The VideoLAN Forums

Trying to stream with BlackMagic Intensity Pro card under Ubuntu 11.10.

Using custom built vlc
VLC media player 1.2.0-git Twoflower (revision 1.1.0-pre1-6962-geb5b116)

started with following command line
everything works fine except growing delay of udp stream.
After several hours it delays about 30 mins. Have not waited more than 5-6 hours but suspect vlc will crash when there will be no memory for buffer.
There is no delay on FLV stream.

Constant delay is ok. How to eleminate growth?

Turn off multithreaded encoding, maybe,

You mean use threads=1 ?
It does not help - delay still grows and vlc memory usage too, while making quality of stream unacceptable.

This might be a bug in the transcoder or the muxer then.

changed vencoder to ffmpeg, dst to rtp.
The problem still there. I also have found that delay (and memory usage) starts growth after some time following vlc start.

Further discovery with -vvv option shows that problem starts when following messages appear on stderr
..
main input warning: clock gap, unexpected stream discontinuity
main input warning: feeding synchro with a new reference point trying to recover from clock gap
...

Oh that... The source has a discontinuity. This might be a bug in the decklink plugin, a hardware problem, or plain stupid scheduling jitter... I guess VLC attempts to recover from the problem in a way that causes extra buffering.

What is strange there is no delay growth with FLV1 http output.
And the problem starts after 35-45 minutes of streaming.
Now I've made workaround - just parsing stderr and restaring vlc on 'unexpected stream discontinuity'.