[Ffmpeg-devel] Could not find video grab device

Martin van Es mrvanes
Wed Aug 31 10:42:17 CEST 2005


Hi,

I might have done wrong starting my last post of with a big 'Hurray',
cause I don't seem to get any response to this problem anymore...
oops.

I am able to get some grablike activity from my camera with ffmpeg,
but (as you can read below) I'm still not able to grab (from the same
camera) for an asf stream?

Is there anybody that could give me a hint why ffpmpeg quits by
telling me it can't find the video grab device in this setup?

Grtz.
Martin

On 8/26/05, Martin van Es <mrvanes at gmail.com> wrote:
> Hurray, I got ffmpeg to grab some stuff, so it's probably my
> ffserver.conf and/or commandline that gets in the way:
> 
> The commandline I use is:
> ffmpeg -vd /dev/video0 -ad /dev/dsp1 http://host:8090/webcam.ffm
> 
> On 'host' I have ffserver running with this configuration:
> 
> Port 8090
> BindAddress 0.0.0.0
> MaxClients 10
> MaxBandwidth 1000
> CustomLog -
> 
> # Suppress that if you want to launch ffserver as a daemon
> NoDaemon
> 
> <Feed webcam.ffm>
> File /tmp/webcam.ffm
> FileMaxSize 512K
> 
> # Only allow connections from localhost to the feed
> #ACL allow 127.0.0.1
> </Feed>
> 
> # ASF compatible
> 
> <Stream webcam.asf>
> Feed webcam.ffm
> Format asf
> VideoFrameRate 10
> VideoSize cif
> VideoBitRate 128
> VideoGopSize 30
> VideoCodec msmpeg4v2
> #VideoBufferSize 40
> AudioCodec mp3
> AudioBitRate 32
> AudioChannels 1
> #NoAudio
> VideoHighQuality
> StartSendOnKey
> </Stream>
> 
> 
> This is the output I get (all local testing on 1 machine).
> first ffserver:
> minivanes:/usr/src/media/streaming/ffmpeg# ./ffserver
> ffserver started.
> 127.0.0.1 - - [Fri Aug 26 19:50:37 2005] "GET /webcam.ffm HTTP/1.0" 200 4165
> 127.0.0.1 - - [Fri Aug 26 19:50:37 2005] "GET /webcam.ffm HTTP/1.0" 200 4165
> 127.0.0.1 - - [Fri Aug 26 19:50:38 2005] "POST /webcam.ffm HTTP/1.0" 200 0
> 
> Then in another console ffmpeg:
> minivanes:/usr/src/media/streaming/ffmpeg# ./ffmpeg -vd /dev/video0
> -ad /dev/dsp1 http://localhost:8090/webcam.ffm
> ffmpeg version CVS, build 3211266, Copyright (c) 2000-2004 Fabrice Bellard
>   configuration:  --prefix=/usr --enable-mp3lame
>   built on Aug 26 2005 19:49:58, gcc: 4.0.1 (Debian 4.0.1-2)
> Could not find video grab device
> 
> What am I overlooking or what option changed from 4.8.0 so that this
> results in a 'Could not find video grab device' for what that's worth?
> 
> Martin
> 


-- 
if but was any useful, it would be a logic operator





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