Maybe I'm wrong, but, by reading the code of the media server, it
looks likes it relies on an average BR to determine when to send the
packets (based on past packets).
Yes. (This is done in "MPEG2TransportStreamFramer".)
The PCR is used to compute this average, but not to determine when
to actually send the packets. (I might be totally wrong here as I
must admit that the code is quite complex and I probably have missed
something.....).
Now, if I'm not totally wrong, would there be a way to either:
- Rely on PCR to determine when to send packets (something
like: get the next PCR, determine BR from first packet till this PCR
packet, send packets in a way where the packet containing the PCR is
sent on time).
The "MPEG2TransportStreamFramer" code is intended to work when
streaming arbitrary Transport Stream data - including Transport
Stream data that might come 'live' from an encoder. It therefore has
no knowledge of 'the next PCR' (because it doesn't look ahead in
time). However...
- Or: use the index file to store current frame BR (so use
the actual BR of a frame instead of an average based on past frames)
Yes, for Transport Stream files for which we have pre-computed an
index file, we do - in principle - have enough 'future' information
(using PCR values) from which we could compute a more accurate
'duration' for each outgoing Transport Stream packet. In the past I
had considered modifying "MPEG2TransportStreamFramer" to use this
information, but didn't (because such a solution would work only for
Transport Stream files for which we have index files, whereas the
existing code works for any Transport Stream data).
However, because - as you noted - excessively VBR streams are more
likely to be a problem with H.264 Transport Streams, I think I'll
take another look at this, to see if we can use the index file - when
present - to generate more accurate Transport Stream 'durations'.
--
Ross Finlayson
Live Networks, Inc.
http://www.live555.com/
_______________________________________________
live-devel mailing list
live-devel@lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
