[Ffmpeg-devel] [PATCH] DV weights

Roman Shaposhnik Roman.Shaposhnick
Mon Feb 27 17:05:46 CET 2006

On Sat, Feb 25, 2006 at 02:41:33PM -0500, Dan Maas wrote:
> This patch implements AC coefficient weighing (per SMPTE 314M) for the
> DV encoder and decoder.
> I have also attached the Python script I used to make the tables.
> Weighing is implemented as fixed-point multiplication. I have chosen
> the number of bits of precision that gives the smallest error without
> causing 32-bit overflows. Weighing is inherently a lossy process
> because weighted coefficients have fewer bits than unweighted ones.
> But, in no case is the error greater than one least-significant bit.
> (the Python script checks this)
> Performance impact is less than 1%.

  Applied. With one minor nitpick -- next time, please include
  updated regression golden files as well.


More information about the ffmpeg-devel mailing list