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

[Paul B Mahol]

On 7/12/20, Ben Hutchinson <benhut1 at gmail.com> wrote:
> 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).

I sent patch to fix this.

>
> 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.
>> >> > _______________________________________________
>> >> > ffmpeg-devel mailing list
>> >> > ffmpeg-devel at ffmpeg.org
>> >> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>> >> >
>> >> > To unsubscribe, visit link above, or email
>> >> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>> >> _______________________________________________
>> >> ffmpeg-devel mailing list
>> >> ffmpeg-devel at ffmpeg.org
>> >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>> >>
>> >> To unsubscribe, visit link above, or email
>> >> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>> > _______________________________________________
>> > ffmpeg-devel mailing list
>> > ffmpeg-devel at ffmpeg.org
>> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>> >
>> > To unsubscribe, visit link above, or email
>> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel at ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".