[FFmpeg-user] ffmpeg-10 audio and video sync problem.

Ly Tran Cong lytc at vega.com.vn
Tue Feb 7 06:47:16 CET 2012

Hi all,

I use this command to transcode multicast video to DarwinStreaming.

ffmpeg -i udp://
<>-an -c:v libx264 -profile baseline
-preset ultrafast -r 25 -s 320x240 -b:v
128k -coder 0 -refs 3 -bf 0 -g 150 -keyint_min 20 -qmin 10 -qmax 51 -qdiff
4 -trellis 0 -flags +global_header -vsync 1 -copyts -f rtp rtp:// -flags +global_header -vn -c:a libfaac -ar 22050 -b:a 8k
-ac 2 -vn -async 22050 -rtpflags +latm -fflags +latm -copyts -f rtp rtp://

then I use vlc to play that stream but I have to refresh vlc many time.
Sometime I can hear audio, sometime I can watch video without audio and
sometime I can watch video faster than audio.

Please let me know is there any problem with my command or ffmpeg sync


Tran Ly

Vega Corporation
98 Hoang Quoc Viet Str, Hanoi, Vietnam
Tel: 84 4 755 4190
Fax: 84 4 755 4190
Mobile: 84 91 487 1115
www.vega.com.vn; www.clip.vn; www.chacha.vn; www.ringring.vn

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