[Ffmpeg-devel] Livestreaming FLV with ffserver is buggy

Chris Dolan chris
Mon Jul 17 15:25:46 CEST 2006

On Jul 16, 2006, at 9:26 AM, Timon Reinhard wrote:

> streaming flv with ffserver doesn't work fine: The videostream plays
> quite exactly *half the speed* it should (and sometimes stops
> completely) in swf-based flv-players.

 From my (limited) experience hacking FLV, this sounds like the  
stream that's being served has broken audio.  The time reference for  
FLV seems to be driven by audio in Macromedia's player, so any glitch  
will affect playback.  I see below that you have specified an audio  
rate of 22 kHz.  Are you sure that's right?  DV is usually higher,  
and I don't see any resampling arguments in your ffmpeg cmdline.

Perhaps you could post a sample FLV and/or and URL for your streaming  

> I'm using a recent svn checkout (4 days ago). Surprisingly, piping
> ffmpeg's output (in flv-format) directly to a crappy self-written
> streaming server works fine. So I think there's something up with
> ffserver. ;)
> The bug described above occurs regardless of the settings in
> ffserver.conf, here are they anyway:
> <Stream test1.flv>
> Feed feed1.ffm
> Format flv
> VideoCodec flv
> AudioBitRate 24
> AudioChannels 1
> AudioSampleRate 22050
> VideoBitRate 64
> VideoBufferSize 500
> VideoFrameRate 25
> VideoSize 320x240
> VideoIntraOnly
> AudioCodec mp3
> VideoCodec flv
> Preroll 5
> </Stream>
> My ffmpeg commandlines:
>   Method 1 (DV): dvgrab --noavc --format raw - | ffmpeg -f dv -i -
> http://localhost:8090/feed1.ffm
>   Method 2 (V4L): ffmpeg http://localhost:8090/feed1.ffm
> Neither ffmpeg nor ffserver outputs any errors/warnings.
> Thanks for any help,
> Timon


Chris Dolan, Software Developer, http://www.chrisdolan.net/
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