[vlc-devel] Playing H.264 RTP Stream without waiting to I Frame

Yedidia Amit amit.yedidia at elbitsystems.com
Thu Apr 2 11:01:28 CEST 2009



Hi All,
In short: 
Does VLC supports start playing H.264 RTP stream without receiving I/IDR
farmes? (I don't care abouth the expected artifacts)
 - SPS and PPS are sent both inband (RTP) and out of band (SDP).
Form tryout I know the the ffmepg decoder is able to play such
bitstream, however I suspect that the packetizer is dropping all packets
until the IDR frame. Is that correct?
In long: 
I have hardware encoder which sends h264/RFC3984 stream in multicast or
unicast. 
This hardware is also controlled by RTSP server (based on LIVE555). 
I want to be able to play the stream using VLC, and join the stream even
after the playback starte.
The problem is that the source generate only one IDR frame in the start,
and uses AIR (adaptive intra refresh) - to preserve a constant bitrate
as much aspossible. 
There are no other IDR or other I frames beside the first one. 
The RTSP server sends the SPS/PPS in the SDP, and they are also
transmitted in-band (RTP) from time to time. 
The first player which address the RTSP server and actually initiate the
stream (and receive the first IDR frame) is able to play the stream.
The second player which address the RTSP server and want to join the
same existing stream (and already missed the first IDR) is NOT able to
play the stream. 
I have no problem with the artifact I expect to see when starting to
decode withot proper refernce frame, since in short interval all
macroblocks will be refreshed (AIR).
Is such scenario is supported in VLC ?
If so what can be my problem? Are there other implementation that can
solve my probelm? . 

Regards,



Regards,


Amit Yedidia
Elbit System Ltd.

Email: amit.yedidia at elbitsystems.com
Tel: 972-4-8318905
----------------------------------------------------------



The information in this e-mail transmission contains proprietary and business 
sensitive information.  Unauthorized interception of this e-mail may constitute 
a violation of law. If you are not the intended recipient, you are hereby 
notified that any review, dissemination, distribution or duplication of this 
communication is strictly prohibited. You are also asked to contact the sender 
by reply email and immediately destroy all copies of the original message.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.videolan.org/pipermail/vlc-devel/attachments/20090402/0b1ebc41/attachment.html>


More information about the vlc-devel mailing list