mpegtsmux at high bitrates

[Edward Hervey]

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

> 
> 
> 
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