Thread: Taking a screencast on N900
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divan is offline divan
2011-07-10 , 12:03
Posts: 100 | Thanked: 543 times | Joined on Jun 2010 @ Kiev, Ukraine
#26
So, there are three ways to do screencast on N900:
1) x11vnc method
Connect to N900 via vnc and grab video with x11grab/ffmpeg or vncrec.
On N900:
Code:
x11vnc
On desktop PC:
Code:
echo "Please, select window with vncviewer opened"
WINGEOM=$(xwininfo | grep geometry | tr ' ' '+')
OFFSET=$(echo $WINGEOM | cut -d'+' -f5,6 | tr '+' ',' | sed 's:^:+:')
ffmpeg -f x11grab -r 15 -s 800x480 -i :0.0$OFFSET -vcodec libx264 -vpre lossless_ultrafast -threads 0 -y n900_screencast_$(date +%H_%M_%S).mkv
Pros: perfect quality, unlimited recording time
Cons: low fps (9-10 max), no sound
Example: http://www.youtube.com/watch?v=nL-7CBwoHnE


2) ffmpeg with x11grab module recording
Record directly on the phone. It's something like:
Code:
$ ffmpeg -f x11grab -s 800x480 -r 24 -b 100k -bf 2 -g 300 -i :0.0 -ar 22050 -ab 64k -acodec libmp3lame outputvid.mpeg
Note, it's not the best parameters for ffmpeg, and you can tune it up.
But anyway it's slowest method.
Pros: very good quality, sound recording
Cons: low fps(5-8), limited recording time(by disk space), high CPU consumption

3) using tv-out and tv-tuner card
The best methond I've tested so far.
Tested with AverMedia TV pcmcia-tuner. On the desktop PC:
HTML Code:
cvlc v4l2:///dev/video1 :v4l2-standard=0 :v4l2-input=1 :input-slave=alsa://plughw:2,0 --sout='#transcode{vcodec=mp2v,vb=4096,acodec=mp2a,ab=192,scale=1,channels=2,deinterlace,audio-sync}:duplicate{dst=display,dst=std{access=file, mux=ps,dst="out.mpg"}}'
Then crop it with you favourite tool (Handbrake or mencoder for example).
Pros: relatively good quality, perfect fps rate (30fps), unlimited recording time, sound recording, no CPU consumption on N900
Cons: image quality isn't perfect
Example: http://www.youtube.com/watch?v=meTeTCSuCcc
 

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