[FFmpeg-devel] [PATCH]lavfi/telecine: Mark telecined frames as interlaced

[Carl Eugen Hoyos]

Am So., 12. Apr. 2020 um 11:35 Uhr schrieb Paul B Mahol <onemda at gmail.com>:
>
> On 4/12/20, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> > Am So., 12. Apr. 2020 um 10:38 Uhr schrieb Paul B Mahol <onemda at gmail.com>:
> >>
> >> On 4/11/20, Paul B Mahol <onemda at gmail.com> wrote:
> >> > On 4/11/20, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> >> >> Am Sa., 11. Apr. 2020 um 15:10 Uhr schrieb Paul B Mahol
> >> >> <onemda at gmail.com>:
> >> >>>
> >> >>> On 4/11/20, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> >> >>> > Am So., 5. Apr. 2020 um 02:05 Uhr schrieb Carl Eugen Hoyos
> >> >>> > <ceffmpeg at gmail.com>:
> >> >>> >>
> >> >>> >> Am So., 5. Apr. 2020 um 01:02 Uhr schrieb Carl Eugen Hoyos
> >> >>> >> <ceffmpeg at gmail.com>:
> >> >>> >> >
> >> >>> >> > Am Sa., 4. Apr. 2020 um 00:44 Uhr schrieb Carl Eugen Hoyos
> >> >>> >> > <ceffmpeg at gmail.com>:
> >> >>> >> > >
> >> >>> >> > > Am Sa., 4. Apr. 2020 um 00:40 Uhr schrieb James Almer
> >> >>> >> > > <jamrial at gmail.com>:
> >> >>> >> > > >
> >> >>> >> > > > On 4/3/2020 6:37 PM, Carl Eugen Hoyos wrote:
> >> >>> >> > > > > Am Fr., 3. Apr. 2020 um 23:19 Uhr schrieb Carl Eugen Hoyos
> >> >>> >> > > > > <ceffmpeg at gmail.com>:
> >> >>> >> > > > >
> >> >>> >> > > > >> Attached patch marks actually telecined frames as
> >> >>> >> > > > >> interlaced,
> >> >>> >> > > > >> other frames as progressive.
> >> >>> >> > > > >
> >> >>> >> > > > > New patch with changes to fate attached.
> >> >>> >> > > > >
> >> >>> >> > > > > Please comment, Carl Eugen
> >> >>> >> > > >
> >> >>> >> > > > Those yadif tests look wrong. The patch shouldn't affect
> >> >>> >> > > > them.
> >> >>> >> > >
> >> >>> >> > > Clearly, thank you!
> >> >>> >> > >
> >> >>> >> > > New patch attached, it should now only change the telecined
> >> >>> >> > > frames and leave the other frames as they are, the setfield
> >> >>> >> > > filter can be used to force a progressive setting for them.
> >> >>> >> >
> >> >>> >> > New patch attached that also sets top_field_first
> >> >>> >>
> >> >>> >> Which had the effect that fate is correct again, new patch
> >> >>> >> attached.
> >> >>> >
> >> >>> > Patch applied.
> >> >>> >
> >> >>>
> >> >>> This was never approved by me.
> >> >>
> >> >> You reviewed it on irc and correctly pointed out the missing bits.
> >> >
> >> > Lies, I was against that idea from start.
> >> >
> >> >>
> >> >>> So revert it ASAP!
> >> >>
> >> >> What should be changed about it?
> >> >
> >> > Return of code as it was before this pointless change.
> >> > I see no good out of it.
> >>
> >> I gonna revert this ASAP!
> >
> > Could you explain why it is wrong to mark interlaced frames
> > as interlaced?
>
> The frames are not interlaced.

Using the usual 3:2 telecine, the filter outputs two progressive
frames, followed by three interlaced frames, the patch should
mark the interlaced frames as interlaced and I believe it does.

> I thought you knew that interlacing destroys half of data.
> Telecine does not destroys data.

Telecine duplicates some data, leading to interlaced frames.
A (perfect) detecine process can remove the duplicated data
(and the interlaced frames).

Carl Eugen