[Live-devel] issue with streaming ulaw from memory buffer

[Ross Finlayson]

>I'm writing some code to stream live audio in ulaw format over RTP
>multicast. I derived a class from framedSource class to read in the
>data from a memory buffer. An audio recorder thread feeds ulaw audio
>data to this buffer. In the derived class, I specified frame size @
>128 bytes, duration @ 16000 us and the presentation time, etc in the
>"doGetNextFrame" function. The network sink is an instance of
>"SimpleRTPSink". It seems to be straightforward. However, the audio
>was very broken when played back from VLC. Later I found that the
>output RTP packet has 1024 bytes payload and arriving interval for
>each  RTP packet is 128 ms. I intended to have a 16-ms arriving
>interval and 128-byte RTP payload (which is the audio recorder's
>output frame size). Does this make any sense and how should I do that?

Yes, the solution is to specify that your "SimpleRTPSink" object 
should pack no more than one input frame at a time into each outgoing 
RTP packet.  You can do this by setting the 
"allowMultipleFramesPerPacket" parameter in the 
"createNew::createNew()" call to False.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/