Apparatus for concealing errors in a digital video processing system

• US 5,455,629 A
• Filed: 02/12/1993
• Issued: 10/03/1995
• Est. Priority Date: 02/27/1991
• Status: Expired due to Term

• Current Assignee: RCA Thomson Licensing Corporation
• Original Assignee: RCA Thomson Licensing Corporation
• Inventors: Zdepski, Joel W., Sun, Huifang
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US08/017,455
• Time in Patent Office: 963 Days
• Field of Search: 358/136, 358/133, 358/135, 358/138, 371/31, 348/420, 348/402, 348/426, 348/466
• US Class Current: 375/240.27
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/37 with arrangements for assigning different transmission priorities to video input data or to video coded data
• CPC Class Codes: H04N 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/50 using predictive coding H04N19/61 takes precedence
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/895 in combination with error concealment
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 7/54 the signals being synchronous H04N21/23602, H04N21/23614, H04N21/2365, H04N21/2368, H04N21/4341, H04N21/4342, H04N21/4347, H04N21/4348 take precedence

Abstract

A digital video signal processing system includes apparatus for concealing errors which might occur in reproduced images due to image data lost during signal transmission. The system includes circuitry for detecting transmitted video data, generating error signals if errors are present in segments (transport blocks) of the received data, and excising segments having errors from the data stream. The received data is applied to a decoder/decompressor system which decodes and decompresses the transmitted video data according to a predetermined sequence and applies the decompressed video data to a memory (for subsequent display or recording, etc.). The decompressor is responsive to the error signals for altering the predetermined sequence.

Claims

1. In a television processing system for converting compressed data representing images into noncompressed data, said compressed data occurring in transport blocks including a plurality of macroblocks, each macroblock containing a plurality of blocks of data, said transport blocks being subject to errors and including codewords from which an indication of an error in a transport block may be determined, apparatus comprising:

a source of transmitted said compressed data;

a detector responsive to said codewords for detecting errors in respective said transport blocks;

circuitry responsive to determination of an error, in a transport block for eliminating said plurality of macroblocks contained in said transport block and replacing such eliminated plurality of macroblocks, at least in part, with predetermined sequences of data in compressed format, which sequences emulate, at least in part, compressed data representing a plurality of macroblocks corresponding to said eliminated plurality of macroblocks; and

a decompressor, having an input port coupled to said circuitry, and having an output port for providing decompressed data representing images.

2. The system set forth in claim 1 wherein said decompressor is responsive to said predetermined sequences of compressed data for providing substitute decompressed video signal information for decompressed video signal information corresponding to ones of said blocks of compressed data in macroblocks which were eliminated.

3. The system set forth in claim 1 wherein said circuitry further includes means for including motion vector, derived from neighboring macroblocks, with said predetermined sequences of data.

4. In a television processing system for converting compressed data representing images into noncompressed data, said compressed data occurring as blocks of data and being subject to errors, apparatus comprising:

means for receiving said compressed data and detecting errors therein, and responsive to said errors, replacing blocks of compressed data in which errors occurred with predetermined sequences of data in compressed format which sequences emulate, at least in part, the compressed data in which errors occurred;

decompressing means, having an input port coupled for receiving compressed data from said means for receiving, and having an output port for providing decompressed data;

a memory means coupled to receive decompressed video signal from said decompression means;

means associated with said means for receiving, for generating an error map representing image areas corresponding to one of said blocks which were replaced; and

means responsive to said error map for inhibiting said memory means from writing decompressed video data into memory locations corresponding to said ones of said blocks which were replaced.

5. In a television processing system for converting compressed data representing images into noncompressed data, said compressed data occurring as blocks of data and being subject to errors, apparatus comprising:

means for receiving said compressed data and detecting errors therein, and responsive to said errors, replacing blocks of compressed data in which errors occurred with predetermined sequences of data in compressed format which sequences emulate, at least in part, the compressed data in which errors occurred;

decompressing means, having an input port coupled for receiving compressed data from said means for receiving, and having an output port for providing decompressed data, said decompressing means being responsive to said predetermined sequences of compressed data for providing substitute decompressed video signal information corresponding to ones of said blocks of compressed data in which errors occurred; and

means responsive to user stimuli for replacing entire frames of compressed video data with substitute compressed video data in order to provide special effects.

