[FFmpeg-user] Recording logitech ultra vison,

[belcampo]

On 06/07/11 11:33, Sw at g wrote:
> Hi all,
>
> I am recording my Logitech Ultra Vison using ffmpeg with the following
> command,
>
> "ffmpeg -f video4linux2 -i /dev/video0 -s 640x480 -vcodec mpeg4 -sameq
> cam_`date +%F_%T`.mp4"
>
> However the video quality isn't as it's best, if I am using mencoder
> (which I understand isn't maintain any more) with x264 codec then the
> picture is much clearer and sharp (same size than ffmpeg)
>
> If I am trying to record the webcam with ffmpeg and libx264 (with the
> -vpre medium option) than the picture quality is the same as mpeg4 codec.
>
> So the question would be, how to have a sharper and clearer image the
> same as using mencoder (see below for the mencoder command line for
> reference)
>
> (mencoder tv:// -tv
> driver=v4l2:width=800:height=600:fps=15:device=/dev/video0 -ovc x264
> -nosound -o cam_`date +%F_%T`.avi)
To be able to say something meaningful, you should inspect your mencoder 
produced file with mediainfo. With mediainfo -f mencoder-produced.avi 
you get info like:
Encoding settings                : cabac=1 / ref=2 / deblock=1:0:0 / 
analyse=0x3:0x113 / me=umh / subme=4 / psy_rd=0.0:0.0 / mixed_ref=1 / 
me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / 
deadzone=21,11 / chroma_qp_offset=0 / threads=3 / nr=0 / decimate=1 / 
mbaff=0 / bframes=0 / keyint=250 / keyint_min=25 / scenecut=40(pre) / 
rc=abr / bitrate=1672 / ratetol=2.4 / qcomp=0.50 / qpmin=22 / qpmax=27 / 
qpstep=3 / ip_ratio=1.25 / aq=1:1.00
Then you know the default settings of mencoder, which can be replicated 
in ffmpeg. mencoder and ffmpeg use the same libx264 so if the settings 
are equal, the results will be equal.
>
> Also, I would very much like to be able to record the video with the
> time on the bottom corner it, is there such a command?
>
> Should you require any further details, please do not hesitate to
> contact me,
>
> Looking forward for your replies,
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