WO1998014011A1 - Video coding method and apparatus with periodic refresh - Google Patents
Video coding method and apparatus with periodic refresh Download PDFInfo
- Publication number
- WO1998014011A1 WO1998014011A1 PCT/GB1997/002637 GB9702637W WO9814011A1 WO 1998014011 A1 WO1998014011 A1 WO 1998014011A1 GB 9702637 W GB9702637 W GB 9702637W WO 9814011 A1 WO9814011 A1 WO 9814011A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- segment
- data
- count
- picture
- encoding
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
- H04N19/103—Selection of coding mode or of prediction mode
- H04N19/107—Selection of coding mode or of prediction mode between spatial and temporal predictive coding, e.g. picture refresh
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
- H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding
Definitions
- the present invention relates to a method and apparatus for encoding data by predictive encoding and periodic refreshment of the data.
- a method of encoding data by predictive encoding and periodic refreshment of the data comprising; dividing the data into segments and predictively encoding or refreshing each segment individually depending upon the history of predictions which were used to encode the segment.
- apparatus for encoding data by predictive encoding and periodic refreshment of the data comprising means to divide the data into segments and means to predictively encode or refresh each segment individually depending on the history of predictions which were used to encode the segment.
- the data that emanates from the encoder is a bit-rate reduced data stream.
- the format of the data stream has been subject to standardization by a working group which is known as the Moving Picture Experts Group (MPEG).
- MPEG coding techniques include a compression algorithm based on discrete cosine transform (DCT), image segmentation where pictures are split into blocks of samples, motion estimation and compensation and predictive coding.
- DCT discrete cosine transform
- interframe compression calculates the differences between successive picture frames.
- the discrete cosine transformation is eventually carried out on blocks of picture elements, typically an array of 8 x 8 pixels.
- a digital encoder has two memories, A and B.
- the memories are arranged to store a count value for each macro block within a picture.
- the memories have means to pseudo-randomly initialise the count values to a value between 0 and a maximum value MAX.
- the motion vectors used to motion compensate each macro block are also used to address the count value in memory A associated with each macro block used to predict the current macro block. There may be up to 4 values which are accessed by the motion vectors.
- the addressed count values are passed to a detector 10 which selects the maximum count value.
- the maximum count value from the detector 10 is supplied to a threshold circuit 11 which sets a flag in the event that the maximum count value has reached the preset value MAX.
- the flag is passed as an input to an OR gate 12 which responds by providing an indication that the current macro block requires to be refreshed. Refreshing means 13 in the encoder ensure that the macro block is refreshed within the video coding process.
- Another input to the OR gate 12 is provided to enable other processes within the overall video coding process to force the refreshing of the current macro block as indicated by the block 17.
- the output from the OR gate 12 is supplied as a control signal to a multiplexer 14.
- the multiplexer 14 receives as one input an incremental count from an incremental adder 15.
- the incremental adder 15 takes the maximum count value selected by the detector 10 and increments the maximum value by one.
- the incremental count from the adder 15 is output from the multiplexer 14 if the current macro block does not require refreshing. This is indicated by the control output from the OR gate 12.
- the incremental count value is entered in the memory B in a storage position associated with the current macro block being coded.
- the multiplexer 14 Whenever the control signal supplied by the OR gate 12 indicates that the current macro block is to be refreshed, the multiplexer 14 is controlled to supply a value of zero from a reset block 16. The value zero is used to reset the count value for the current macro block in the memory B.
- the processing by the encoder continues until all the macro blocks in the current picture have been processed which implies that all the count values are either incremented by one in the memory B or reset to zero. Means are provided to transfer the updated count values in the memory B into the memory A so that the updated count values are available in time to process the macro blocks of the next picture. This process continues for each successive picture in the succession of pictures which are encoded by the encoder.
- the logic within the block 17 may include means such as a pseudo-random number generator to supply signals to the OR gate 12 which affect the timing at which the macro blocks are refreshed.
- the OR gate 12 may thus be forced to supply an output at time when the threshold circuit 11 does not detect a count equal or exceeding the value of MAX.
- means may be provided to block the output from the OR gate 12 so that refreshing of the current macro block is delayed.
- the associated count stored in the memory B exceeds the value MAX plus one in this case.
- equal numbers of macro blocks may be refreshed in each frame. This may reduce the latency caused by large fluctuations in data rate.
