[FFmpeg-devel] Path for minor problems related to ffmpeg help text and x264 configuration
Fri Sep 26 17:38:33 CEST 2008
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
> This applies to all the above: I think !!(flag & FLAG) would be
> preferred to the ternary stuff. And regardless, are they actually
> needed? Or is this the cosmetic stuff you mention?
Of course If you don't use x264_param2string() the ternary stuff is
>>> + // x4->params.analyse.b_ssim = 0;
>>> + x4->params.analyse.b_psnr = avctx->flags & CODEC_FLAG_PSNR ?
>>> 1 : 0;
I am suggesting to add a SSIM flag parameter, else SSIM is enabled by
default. Is that a good idea? It should slightly reduce encoding time.
Francesco Cosoleto | http://cosoleto.free.fr
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