[MPlayer-users] Deblocking B-frames

[Ville Saari]

When pp=hb/vb is used for mpeg[124] with B-frames, the result is a
flicker that is more annoying than the blocking was. Apparently it
adjusts the filtering strength based on quantizer only, which causes
the B-frames to be filtered harder.

This is obviously wrong. Although the B-frames have higher quantizers,
their artifacts are not stronger or if they are, then the video is badly
encoded. If I encode lavc mpeg4 with constant quantizer 2 for [IP]-frames
and 4 for B-frames, then the result is very well balanced between different
frame types (subjectively and by psnr).

I believe that the proper behaviour for pp would be either to apply
a vb_qfactor/vb_qoffset-like correction to B-frame quantizers or
just to ignore the quantizer for B-frames and use the one from the
last non-B-frame instead.

-- 
 Ville