mpegtsmux at high bitrates

[Edward Hervey]

I profiled mpegtsmux, there are indeed some issues. I opened a bug
regarding that.

 https://bugzilla.gnome.org/show_bug.cgi?id=709826

Note that it doesn't prevent using the other tricks I mentionned.

   Edward

On Thu, 2013-10-10 at 08:35 +0200, Edward Hervey wrote:
> Hi,
> 
> On Wed, 2013-10-09 at 09:22 -0700, cfadeley wrote:
> > That is what im seeing.  seems to me that exceeding 2.5-3mb/s using the
> > mpegtsmux causes a frame loss.
> > 
> > And i think what is happening is the mpegtsmux seems to only be able to
> > packetize at max rate of 2.5mb/s.  And i am assuming this is due to the way
> > it packetizes the items in such small sizes.  The amount of packets and
> > buffers that need to be produced is not optimal at all. 
> > 
> > So i have I-frames that come in at around 3-4mb/s where as my P-frames are
> > only around 1.5mb/s
> > 
> > So by the time the mpegtsmux processes the I-frame, a few p-frames are
> > getting dropped from the queue it grabs from.  
> 
>   Queues aren't leaky. Nothing is dropped in the pipeline. The only
> place where stuff can be dropped is .. over the network.
> 
> > 
> > Again this only happens if I produce data larger than 2-3mb/s.  
> > 
> > 
> > Does that make sense?  Seems like this tsmux isn't written well at all for
> > high bitrate in real time.
> 
>   Has someone profiled it ? The only thing one can state for sure is
> "The pipeline results in pushing out data in such a way that some of it
> gets lost over the network".
> 
>   Have you tried setting alignment=7 on mpegtsmux to ensure it pushes
> out buffers with 7 mpeg-ts packets which will fit nicely in a 1500 MTU
> udp packet ?
> 
>   Put queues before and after mpegtsmux to ensure it has a dedicated
> thread for muxing. It could also help.
> 
>   You are using latest mpegtsmux ?
> 
>      Edward
> 
> 
>     Edward
> 
> > 
> > 
> > 
> > --
> > View this message in context: http://gstreamer-devel.966125.n4.nabble.com/mpegtsmux-at-high-bitrates-tp4662473p4662484.html
> > Sent from the GStreamer-devel mailing list archive at Nabble.com.
> > _______________________________________________
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> 
> 
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-- 
Edward Hervey
bilboed at bilboed.com