[FFmpeg-devel] Bug in FFMPEG video filter TINTERLACE needs fixing

[Ben Hutchinson]

According to the documentation on the TINTERLACE video filter, the filter
mode called MERGEX2 will "Move odd frames into the upper field, even into
the lower field, generating a double height frame at same frame rate." But
it doesn't do this, at least in some cases (not sure about all cases). The
first frame in a sequence should be considered frame one (an odd frame) for
the purpose of this interlacing algorithm. However, that is not what's
happening in my experience. At least with raw video (using "-f rawvideo")
it's treating the first frame as frame zero (an even frame) and thus my
first frame (which contains top-field data) ends up getting put into the
bottom-field of the output video, and this is messing up the output. Please
fix this.