Converting any videoclip into ready playable audio files wit

[tubefriend]

I developed this while creating test signals. You need the following programs installed:
- an video converter like AVIDemux
- the Imagemagick and ffmpeg programs
- an Audio converter like Audacity (should be already well known to you)

The following guide uses the values for my own standard but can easily change to numbers to your "club standard"

Part one:

Load the video into your video converter
Grayscale it (saves time if you use this as your first filter)
Crop and/or Stretch it until it fits your aspect ration
Resample it to your framerate (in my case 6.25Hz)
Resize it to your image ratio

Turn the video by 90° and flip its sides if your standard requires it

Save the video in an uncompressed format like AVI with YV12 (or you get major ringing artifacts)

Now you can play back this file on your computer to see it just like it will look on your NBTV device.


Part two:

Wave your magic wand and spell something like:

convert ccau_512kb.avi -brightness-contrast 0,-20% -brightness-contrast +12%x0 -fill black -draw "line 0,0 31,0" -draw "line 0,1 0,23" -fill "rgb(63,63,63)" -draw "line 1,0 2,0" ccau_512kb.gray

This does the following operations
- read ccau_512kb.avi
- adjust contrast and brightness to get room for the sync pulses
- set drawing color to what will now be sync level
- draw an line on the top that will be the frame sync now
(leave this part away for your missing pulse "club standard")
- draw an line on the left that will be the line sync now
- set drawing color to what is black level now
- draw two pixels in black level to improve sync in my stadard
(leave this part away for your "club standard")
- save file in raw samples to ccau_512kb.gray

An word of warning:
Always specify the .gray extension for the output file and never any image file or the program fills your directory within few seconds with literally hundreds to thousands of separate image files.


Part three:

Run Audacity and import your file xyz.gray as 8-Bit unsigned with the sampling rate set to the pixelrate of your standard (with mine it is 4800Hz)

Convert the samples to your output samplerate. Use 44.1kHz if you want to burn this onto an CD. Select the ZOH-Interpolator in the preferences menu because the "high quality" will fail badly for our signals and produce massive ringing.

Save as wavefile and playback or burn to CD.