[FFmpeg-user] Default Lanczos kernel?

[Werner Robitza]

All,

I was looking for some documentation for the Lanczos resampling
filter, but I cannot find any mention of the default value for the
alpha parameter.

I see this in swscale.h:

    For SWS_LANCZOS param[0] tunes the width of the window function

I also see that SWS_PARAM_DEFAULT is 123456, whose purpose I don't
fully understand, but clearly it's not the right value. Or is it 6, as
shown in utils.c, line 412?

Werner