[Ffmpeg-devel] [PATCH 6/10] Remove "qdiff" OptionDef

Panagiotis Issaris takis.issaris
Wed Sep 20 13:37:40 CEST 2006


Op woensdag 20 september 2006 03:07, schreef Michael Niedermayer:
> > The attached patch removes the "qdiff" OptionDef. There was an
> > inconsistency in the range checking as zero was allowed but the range
> > reported did not allow zero. The patch assumes the range checking was
> > correct, but the message wasn't.
> a max of 31 is not enough for h.264
I'm not sure how to address this. The legal values for QP are [0,51] in H.264,
so I'd think a max of 51 would be enough.

But, if I look at how max_qdiff is being used, it seems it is used as qstep, 
which has values between 0.625 and 224.

takis at issaris:/usr/local/src/ffmpeg$ grep qdiff libavcodec/*264*
Binary file libavcodec/h264.o matches
libavcodec/x264.c:    x4->params.rc.i_qp_step = avctx->max_qdiff;

OT: qmin seems to be wrong for H.264 as it does not allow 0.

Should I split it in two different patches/commmits? One purely migrating the
qdiff range checking to the AVOption array, and one correcting the H.264 AVOption
limits (once I figure out what the correct max value for max_qdiff would be)?

With friendly regards,

More information about the ffmpeg-devel mailing list