6. In a video signal processing system for decompressing transmitted compressed video data, said compressed video data occurring in blocks and subject to incurring errors, apparatus for detecting the occurrence of errors and replacing blocks of compressed video data with predetermined sequences of compressed data emulating, in part, compressed video data;

decompression means for decompressing said compressed video data including said predetermined sequences; and

means associated with said apparatus for detecting errors and said decompression means for replacing decompressed video data corresponding to ones of blocks of compressed data in which errors occurred, with temporally delayed, spatially collocated decompressed video data.

7. Apparatus for decompressing video data provided in high and low priority channels, compressed video data having been formed in macroblocks each containing a plurality of blocks of data, the data in respective macroblocks and blocks being hierarchically layered, with data through hierarchy level K (a variable) for respective blocks being included in partial blocks of corresponding macroblocks which are arranged in high priority transport blocks in said high priority channel, and the remaining data below hierarchy level K in said respective blocks being included in partial blocks of corresponding macroblocks which are arranged in low priority transport blocks in said low priority channel, respective partial blocks of low priority data having an end of block code and respective partial blocks of high priority data not having an end of block code unless all data for a respective block is contained in the high priority block, and wherein said compressed video data is subject to incurring errors;

apparatus for concealing errors in images reproduced from said compressed video data comprising;

means responsive to compressed video data in said high and low priority channels for detecting the occurence of errors and excising transport blocks of information containing errors;

means for combining corresponding partial blocks of high and low priority information, and responsive to excised transport blocks of low priority information for appending end of block codes to corresponding partial blocks of high priority information; and

means for decompressing the combined blocks of information to produce a decompressed video signal.

8. The apparatus set forth in claim 7, wherein said means for combining include means for excising partial blocks in the low priority channel corresponding to excised partial blocks in the high priority channel.

9. The apparatus set forth in claim 8 wherein said means for combining further includes:

storage means for storing predetermined sequences of compressed data in compressed video format; and

means for replacing excised high priority macroblocks and corresponding excised low priority macroblocks with macroblocks of predetermined sequences of compressed data.

10. The apparatus set forth in claim 7 wherein said means for combining further includes:

storage means for storing predetermined sequences of compressed data in compressed video format; and

means for replacing excised high priority macroblocks and corresponding low priority macroblocks with macroblocks of predetermined sequences of compressed data.

11. The apparatus set forth in claim 7 wherein said transport blocks include indicia for identifying at least portions of the information contained in said transport blocks, and said apparatus further includes:

means for separating said indicia from respective transport blocks of information;

means for storing compressed video data from said high priority channel;

storage means for storing predetermined sequences of compressed data in compressed video format; and

wherein said combining means includes means responsive to said indicia for replacing excised high priority macroblocks and corresponding low priority macroblocks with macroblocks of said predetermined sequences of compressed data augmented with compressed video data from said means for storing compressed video data.

12. Apparatus for decompressing video data provided in high and low priority channels, compressed video data in said high priority channel arranged in transport blocks containing partial blocks of high priority data, and video data in said low priority channel arranged in transport blocks containing corresponding partial blocks of low priority data, and wherein said compressed video data is subject to incurring errors:

apparatus for concealing errors in images reproduced from said compressed video data comprising;

means responsive to compressed video data in said high and low priority channels for detecting the occurrence of errors and excising transport blocks of information containing errors;

means for combining corresponding partial blocks of high and low priority information, and responsive to excised transport blocks of low priority information for appending end of block codes to corresponding partial blocks of high priority information; and

means for decompressing the combined blocks of information to produce a decompressed video signal;

memory means coupled to said decompressing means for storing decompressed video signal in raster scan format, said memory being regularly updated with decompressed data from said decompressing means;

means associated with said means for detecting for generating an error map corresponding to image areas represented by compressed video data in ones of transport blocks which have been excised; and

means, responsive to said error map, for inhibiting said memory means from updating data in said memory means corresponding to image areas represented by compressed video data in said ones of transport blocks.