Re: Digital video recording software
On Wed, 25 Dec 2002 15:29:58 +0100 Russell Coker wrote:
> On Wed, 25 Dec 2002 14:49, Carlos Sousa wrote:
> > > don't know if it is packaged yet but there is actually a program
> > > on freshmeat.net called 'vcr' which is designed to make a computer
> > > act like a recorder.
(...)
> > I would however invest my efforts in the mplayer package (not
> > officially packaged). Its approaching final 0.90 release and is
> > apparently intended to handle all video needs under the sun :)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
only half-joking here, these guys do seem
bent on world domination...
>
> It appears that mencoder is only designed to convert from one format
> to another.
Haven't tried it myself (no hardware), but please see below.
> Last time I wanted to record something mencoder seemed unable to do it
> and I used vcr instead.
mplayer has been evolving very rapidly since I've been aware of it,
maybe you've tried an old version that couldn't do it yet.
> If I'm wrong then please give me a clue as to how I use mencoder to
> take input from a v4l device and write it to a DivX.
As I said, I haven't tried it, but from
http://www.mplayerhq.hu/DOCS/documentation.html :
2.5 TV input
This section is about how to enable watching/grabbing from V4L
compatible TV tuner. See the man page for a description of TV
options and keyboard controls.
(...)
A more sophisticated example. This makes MEncoder capture the full PAL
image, crop the margins, and deinterlace the picture using a linear
blend algorithm. Audio is compressed with a constant bitrate of 64kbps,
using LAME codec. This setup is suitable for capturing movies.
mencoder -tv on:driver=v4l:width=768:height=576 \
-ovc lavc -lavcopts vcodec=mpeg4:vbitrate=900 \
-oac mp3lame -lameopts cbr:br=64 \
-vop pp=lb,crop=720:544:24:16 -o output.avi
This will additionally rescale the image to 384x288 and compresses the
video with the bitrate of 350kbps in high quality mode. The vqmax option
looses the quantizer and allows the video compressor to actualy reach so
low bitrate even at the expense of the quality. This can be used for
capturing long TV series, where the video quality isn't so important.
mencoder -tv on:driver=v4l:width=768:height=576 \
-ovc lavc -lavcopts vcodec=mpeg4:vbitrate=350:vhq:vqmax=31:keyint=300 \
-oac mp3lame -lameopts cbr:br=48 \
-vop scale=384:288,pp=tn/lb,crop=720:540:24:18 -sws 1 -o output.avi
Both examples seem to take input from a v4l device and write output DivX
(mpeg4) video.
Sorry for the long mail, everyone.
--
Carlos Sousa
http://vbc.dyndns.org/
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