Macroblock-based dual-pass coding method
OwnerFranck Hiron, Yannick Olivier +1inventors
InventorsFranck Hiron, Yannick Olivier, Philippe Guillotel
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Abstract
The method comprises the following steps: during the first pass, a memorization of the M best coding modes and their coding parameters per image macroblock, during the second pass, a calculation, according to the new quantization step determined by the regulating algorithm according to the parameters memorized, among the M coding modes memorized, of the coding mode minimising the bitrate-distortion criterion, to select it, a coding according to the selected coding mode. The applications relate to the compression of data.
Claims8
Dual pass coding method for a video image sequence, the coding being carried out per image macroblock according to the MPEG standard, a regulating algorithm regulating the bitrate by modification of a quantization step of transform coefficients of an image block, the first pass carrying out the calculation of the best coding modes, for a quantization step calculated by a first pass regulating algorithm, while minimising a bitrate-distortion criterion, characterized in that it comprises the following steps:
- during the first pass, a memorization of the M best coding modes and their coding parameters per image macroblock,
- during the second pass, a calculation, according to the new quantization step determined by the regulating algorithm according to the parameters memorized, among the M coding modes memorized, of the coding mode minimising the bitrate-distortion criterion, to select it,
- a coding according to the selected coding mode.
Dependencies are inferred from the claim text.