- the encoder described can encode a succession of pictures in which the encoded data is compressed by predictive encoding and wherein the total picture area is divided into several tessellating picture areas that cover the entire picture area to be coded. Each one of these picture areas is allocated a count. On each new coding pass of a picture the count is incremented by 1. Whenever this count exceeds a predetermined value the picture area in question is refreshed and the count reset to zero.
- the counters may be individually initialised to any value less than the maximum. The counters can be over-ridden and forced to the maximum, thus making the next or current coding pass refresh that picture area.
- picture areas may be predicted from other areas in other pictures and it is possible for a picture area to have been repeatedly predicted from other areas that have not been refreshed for a considerable time. This will cause the picture quality to deteriorate and also prevent a decoder from being able to start the decode process in a deterministic manner.
- the described technique prevents this problem. On each new coding pass of a picture the count allocated to a picture area is the maximum of any of the count values associated with any picture area used in its prediction. The resulting value is then incremented and if this count exceeds the predetermined value MAX the picture area in question is refreshed and the count reset to zero.
- This technique guarantees that all parts of the picture will be refreshed in MAX + 1 pictures thus permitting a decoder to correctly decode the signal from any point in time.
- the picture will not deteriorate over time as all picture areas are guaranteed to be refreshed every MAX + 1 coding passes. Distortions will not propagate through the video sequence due to the motion compensated incrementing of the counters. This technique avoids the need for a periodic refresh of the entire picture area.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002258505A CA2258505A1 (en) | 1996-09-27 | 1997-09-26 | Video coding method and apparatus with periodic refresh |
AU45618/97A AU4561897A (en) | 1996-09-27 | 1997-09-26 | Video coding method and apparatus with periodic refresh |
JP10515417A JP2001501396A (en) | 1996-09-27 | 1997-09-26 | Method and apparatus for encoding data |
EP97943959A EP0928543A1 (en) | 1996-09-27 | 1997-09-26 | Video coding method and apparatus with periodic refresh |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9620176A GB9620176D0 (en) | 1996-09-27 | 1996-09-27 | Method and apparatus for encoding data |
GB9620176.9 | 1996-09-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998014011A1 true WO1998014011A1 (en) | 1998-04-02 |
Family
ID=10800593
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1997/002637 WO1998014011A1 (en) | 1996-09-27 | 1997-09-26 | Video coding method and apparatus with periodic refresh |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0928543A1 (en) |
JP (1) | JP2001501396A (en) |
AU (1) | AU4561897A (en) |
CA (1) | CA2258505A1 (en) |
GB (1) | GB9620176D0 (en) |
WO (1) | WO1998014011A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090304077A1 (en) * | 2008-06-06 | 2009-12-10 | Apple Inc. | Refresh method and apparatus |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5441734B2 (en) | 2010-01-28 | 2014-03-12 | 株式会社メガチップス | Image encoding device |
JP5700728B2 (en) * | 2013-11-18 | 2015-04-15 | 株式会社メガチップス | Image encoding device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5057916A (en) * | 1990-11-16 | 1991-10-15 | General Instrument Corporation | Method and apparatus for refreshing motion compensated sequential video images |
EP0499088A2 (en) * | 1991-02-11 | 1992-08-19 | General Instrument Corporation Of Delaware | Method and apparatus for communicating compressed digital video signals using multiple processors |
JPH0837660A (en) * | 1994-07-21 | 1996-02-06 | Toshiba Corp | Picture compression-encoding device |
US5508743A (en) * | 1991-12-06 | 1996-04-16 | Canon Kabushiki Kaisha | Moving image signal coding apparatus and moving image signal coding control method |
WO1996014711A1 (en) * | 1994-11-03 | 1996-05-17 | Picturetel Corporation | Method and apparatus for visual communications in a scalable network environment |
-
1996
- 1996-09-27 GB GB9620176A patent/GB9620176D0/en active Pending
-
1997
- 1997-09-26 WO PCT/GB1997/002637 patent/WO1998014011A1/en not_active Application Discontinuation
- 1997-09-26 AU AU45618/97A patent/AU4561897A/en not_active Abandoned
- 1997-09-26 JP JP10515417A patent/JP2001501396A/en active Pending
- 1997-09-26 EP EP97943959A patent/EP0928543A1/en not_active Withdrawn
