Method and system for generating block mode conversion table for efficient video transcoding
AssigneeEcole De Technologie Superieure
InventorsIsabelle Metoevi, Stéphane Coulombe
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Abstract
A method and system for generation of a block mode conversion table for use in online transcoding of a sequence of input images in a first format to a sequence of output images in a second format are described. The table is based on a sequence of training images and provides an effective mapping between the encoding block modes and respective candidate transcoding block modes used during the online transcoding. The method utilizes the encoding block mode, the motion vectors and the residual information extracted during the decoding of the training image to generate the block mode conversion table. A corresponding system is also provided.
Claims27
A computerized method for generating a block mode conversion table for selecting transcoding block modes required for transcoding a sequence of input images, each input image comprising one or more input macroblocks of pixels encoded in a first format into a sequence of output images, each output image comprising one or more output macroblocks of pixels encoded in a second format, the method comprising:
- (a1) providing training images, each training image comprising one or more training macroblocks of pixels encoded in the first format;
- (b1) transcoding each training macroblock (MB) into a transcoded training MB encoded in the second format by using a codec device;
- and
- (c1) generating the block mode conversion table containing multi-tuples, each multi-tuple having a first tuple, a second tuple, and a third tuple, each said first tuple including a first training block mode for a sub-set of the training MBs encoded using the first training block mode, each said second tuple including a class identifier for the training MBs, identifying those MBs in the sub-set, whose residual information satisfies a predetermined set of constraints, and each said third tuple including a list of second training block modes used by the codec device in transcoding those training macroblocks in the sub-set that have the class identifier indicated in the corresponding said second tuple.
A system for generating a block mode conversion table for selecting transcoding block modes for transcoding a sequence of input images, each input image comprising one or more input macroblocks of pixels encoded in a first format into a sequence of output images, each output image comprising one or more output macroblocks of pixels encoded in a second format, the system comprising:
- a processor, and a non-transitory computer readable storage medium having computer readable instructions stored thereon, for execution by the processor, forming:
- (a14) a training image repository providing training images, each training image comprising one or more training macroblocks of pixels encoded in the first format;
- (b14) a codec device transcoding each training macroblock (MB) into a transcoded training MB encoded in the second format;
- and
- (c14) a conversion table generator module generating the block mode conversion table containing multi-tuples, each multi-tuple having a first tuple, a second tuple, and a third tuple, each said first tuple including a first training block mode for a sub-set of the training MBs encoded using the first training block mode, each said second tuple including a class identifier for the training MBs, identifying those MBs in the sub-set, whose residual information satisfies a predetermined set of constraints, and each said third tuple including a list of second training block modes used by the codec device in transcoding those training macroblocks in the sub-set that have the class identifier indicated in the corresponding said second tuple.
A non-transitory computer readable storage medium, having a computer readable program code instructions stored thereon for execution by a processor, causing the processor to:
- (a1) retrieve training images, each training image comprising one or more training macroblocks of pixels encoded in the first format:
- (b1) transcode each training macroblock (MB) into a transcoded training MB encoded in the second format by using a codec device:
- and
- (c1) generate the block mode conversion table containing multi-tuples, each multi-tuple having a first tuple, a second tuple, and a third tuple, each said first tuple including a, first training block mode for a sub-set of the training MBs encoded using the first training block mode, each said second tuple including a class identifier for the training MBs, identifying those MBs in the sub-set, whose residual information satisfies a predetermined set of constraints, and each said third tuple including a list of second training block modes used by the codec device in transcoding those training macroblocks in the sub-set that have the class identifier indicated in the corresponding said second tuple.
Dependencies are inferred from the claim text.