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| author | lorenm <lorenm@b3059339-0415-0410-9bf9-f77b7e298cf2> | 2005-01-13 20:13:00 +0000 |
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| committer | lorenm <lorenm@b3059339-0415-0410-9bf9-f77b7e298cf2> | 2005-01-13 20:13:00 +0000 |
| commit | 884635915566affab252f1799be43fd99de292ea (patch) | |
| tree | 2a587a52879a00e230ccc5b150b0c42d3f98eef8 /DOCS | |
| parent | 875731cc527eed291ffac727b985cf9147033d6a (diff) | |
| download | mpv-884635915566affab252f1799be43fd99de292ea.tar.bz2 mpv-884635915566affab252f1799be43fd99de292ea.tar.xz | |
more on H.264's quantization parameter
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@14489 b3059339-0415-0410-9bf9-f77b7e298cf2
Diffstat (limited to 'DOCS')
| -rw-r--r-- | DOCS/man/en/mplayer.1 | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/DOCS/man/en/mplayer.1 b/DOCS/man/en/mplayer.1 index 630926856a..86c5f17fb9 100644 --- a/DOCS/man/en/mplayer.1 +++ b/DOCS/man/en/mplayer.1 @@ -7062,11 +7062,10 @@ This selects the quantizer to use for P-frames. I- and B-frames are offset from this value by ip_factor and pb_factor, respectively. 20\-40 is a useful range (default: 26). Lower values result in better fidelity, but higher bitrates. -Note that quantization in H.264 works differently from MPEG-1/2/4. +Note that quantization in H.264 works differently from MPEG-1/2/4: H.264's quantization parameter (QP) is on a logarithmic scale. -As an example, the bitrate difference between QP=20 and QP=40 -is about a factor of 10. -Useful quantizers in H.264 tend to be very large compared to MPEG-1/2/4. +The mapping is approximately H264QP = 12 + 6*log2(MPEGQP). +For example, MPEG at QP=2 is equivalent to H.264 at QP=18. . .TP .B pass=<1\-3> |