalid data amount input from said calculator to the last compressed portion data of the first variable length coded data output from said code remover or said transform means and supplying a result to said connector.

20. A variable length coded data processing device as claimed in claim 18, wherein the compressed portion data is a picture of a frame compression difference picture data and each of the first and second variable length coded data is a video data composed of a plurality of pictures.