[FFmpeg-devel] Path for minor problems related to ffmpeg help text and x264 configuration

Jason Garrett-Glaser darkshikari
Fri Sep 26 17:42:30 CEST 2008

On Fri, Sep 26, 2008 at 8:38 AM, Francesco Cosoleto <cosoleto at gmail.com> wrote:
> 2008/9/25 Robert Swain <robert.swain at gmail.com>:
>  >>> +    /* char *res = (char *) x264_param2string(&x4->params, 0);
>  >>> +    av_log(avctx, AV_LOG_INFO, "Options: %s", res);
>  >>> +    x264_free(res); */
> [...]
>  > > Why libx264 doesn't already set all those values to 0 by default?
>  > Why is this commented code being added?
> That is only for debug purpose. However, I don't see a way for users to
> check libx264 parameters. Preset parameters in current release aren't
> checked, if you wrong writing "cfr" instead of "crf", "me" instead of
> "me_method", or also "i_qfactor=1.40" instead of "i_qfactor=0.71" you
> cannot see it. If I am not wrong libx264 writes setting used into H264
> stream (as returned by x264_param2string()), but FFmpeg strips these
> extra data. So, how to see these parameters before or after the file is
> processed?

Are you entirely sure?  I remember seeing a few rather awful x264
headers in fansubs and realizing they were due to ffmpeg's broken
defaults and the encoders' lack of knowledge thereof, so unless this
is a recent development I don't think its the case...

Dark Shikari

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