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

[Ben Hutchinson]

I was assuming it started from 1, because in the NTSC video standard (which
is of course where the concept of interlaced video originated), the first
field is called field 1. Field 1 contains the first full line of displayed
video (though technically field 2 contains the first image data, one line
above the first displayed line of field 1, although it's only the right
half of that line).

On Sat, Jul 11, 2020 at 4:07 AM Paul B Mahol <onemda at gmail.com> wrote:

> On 7/11/20, Ben Hutchinson <benhut1 at gmail.com> wrote:
> > I was reading it directly from the official FFMPEG website.
> > https://ffmpeg.org/ffmpeg-filters.html
> > All the info about the TINTERLACE filter I got from reading the info
> there.
> >
>
> OK, lets try again, where have you read that first frame is always an
> odd frame, one with 1 number.
> FFmpeg counts from 0.
>
> > On Fri, Jul 10, 2020 at 2:14 AM Paul B Mahol <onemda at gmail.com> wrote:
> >
> >> On 7/8/20, Ben Hutchinson <benhut1 at gmail.com> wrote:
> >> > 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
> >>
> >> Where is this written?
> >>
> >> > 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.
> >> > _______________________________________________
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