[FFmpeg-devel] [RFC][PATCH] ticks_per_frame / timebase

Ivan Schreter schreter
Thu Feb 26 18:56:28 CET 2009

Michael Niedermayer wrote:
> On Thu, Feb 26, 2009 at 04:40:51PM +0100, Reimar D?ffinger wrote:
>> I think you missed at least one place (though that might be broken as it
>> is anyways), the problem is libx264.c:
>>     x4->params.i_fps_num = avctx->time_base.den;
>>     x4->params.i_fps_den = avctx->time_base.num;
>> The problem here is that obviously libx264 uses this for its rate
>> control - which means after this change bitrate will be regularly off by a
>> factor of 2 for H.264->H.264 encodings.
> do you think that there will be a problem after this change or have you
> actually reproduced one created by this patch or the recent changes to
> svn?
> if you have a actual reproduceable test case iam interrested in the details
> of it
I just did an empirical test with recoding interlaced H.264 to smaller 
non-interlaced H.264. It works with your change (provided tb_unreliable 
returns 0 for H.264).

Obviously, we feed libx264 exactly what it expects...

I didn't look at bitrate, though, only at framerate.



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