- 1997-09-26 CA CA002258505A patent/CA2258505A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5057916A (en) * | 1990-11-16 | 1991-10-15 | General Instrument Corporation | Method and apparatus for refreshing motion compensated sequential video images |
EP0499088A2 (en) * | 1991-02-11 | 1992-08-19 | General Instrument Corporation Of Delaware | Method and apparatus for communicating compressed digital video signals using multiple processors |
US5508743A (en) * | 1991-12-06 | 1996-04-16 | Canon Kabushiki Kaisha | Moving image signal coding apparatus and moving image signal coding control method |
JPH0837660A (en) * | 1994-07-21 | 1996-02-06 | Toshiba Corp | Picture compression-encoding device |
WO1996014711A1 (en) * | 1994-11-03 | 1996-05-17 | Picturetel Corporation | Method and apparatus for visual communications in a scalable network environment |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 096, no. 006 28 June 1996 (1996-06-28) * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090304077A1 (en) * | 2008-06-06 | 2009-12-10 | Apple Inc. | Refresh method and apparatus |
US8780986B2 (en) * | 2008-06-06 | 2014-07-15 | Apple Inc. | Refresh pixel group selection and coding adjustment |
Also Published As
Publication number | Publication date |
---|---|
JP2001501396A (en) | 2001-01-30 |
CA2258505A1 (en) | 1998-04-02 |
AU4561897A (en) | 1998-04-17 |
EP0928543A1 (en) | 1999-07-14 |
GB9620176D0 (en) | 1996-11-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5949490A (en) | Distributing video buffer rate control over a parallel compression architecture | |
KR0168458B1 (en) | Distorting deminishing method and apparatus | |
US6049629A (en) | Coding apparatus for coding image data using one of an interpicture coding method and an interpicture motion-compensated coding method | |
US5646687A (en) | Temporally-pipelined predictive encoder/decoder circuit and method | |
EP0821857B1 (en) | Video decoder apparatus using non-reference frame as an additional prediction source and method therefor | |
KR960006762B1 (en) | 2-dimensional data scanning selecting circuit for image coding | |
US5537215A (en) | Apparatus for processing band-compressed signals having inter-frame and intra-frame signals | |
EP0633699B1 (en) | Forced intra-frame coding method | |
KR20040033275A (en) | Video encoding method, video decoding method, video encoding apparatus, video decoding apparatus, video encoding program, and video decoding program | |
US6069919A (en) | Low-delay encoding methods of moving pictures | |
JPH10509569A (en) | Memory usage to decode and display video with 3: 2 pulldown | |
JPH09331533A (en) | Animation image coder | |
EP1280356A2 (en) | Apparatus and method for compressing multiplexed video signals | |
JP2010016467A (en) | Image encoding apparatus and method | |
US5748248A (en) | Real time motion vector processing of image data | |
KR100256859B1 (en) | Apparatus and method of coding/decoding moving picture and strange medium storing moving picture | |
JPH06225279A (en) | Coding/decoding methods and coding/decoding devices | |
EP0928543A1 (en) | Video coding method and apparatus with periodic refresh | |
KR100384102B1 (en) | Variable-length encoder | |
KR20020026189A (en) | Efficient video data access using fixed ratio compression | |
US5500676A (en) | Method of encoding and multiplexing picture signals and apparatus utilizing the same | |
KR100269548B1 (en) | Image decoding device and method | |
KR100269882B1 (en) | Image coding and decoding method and related apparatus | |
JPS62284535A (en) | Method and apparatus for encoding data by employing block list conversion | |
CA2166623C (en) | Coding image data |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG US UZ VN YU ZW AM AZ BY KG KZ MD RU TJ TM |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): GH KE LS MW SD SZ UG ZW AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 1997943959 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 333223 Country of ref document: NZ |
|
ENP | Entry into the national phase |
Ref document number: 2258505 Country of ref document: CA Ref country code: CA Ref document number: 2258505 Kind code of ref document: A Format of ref document f/p: F |
|
WWE | Wipo information: entry into national phase |
Ref document number: 09214612 Country of ref document: US |
|
ENP | Entry into the national phase |
Ref country code: JP Ref document number: 1998 515417 Kind code of ref document: A Format of ref document f/p: F |
|
WWP | Wipo information: published in national office |
Ref document number: 1997943959 Country of ref document: EP |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1997943959 Country of ref document: EP |