Re: [MEncoder-users] Cannot achieve better picture quality with MPEG2 - help needed

Nicolas Hesler wrote:
> I'm struggling to achieve better picture quality with mencoder and
> MPEG2, especially with video that contains gradients.
>
> I've uploaded a test example to ftp://upload.mplayerhq.hu/MPlayer/incoming/
>
> File : gradient.avi (an lossless FFV1 rgb32 video file used for encoding)
> File : screenshots_gradient.psd (a photoshop file containing screenshots
> to compare original to encoded screenshots)
>
> The PSD contains three labeled layers:
>
> - the first, the source, an uncompressed gradient
> - the second, a screenshot of the resulting MPEG-2 created with MEncoder
> (command line to follow)
> - the third, a screenshot of the resulting MPEG-2 created with Adobe
> Media Encoder.
>
> You'll notice that the Adobe Media Encoder screenshot has a much better
> picture (far less color distortion and far less banding) than the
> MEncoder screenshot.

This appears to be an effect of the colorspace conversion from BGRA to
YV12. -sws 8 appears to produce more even banding. You can try the
different scalers yourself. For example:

$ mplayer gradient.avi -vf scale=720:480,format=yv12 -sws 8

-Corey
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