[streaming] Re: using VLC as streaming server

[Frederic BECK]

> The diffrence betwen the first and the last way to stream is that in the first
> methode you use mp4 (video and audio) are encapsulate into a MPGE2 TS.
> With the second methode the mp4 is streamed as two separated stream.
> one for video and another one for audio. The same ip address will be used
> but on two different port ( as SDP describe).

I took a look at the packets sent on the network, the other difference i 
saw is taht with the method --sout '#standard...", the payload type is 
33 which means MPEG2TS and the data length is always 1328 bytes, whereas 
with the --sout '#rtp...' method, the payload type is 96 (private) and 
the data length is variable and the marker bit is used (a specific 
profile is used).

I tried then to open the demux context with RTP_PT_PRIVATE instead of 
RTP_PT_MPEG2TS, but then the decoding segfaults.

i made a few tests and here are the results :

1. with an avi file with a MPEG4 video stream created with ffmpeg, which 
is 213520 bytes long for 230 frames

#rtp -> 193041 bytes transfered, 216 frames decoded
#standard -> 235564 bytes transfered, 212 frames decoded

The resulting video has lots of grey parts in the pictures, as if only 
the transitions where presents, whereas the key frames are missing

2. with a mp4 file created with ffmpeg and mp4creator, which is 205713 
bytes long for 230 frames

#rtp -> 186881 bytes transfered, no frame decoded (seg fault from 
libavcodec)
#standard -> 228984 bytes transfered, 206 frames decoded

Has someone an idea or an explanation ?

thanks a lot
Fred

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