Video processing system also compressing coding decision data
AssigneeBritish Broadcasting Corporation
InventorsPeter John Brightwell, Nicholas Dominic Wells, Phillip Nicholas Tudor
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Abstract
An MPEG2 decoded video signal is accompanied by a representation of the coding decisions to aid downstream re-encoding. The representation is MPEG compliant bit modified to reduce the number of bits.
Claims17
A video compression system comprising:
- an input for receiving a compressed bitstream which has been compressed in accordance with first compression coding decisions;
- a compression decoder operating on the received compressed bitstream to provide a decompressed video signal;
- means for extracting the first compression coding decisions from the compressed bitstream and generating therefrom an information signal representing the first compression coding decisions;
- coding decision modifying means for modifying the first compression coding decisions represented in the information signal such that the information signal representing such modified compression coding decisions has a reduced bit rate as compared with the information signal representing the first compression coding decisions;
- and
- a downstream compression encoder arranged to receive the decompressed video signal through a video channel and the information signal through an information channel and to re-encode the decompressed video signal utilizing the information signal representing the modified compression coding decisions to reduce quality loss in the cascaded decoding and re-encoding processes.
A video compression system comprising:
- an input for receiving a video signal with an embedded information signal representing first compression coding decisions;
- means for extracting the first compression coding decisions from the video signal and generating therefrom an information signal representing the first compression coding decisions;
- coding decision modifying means for modifying the first compression coding decisions represented in the information signal such that the information signal representing such modified compression coding decisions has a reduced bit rate as compared with the information signal representing the first compression coding decisions;
- and
- a downstream compression encoder arranged to receive the video signal through a video channel and the information signal through an information channel and to re-encode the decompressed video signal utilizing the information signal representing the modified compression coding decisions to reduce quality loss in the cascaded decoding and re-encoding processes.
A video compression system in which an encoder operates on a video signal in a compression encoding process using coding decisions having motion vectors to generate an encoded signal, and in which a decoder operates on the encoded signal in a compression decoding process to generate a decoded signal, wherein a representation of the coding decisions accompanies the decoded signal for use in a later signal process, wherein the coding decisions are modified to enable the coding decisions to be represented at a reduced bit rate, wherein a representation of the modified coding decisions accompanies the decoded signal, and wherein the modification of the coding decisions includes modification of at least one of the motion vectors.
A video compression system in which an encoder operates on a video signal in a compression encoding process using coding decisions to generate an encoded signal, and in which a decoder operates on the encoded signal in a compression decoding process to generate a decoded signal, wherein a representation of coding decisions accompanies the decoded signal for use in a later signal process, wherein the coding decisions are modified to enable them to be represented at a reduced bit rate, wherein the modified coding decisions are variable length coded and then buffered, wherein information about a level of the buffer is used to control the modification process, and wherein a representation of the modified coding decisions accompanying the decoded signal.
A method of performing cascaded decoding and re-encoding processes, the method comprising:
- providing a compressed bitstream which has been compressed in accordance with first compression coding decisions;
- decoding the compressed bitstream to generate a decompressed video signal;
- transferring the decompressed video signal to a downstream compression encoder through a video channel;
- extracting the first compression coding decisions from the compressed bitstream to generate an information signal, the information signal representing the first compression coding decisions;
- modifying the information signal such that the information signal represents modified compression coding decisions, the information signal representing the modified compression coding decisions having a reduced bit rate as compared with the information signal representing the first compression coding decisions;
- transferring the information signal to the downstream compression encoder through an information channel;
- and
- re-encoding the decompressed video signal using the information signal representing the modified compression coding decisions to reduce quality loss in the cascaded decoding and re-encoding processes.
A video compression system comprising:
- a decoder operable to receive a compressed bitstream which has been compressed in accordance with first compression coding decisions, to provide a decompressed video signal, to extract the first compression coding decisions from the compressed bitstream, and to generate an information signal representing the first compression coding decisions;
- a coding decision modifier operable to modify the first compression coding decision represented in the information such that the information signal representing such modified compression coding decisions has a reduced bit rate as compared with the information signal representing the first compression coding decisions;
- and
- a downstream encoder operable to receive the decompressed video signal through a video channel, to receive the information signal through an information channel, and to re-encode the decompressed video signal utilizing the information signal representing the modified compression coding decisions to reduce quality loss in the cascaded decoding and re-encoding processes.
Dependencies are inferred from the claim text.