Difference between revisions of "V4L TV Viewing"

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m (Common configuration and control commands: moved Debian info to v4l2ucp article)
 
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There is a large number of applications for watching tv; here are a few:
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The following provides commands for adjusting common configuration settings for a [[What is V4L or DVB?|V4L device]]; which are useful for, say, enhancing the end user's experience while watching analogue TV or webcam viewing.
  
* [[xawtv]]
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==Common configuration and control commands==
* [[motv]]
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1. [[v4l2ucp]] -- universal control panel for v4l2 devices
* [[tvtime]]
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* [[zapping]]
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2. Command-line control the V4L device
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:a. v4lctl (part of the [[Xawtv#Associated_Utilities|xawtv package]])
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:* v4lctl -c /dev/video1 list
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:* v4lctl setnorm ntsc-m
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:* v4lctl setfreqtab us-cable
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:* v4lctl setfreqtab us-bcast
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:* v4lctl setchannel 3
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:* v4lctl volume mute off
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:* v4lctl volume 100
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:* v4lctl audio stereo
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:* v4lctl -c /dev/video0 setattr 'chroma agc' on (bttv only)
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:* v4lctl -c /dev/video0 hue "100%"  (or "0%" -- same thing)
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:* v4lctl -c /dev/video1 bright "50%"
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:* v4lctl -c /dev/video2 contrast "45%"
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:* v4lctl -c /dev/video0 color "50%"
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:b. [http://www.vanheusden.com/dov4l2/ dov4l2]
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:* Console tool that sets the parameters of a Video4Linux-device
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:* You can set picture size, brightness, contrast, tuner frequency, and so on.
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:* You can also retrieve a complete list of all current settings.
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==Test the video==
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3. Test the video
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:* xawtv -hwscan
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:* xawtv -remote -noxv -c /dev/video0 -vbidev /dev/vbi0
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4. Test overlay mode (capture card controls display -- easy on CPU)
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:* xawtv -noxv -capture overlay
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:* xawtv -v4l1 -capture overlay
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:* xawtv -xvtv -capture overlay
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:* xawtv -xvtv_overlay on -capture overlay
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:* xawtv -xvtv_overlay off -capture overlay
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5. Test grabdisplay mode (application controls display -- required for deinterlacing and other effects)
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:* xawtv -noxv -capture grabdisplay
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:* xawtv -v4l1 -capture grabdisplay
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:* xawtv -xvtv -capture grabdisplay
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:* xawtv -xvtv_overlay on -capture grabdisplay
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:* xawtv -xvtv_overlay off -capture grabdisplay
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6. Test streamer
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:* streamer -i "S-Video Input"
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7. Determine the characteristics of a recorded video file
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:* mplayer -vo dummy -identify <filename> 2>&1 | grep -E "VIDEO:|AUDIO:"
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You can put this into a script and for instance call it reveal:
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mplayer -vo dummy -identify $1 2>&1 | grep -E "VIDEO:|AUDIO:"
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Now you can issue "reveal <filename>" and see something like this:
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VIDEO:  [h264] 576x432  24bpp  29.970 fps  495.5 kbps (60.5 kbyte/s)
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AUDIO: 32000 Hz, 2 ch, s16le, 64.0 kbit/6.25% (ratio: 8000->128000)
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This command also gives you details:
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:* tcprobe -i <filename>
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However, at this point (transcode 1.0.2) it doesn't show you video bitrates.
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[[Category:Software]]
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[[Category:Apps & Utilities]]

Latest revision as of 03:37, 1 October 2011

The following provides commands for adjusting common configuration settings for a V4L device; which are useful for, say, enhancing the end user's experience while watching analogue TV or webcam viewing.

Common configuration and control commands

1. v4l2ucp -- universal control panel for v4l2 devices

2. Command-line control the V4L device

a. v4lctl (part of the xawtv package)
  • v4lctl -c /dev/video1 list
  • v4lctl setnorm ntsc-m
  • v4lctl setfreqtab us-cable
  • v4lctl setfreqtab us-bcast
  • v4lctl setchannel 3
  • v4lctl volume mute off
  • v4lctl volume 100
  • v4lctl audio stereo
  • v4lctl -c /dev/video0 setattr 'chroma agc' on (bttv only)
  • v4lctl -c /dev/video0 hue "100%" (or "0%" -- same thing)
  • v4lctl -c /dev/video1 bright "50%"
  • v4lctl -c /dev/video2 contrast "45%"
  • v4lctl -c /dev/video0 color "50%"
b. dov4l2
  • Console tool that sets the parameters of a Video4Linux-device
  • You can set picture size, brightness, contrast, tuner frequency, and so on.
  • You can also retrieve a complete list of all current settings.

Test the video

3. Test the video

  • xawtv -hwscan
  • xawtv -remote -noxv -c /dev/video0 -vbidev /dev/vbi0

4. Test overlay mode (capture card controls display -- easy on CPU)

  • xawtv -noxv -capture overlay
  • xawtv -v4l1 -capture overlay
  • xawtv -xvtv -capture overlay
  • xawtv -xvtv_overlay on -capture overlay
  • xawtv -xvtv_overlay off -capture overlay

5. Test grabdisplay mode (application controls display -- required for deinterlacing and other effects)

  • xawtv -noxv -capture grabdisplay
  • xawtv -v4l1 -capture grabdisplay
  • xawtv -xvtv -capture grabdisplay
  • xawtv -xvtv_overlay on -capture grabdisplay
  • xawtv -xvtv_overlay off -capture grabdisplay

6. Test streamer

  • streamer -i "S-Video Input"

7. Determine the characteristics of a recorded video file

  • mplayer -vo dummy -identify <filename> 2>&1 | grep -E "VIDEO:|AUDIO:"

You can put this into a script and for instance call it reveal:

mplayer -vo dummy -identify $1 2>&1 | grep -E "VIDEO:|AUDIO:"

Now you can issue "reveal <filename>" and see something like this:

VIDEO:  [h264]  576x432  24bpp  29.970 fps  495.5 kbps (60.5 kbyte/s)
AUDIO: 32000 Hz, 2 ch, s16le, 64.0 kbit/6.25% (ratio: 8000->128000)

This command also gives you details:

  • tcprobe -i <filename>

However, at this point (transcode 1.0.2) it doesn't show you video bitrates.