Method and device for transcoding video data from H.264 to H.265
AssigneeSagemcom Broadband SAS
InventorRoger Samy
Life of this patent
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Abstract
A device for transcoding a video data stream in the H.264 format into a video data stream in the H.265 format includes circuitry adapted for performing a merging of adjacent macroblocks of the data stream in the H.264 format according to a predetermined criterion of frequency similarity of the discrete cosine transform coefficients of said macroblocks after application of an inverse quantisation operation; and for determining motion vectors in the H.265 format on the basis of motion vectors in the H.264 format by performing, for the macroblocks resulting from the merging of macroblocks issuing from the data stream in the H.264 format, a combination of the motion vectors of said macroblocks issuing from the data stream in the H.264 format.
Claims16
A transcoding method for transcoding a video data stream in the H.264 format into a video data stream in the H.265 format, said method being implemented by a transcoding device comprising electronic circuitry adapted to execute the method, wherein said method comprises:
- receiving the data stream in the H.264 format;
- generating merged macroblocks by merging adjacent macroblocks issuing from the data stream in the H.264 format when a predetermined criterion of frequency similarity of the discrete cosine transform (DCT) coefficients of said adjacent macroblocks occurs after application of an inverse quantisation operation, the merging being performed in the DCT domain;
- determining new motion vectors in the H.265 format on the basis of motion vectors issuing from the data stream in H.264 format by performing, for the merged macroblocks, a combination of the motion vectors of said adjacent macroblocks issuing from the data stream in the H.264 format;
- and
- generating the data stream in the H.265 format on the basis of the merged macroblocks and the new motion vectors;
- wherein, for merging four of the adjacent macroblocks so as to form a resultant square macroblock, the transcoding device implements:
- a first butterfly diagram applied on the DCT coefficients after inverse quantization of two first adjacent macroblocks along the vertical dimension, thus enabling generating two first intermediate macroblocks from the two first of the adjacent macroblocks in the four adjacent macroblocks;
- a second butterfly diagram applied on the DCT coefficients after inverse quantization of two other adjacent macroblocks along the vertical dimension, thus enabling generating two second intermediate macroblocks from the other two of the adjacent macroblocks in the four adjacent macroblocks;
- and
- a third butterfly diagram applied on merged DCT coefficients of the intermediate macroblocks along the horizontal dimension, thus enabling generating the resultant square macroblock.
A transcoding device for transcoding a video data stream in the H.264 format into a video data stream in the H.265 format, wherein said transcoding device comprises electronic circuitry adapted for:
- receiving the data stream in the H.264 format;
- generating merged macroblocks by merging adjacent macroblocks issued from the data stream in the H.264 format when a predetermined criterion of frequency similarity of the discrete cosine transform (DCT) coefficients of said macroblocks occurs after application of an inverse quantisation operation, the merging being performed in the DCT domain;
- determining new motion vectors in the H.265 format on the basis of motion vectors issuing from the data stream in the H.264 format by performing, for the merged macroblocks, a combination of the motion vectors of said adjacent macroblocks issuing from the data stream in the H.264 format;
- and
- generating the data stream in the H.265 format on the basis of the merged macroblocks and of the new motion vectors;
- wherein, for merging four of the adjacent macroblocks so as to form a resultant square macroblock, the transcoding device implements:
- a first butterfly diagram applied on the DCT coefficients after inverse quantization of two first adjacent macroblocks along the vertical dimension, thus enabling generating two first intermediate macroblocks from the two first of the adjacent macroblocks in the four adjacent macroblocks;
- a second butterfly diagram applied on the DCT coefficients after inverse quantization of two other adjacent macroblocks along the vertical dimension, thus enabling generating two second intermediate macroblocks from the other two of the adjacent macroblocks in the four adjacent macroblocks;
- and
- a third butterfly diagram applied on merged DCT coefficients of the intermediate macroblocks along the horizontal dimension, thus enabling generating the resultant square macroblock.
A transcoding method for transcoding a video data stream in the H.264 format into a video data stream in the H.265 format, said method being implemented by a transcoding device comprising electronic circuitry adapted to execute the method, wherein said method comprises:
- receiving the data stream in the H.264 format;
- generating merged macroblocks by merging adjacent macroblocks issuing from the data stream in the H.264 format when a predetermined criterion of frequency similarity of the discrete cosine transform (DCT) coefficients of said adjacent macroblocks occurs after application of an inverse quantisation operation, the merging being performed in the DCT domain, wherein the predetermined criterion is when an information representative of the sum of the absolute differences between DCT coefficients, after inverse quantisation, of said adjacent macroblocks is below a first predefined threshold;
- determining new motion vectors in the H.265 format on the basis of motion vectors issuing from the data stream in H.264 format by performing, for the merged macroblocks, a combination of the motion vectors of said adjacent macroblocks issuing from the data stream in the H.264 format;
- and
- generating the data stream in the H.265 format on the basis of the merged macroblocks and the new motion vectors.
A transcoding device for transcoding a video data stream in the H.264 format into a video data stream in the H.265 format, wherein said transcoding device comprises electronic circuitry adapted for:
- receiving the data stream in the H.264 format;
- generating merged macroblocks by merging adjacent macroblocks issued from the data stream in the H.264 format when a predetermined criterion of frequency similarity of the discrete cosine transform (DCT) coefficients of said macroblocks occurs after application of an inverse quantisation operation, the merging being performed in the DCT domain, wherein the predetermined criterion is when an information representative of the sum of the absolute differences between DCT coefficients, after inverse quantisation, of said adjacent macroblocks is below a first predefined threshold;
- determining new motion vectors in the H.265 format on the basis of motion vectors issuing from the data stream in the H.264 format by performing, for the merged macroblocks, a combination of the motion vectors of said adjacent macroblocks issuing from the data stream in the H.264 format;
- and
- generating the data stream in the H.265 format on the basis of the merged macroblocks and of the new motion vectors.
Dependencies are inferred from the claim text.