[Libav-user] Encoding with no compression with OpenH264

Arthur Muller muller at vki.com
Tue Mar 8 18:44:54 CET 2016


> I posted a patch yesterday to fix that, see:
> http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/211120

Excellent news. Thanks!

>The only parameters used by FFmpeg/libavcodec which affect the quality are the bitrate and the max_bitrate. I don't know if it possible to use other parameters exposed by the openh264 API, if that's the case patches are welcome (TM). So in >order to increase the quality you simply increase the bitrate.

I think you and I arrived at the same conclusion - that's what I wrote in my follow-up message a few minutes ago: I may have been using too high a frame rate.

>You can have a look at the wrapper code libavcodec/libopenh264enc.c to see how FFmpeg uses the openh264 API.

This is useful. Thanks again. Hopefully, I won't need to go there. I reduced the frame rate from a default of 30 frames/second to 1 frame per second. After all, I only have 17 frames and it's a scientific presentation. The video now takes 17 seconds to go through, which is reasonable. At 30 frames per second everything was over in the blink of an eye, so the only way to make this happen was to reduce the quality.


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