[MPlayer-users] Lossless h264 Encoding
poirierg at gmail.com
Wed Oct 17 15:47:35 CEST 2007
On 10/17/07, Ognjen Bezanov <Ognjen at mailshack.com> wrote:
> I want to be able to encode to lossless h264 streams using
> mplayer/mencoder, but I have had no luck so far.
> I scoured the web and the mailing-lists and so far the only thing I have
> found is a thread (url:
> specifying that setting qp_constant=0 should give me lossless encoding.
> All well and good, except that when I try setting that option I get the
> following error:
> "Option x264encopts: Unknown suboption qp_constant"
> Has mplayer changed the x264 options for lossless compression?
Yes, but apparently you didn't even care to read curren't manpage
This selects the quantizer to use for P-frames. I- and B-frames
are offset from this value by ip_factor and pb_factor, respec-
tively. 20-40 is a useful range. Lower values result in better
fidelity, but higher bitrates. 0 is lossless. Note that quan-
tization in H.264 works differently from MPEG-1/2/4: H.264's
quantization parameter (QP) is on a logarithmic scale. The map-
ping is approximately H264QP = 12 + 6*log2(MPEGQP). For exam-
ple, MPEG at QP=2 is equivalent to H.264 at QP=18.
> How would
> I enable lossless h264 in mplayer now?
A soldier will fight long and hard for a bit of colored ribbon.
-- Napoleon Bonaparte
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