[gst-devel] ffdec and QoS
wim.taymans at gmail.com
Wed Jun 10 10:33:07 CEST 2009
On Wed, 2009-06-10 at 10:15 +0200, Arnout Vandecappelle wrote:
> On Tuesday 09 June 2009 19:50:29 Wim Taymans wrote:
> > > The core of the problem, I think, is that the QoS handling doesn't take
> > > into account pipeline latency. It just assumes that throughput =
> > > 1/latency and doesn't seem to take into account that data can be buffered
> > > in the pipeline.
> > QoS does take latency into account (or else RTSP or RTP streams would
> > never play). It's probably that ffmpeg totally does not specify its
> > latency and thus it seems that buffers are simply arriving too late.
> > Adding a meaningful reply to the LATENCY query in ffmpeg will likely
> > solve this.
> Sounds good. How does ffmpeg know the latency, though? It buffers one
> frame, but since the framerate is unknown you can't convert this to time, can
The thing is that the latency query will be done when the sink prerolls,
which means that the decoder has at least decoded and pushed 1 buffer.
You could use the info you got from decoding this buffer to answer to
the latency query.
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