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