[vlc-devel] Re: Possible UDP/RTP streaming bug

Jean-Paul Saman jean-paul.saman at planet.nl
Fri Apr 13 13:59:37 CEST 2007

Dugal Harris wrote:
> Jean-Paul Saman wrote:
>> Dugal Harris wrote:
>>> Hi
>>> I have a problem when trying stream high resolution video over UDP / 
>>> RTP.  The video is 1600x1200 MJPG and I am streaming in its source 
>>> MJPG format with no transcoding.  The client gives discontinuity and 
>>> packet loss messages (see attached log for an example).  The upper 
>>> part of the client video looks ok but the rest is green / garbage.
>>> If I take the same source video and transcode it before UDP/RTP 
>>> streaming or stream it over HTTP, in its source format, then 
>>> everything works fine.
>>> I see this behaviour with the most recent vlc code as well as older 
>>> versions (0.8.6a and 0.8.5).
>>> Is this a bug or am I doing something wrong?
>> This is not a bug. What you see is that the network is saturated when 
>> using MJPEG images of 1600x1200. The network drops UDP/RTP packets on 
>> the floor when it saturates.
>> The resolution is to lower the quality of the image by either using 
>> smaller sized images or transcoding to a lower bitrate.
>> Gtz,
>> Jean-Paul Saman.
> Thanks.  This seems unlikely though - the source MJPG video is about 
> 15Mbs which I am streaming over an idle 100Mbs network.  Another thing I 
> found, that suggests a bug, is when I stream over HTTP and encapsulate 
> with ASF, it works fine but if I stream over HTTP and encapsulate with 
> TS I get the same problems.  So it seems like it is a problem with TS 
> encapsulation and not UDP / RTP packet loss.
> Regards
> Dugal
well you sure lose packets and usually that is caused by the network. 
Although you only send us the logging from the client side. To rule out 
a problem on the vlc server side (eg: muxer) we need info about your 
exact commandline, os and vlc logging.

Jean-Paul Saman.

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