[x264-devel] Reconfiguring x264 aspect ratio in the middle of stream
jarmo.torvinen at jutel.fi
Mon Jan 12 15:14:15 CET 2009
> > I see some problems with this approach:
> > 1) it is too time consuming to call the x264_encoder_reconfig() just
> > the purpose of changing the aspect ratio, I'd rather have separate API
> > function which just would do that. But on the other hand, is there
> > enough justification to add another api call just for that purpose?
> x264_encoder_reconfig takes 7k cycles (2 microseconds), and you call it
> most once per GOP. I don't see the problem.
> > 3) according to initial tests, the aspect ratio changes, but the
> > is not always correct. This is because the aspect ratio info is sent
> > the SPS, so the timing depends on the timing of the scene cut. To have
> > correct timing, there should be some way to force a scenecut or
> > a SPS through the API when the aspect ratio changes.
> x264_picture_t->i_type = X264_TYPE_IDR
> What isn't guaranteed is that reconfig changes take place on the same
> frame they're input with, as opposed to whatever frame is encoded next.
Thanks for the tip. I tried to set that parameter but unfortunately it
seems that the
parameter is ignored in a call to x264_encoder_encode().
Maybe this comment in x264.h (struct x264_picture_t) is valid?
/* In: force picture type (if not auto) XXX: ignored for now
* Out: type of the picture encoded */
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