[x264-devel] Is it possible to dynamically change the quality mode using libx264

[declan harrison]

On Mon, Oct 26, 2009 at 7:02 PM, Jason Garrett-Glaser <darkshikari at gmail.com
> wrote:

> On Mon, Oct 26, 2009 at 11:12 AM, declan harrison
> <harrison.declan at googlemail.com> wrote:
> > Hi
> >
> > Im using x264 with ffmpeg to encode videos on the fly (realtime with
> minimum
> > buffering) in a proxy.  So I am working on a HTTP stream and therefore 1
> > pass encoding is the only option available to me.
> >
> > My use case is that after encoding the video for say 10 seconds with a
> > "--crf" value of 22 another network element informs me that I need to
> > increase/decrease the quality of the video stream being sent to the
> client.
> > I then would like to change the effective "crf" value that I am currently
> > encoding the video stream.
>
> For streaming you need to set a maxrate and bufsize so that you don't
> exceed the bounds of your connection.  If you want absolutely no
> buffer whatsoever, i.e. zero-latency, you need to set bufsize =
> (maxrate / framerate).
>
> x264 currently does not support reconfiguring ratecontrol in realtime,
> but you can re-init the encoder if you want.
>
>
> Hi Jason

So re-init the encoder will this cause many issues for the client or do you
think that it will pass without much interference?

Do you know if similar functionality has been implemented/requested by any
of the users of x264 that you are aware of?  I would like to know of any
potoential pot-holes that might trip me up here.

Thanks
Declan
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