Hello,
do you know what the minimum and maximum values are for the pix_th parameter of the ffmpeg's blackdetect filter ?

Thanks !

pixel_black_th, pix_th

The documentation says :

Code:
pixel_black_th, pix_th

    Set the threshold for considering a pixel "black".

    The threshold expresses the maximum pixel luminance value for which a pixel is considered "black". The provided value is scaled according to the following equation:

    absolute_threshold = luminance_minimum_value + pixel_black_th * luminance_range_size

    luminance_range_size and luminance_minimum_value depend on the input video format, the range is [0-255] for YUV full-range formats and [16-235] for YUV non full-range formats.