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

[declan harrison]

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

> On Mon, Oct 26, 2009 at 12:22 PM, declan harrison
> <harrison.declan at googlemail.com> wrote:
> >
> >
> > 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?
>
> No issues for the client; the primary issue is that of tracking the
> VBV buffer fullness so that you can init the encoder with the correct
> initial occupancy for the VBV.
>

so if I re-init  the encoder will this ensure that all the meta data will
reflect the new video stream. Im thinking about NAL parameter sets etc?
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