[FFmpeg-user] Dimensions of the input video as a variable

[Wolfgang Hugemann]

> ffprobe can be used to get width and height for the showwaves size
> option.

This set me on the rigth track!
This is what my Windows batch file now looks like:

SET FFM="c:\programme\ffmpeg\bin\ffmpeg.exe"
SET FFP="C:\programme\ffmpeg\bin\ffprobe.exe"

for /f "tokens=5 delims==_" %%i in ('%FFP% -v error -of flat^=s^=_ 
-select_streams v:0 -show_entries stream^=width %1') do set W=%%i

for /f "tokens=5 delims==_" %%i in ('%FFP% -v error -of flat^=s^=_ 
-select_streams v:0 -show_entries stream^=height %1') do set H=%%i

%FFM% -y -i %1 -filter_complex 
"[0:a]showwaves=s=%W%x%H%:mode=line,format=rgba[waves];[0:v]setsar=1:1,format=rgba[video];[waves][video]blend=all_mode='addition'" 
-c:v libxvid -c:a copy %~dpn1_wav%~x1

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The line breaks stem from sending this per e-mail.

Please note that the colour format must be set to rgba in order to make 
black background of the waves transparent.

Thanks a lot!
Wolfgang