V4L capturing: Difference between revisions
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:*[http://developers.videolan.org/x264.html H264] -- a highly compressed codec optimized for streaming |
:*[http://developers.videolan.org/x264.html H264] -- a highly compressed codec optimized for streaming |
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:*[http://www.xvid.org xvid] -- free mpeg4 codec |
:*[http://www.xvid.org xvid] -- free mpeg4 codec |
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==Live x264 capture comparison== |
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The x264 encoder is now of such a high quality that it is possible to compress live tv on the fly with good results. So far I've been unable to find a solution that delivers on all counts: good audio/video synchronization, small file size, efficient encoding (full size and high quality without dropped frames), and a resulting file that streams with VLC. These results, however, may vary locally; the following is a status report from late March 2006 on a Debian amd64 sid with Marillat's multimedia packages. |
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<table border="10" cellpadding="5" width="70%" cellspacing="3" frame="hsides" rules="all"> |
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<tr> |
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<th>application</th> |
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<th>a/v sync</th> |
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<th>file size</th> |
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<th>efficiency</th> |
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<th>streaming</th> |
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</tr> |
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<tr> |
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<td></td> |
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<td></td> |
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<td></td> |
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<td></td> |
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<td></td> |
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</tr> |
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<tr> |
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<td>ffmpeg</td> |
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<td>?</td> |
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<td>small</td> |
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<td>good</td> |
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<td>yes</td> |
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</tr> |
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<tr> |
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<td>mencoder</td> |
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<td>great</td> |
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<td>small</td> |
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<td>poor</td> |
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<td>no</td> |
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</tr> |
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<tr> |
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<td>transcode</td> |
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<td>poor</td> |
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<td>large</td> |
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<td>great</td> |
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<td>yes</td> |
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</tr> |
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<tr> |
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<td></td> |
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<td></td> |
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<td></td> |
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<td></td> |
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<td></td> |
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</tr> |
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</table> |
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Revision as of 20:13, 27 March 2006
TV Recording applications
- DVR -- Digital Video Recorder for Linux
- ffmpeg
- fftv
- Freevo -- open-source digital video jukebox
- mencoder
- MythTV -- a Personal Video Recorder project
- streamer
- transcode
- videodog
Other frame grabbers
- See webcams
Common configuration and control commands
1. v4l2ucp -- universal control panel for v4l2 (available for Debian from Marillat)
2. Command-line control the TV card (v4lctl is a part of the xawtv package)
- v4lctl -c /dev/video0 list
- v4lctl -c /dev/video0 bright "60%"
- v4lctl -c /dev/video0 contrast "55%"
3. Capture the stream
- streamer (part of the xawtv package):
- Usage:
- streamer -i 1 -c /dev/video0 -s 320x240 -q -j 80 -f jpeg -n ntsc -b 24 -o /var/www/webcam.jpeg
- streamer -i 1 -c /dev/video0 -s 320x240 -q -j 80 -f jpeg -n ntsc -b 24 -o /dev/stdout |uuencode thief.jpeg|sendmail alarm@foo.com
- videodog:
- Usage:
- videodog -x 640 -y 480 -w 3 -b 1 -c 65535 -m PAL -q -d /dev/video0 -j -f /var/www/webcam.jpg
- mencoder
- webcam:
- This useful tool supports continuously moving (ftp or scp - ssh copy) of jpeg output to remote server. Also allows put in additional text (date time, location), rotating of image.
- Usage:
- webcam /etc/webcamrc
- See webcams for model and driver details
Compression formats
- Fourcc site
- H264 -- a highly compressed codec optimized for streaming
- xvid -- free mpeg4 codec
Live x264 capture comparison
The x264 encoder is now of such a high quality that it is possible to compress live tv on the fly with good results. So far I've been unable to find a solution that delivers on all counts: good audio/video synchronization, small file size, efficient encoding (full size and high quality without dropped frames), and a resulting file that streams with VLC. These results, however, may vary locally; the following is a status report from late March 2006 on a Debian amd64 sid with Marillat's multimedia packages.
| application | a/v sync | file size | efficiency | streaming |
|---|---|---|---|---|
| ffmpeg | ? | small | good | yes |
| mencoder | great | small | poor | no |
| transcode | poor | large | great | yes |