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Adapt the size of RTP packets to the H.264 NALU size

Posted: 09 Mar 2009 18:45
by lukinus
Dear friends,

please accept my aplogy if I am writing in the wrong board.

I am trying to stream 264 files (encoded using the reference software JM) using VLC. When parsing the produced RTP packets, I noticed that they have a fixed size of 1344 Bytes.

I was wondering whether in VLC is implemented the possibility of:

1) Send a single NALU each RTP packet.
2) Adapt the size of the RTP payload to the size of the NALU size.

If I am writing in the wrong board, I would appreciate if you can redirect me to the right place!

Best Regards,

Luca

Re: Adapt the size of RTP packets to the H.264 NALU size

Posted: 09 Mar 2009 19:56
by Rémi Denis-Courmont
VLC sends one NAL per RTP packet, assuming that the MTU is large enough. Otherwise, it has no choice but to fragment.

If you don't want fragmentation, increase the RTP stream output MTU. Beware that increasing the MTU above what your network can do is a really bad idea.

Re: Adapt the size of RTP packets to the H.264 NALU size

Posted: 10 Mar 2009 19:27
by lukinus
Dear Remi,

thank you very much for your answer. Actually the size of my H.264 NALUs was limited to 750 bytes, therefore the size of the RTP packets is supposed to be limited to 762 bytes. Under this conditions, would you expect the RTP packets size limited to this value?

I encoded the sequence in the AnnexB format.

Thank you very much for your support,

Luca

Re: Adapt the size of RTP packets to the H.264 NALU size

Posted: 10 Mar 2009 22:09
by Rémi Denis-Courmont
This extends beyond my limited knowledge of the RTP AVC support.