Page 1 of 1

Fast pulsing video effect

Posted: 29 Sep 2009 12:49
by paaland
Ok, a strange problem here. Using latest VLC (1.0.2) to record a live video stream to 2000 kbit/s mp4 using this command:

Code: Select all

VLC.exe -Idummy --run-time=30 udp://@239.1.1.11:1234 :sout=#transcode{vcodec=mp4v,vb=2000,scale=1,acodec=mp4a,ab=128,channels=2,deinterlace,audio-sync,samplerate=44100}:duplicate{dst=std{access=file,mux=mp4,dst=D:\\temp\\test_2000.mp4}} vlc://quit
Click to download the resulting test_2000.mp4 zipped (7 MB).

As you can see about every 0.5 seconds there is a very pixelated frame, it's especially viewable on the skin colours (forehead, neck). I've tried a combination of various bitrates and codec's (div3, mpg2 and mp4), and all have the same pulsating effect.

When playing back using Windows Media Player the pulse is still there, but much harder to see. Any ideas on how to get rid of this problem?

Re: Fast pulsing video effect

Posted: 29 Sep 2009 14:15
by VLC_help
mp4v encoder in VLC sucks. It used to be a bit better but at some point it got awful.

Re: Fast pulsing video effect

Posted: 29 Sep 2009 14:21
by paaland
mp4v encoder in VLC sucks. It used to be a bit better but at some point it got awful.
I get the same problem with mpg2 and avi (divx) as well.

vcodec mux
mpg2v ts
div3 avi
mpg4a mp4

All have the same pulsing problem, but it seems program dependant. In a single long recording that includes multiple tv-programs one program can be fine, while the next has the problem. Can it be related to interlacing or not etc? I think NRK is sending different quality/interlacing etc on old tv-reruns vs. feks the news.

Re: Fast pulsing video effect

Posted: 30 Sep 2009 12:53
by VLC_help
x264 is the only encoder that will produce good quality on low bitrates in VLC.