[FFmpeg-devel] [PATCH] mpeg2: remove idct randomisation

Måns Rullgård mans
Mon Jun 21 00:35:15 CEST 2010

Alexander Strange <astrange at ithinksw.com> writes:

> On Jun 20, 2010, at 3:21 PM, Mans Rullgard wrote:
>> Since the beginning of time, the MPEG2 decoder has XORed the LSB of
>> all block coeffs into the last one, probably to produce a random
>> dithering for masking DCT mismatch errors.  This patch removes this
>> randomisation.  As a side-effect, the value of block_last_index is
>> now correct.
> Mismatch control is part of the MPEG-2 spec.
> http://www.neuron2.net/library/mpeg2/iso13818-2.pdf 7.4.4

Thanks.  Forget the patch then.

M?ns Rullg?rd
mans at mansr.com

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