[FFmpeg-user] De-telecine, deinterlace, and filter chains

[Andy Furniss]

Billy wrote:
> On 1/23/2017 12:02 AM, Mike Brown wrote:
>>> But this method didn't seem to have any real effect on my video.
>>> It's a long video, so I have made a shortened version available
>>> to see if anyone has seen such a case. It's in 1080p and 23.97
>>> fps. I'd like to save it in a similar frame rate and size, but to
>>> be honest, the frame rate could be just about anything as long as
>>> the interlacing was gone.
>>
>> It is 29.97, not 23.97.
>>
>>> I tried checking for interlacing on the original video... None of
>>> the frames are set as interlaced when I ran ffprobe.
>>
>>> The (short) video (6MB): https://www.datafilehost.com/d/5474b665
>>
>> So, is this video the original, or the output of something you
>> tried?
>>
>> If it is the original, I'm not sure you can do anything about it.
>> Why, because it is progressive video.  To IVTC requires interlaced
>> video @ 59.94 fields per sec, so that the 2:3 pulldown pattern can
>> be found and removed.  You can't find the 2:3 pulldown pattern in
>> progressive video. While we humans can see the 2:3 pulldown
>> pattern, I'm not sure what filter can.
>>
>> Maybe someone has a way, but I certainly do not know it.
>>
>> MB
>>
>
> Yep. 29.97. You watched a shortened "original."
>
> I produced it for you thusly so you could wince along with me:
>
> ffmpeg -ss 28:21 -t 6 -i in.mp4 -c:v copy out-short.mp4
>
> The results of my deinterlacing attempts looked the same as this.
>
> Thanks for your comments. My hope is that the miscreant who
> transcoded it into progressive and left all of the artifacts...
> doesn't do this any more. My eyes hurt.

Vid looks like it's scaled up from 480 height and pillarboxed, so the
weave is not line for line anymore.

It's probably been scaled as progressive which on strong chroma will (I
think) be un-mendable. Saying that the sample can be scaled down to 480
and the weave is 1:1 again, which holds out the possibility that you
could make it interlaced again with tinterlace and try to get IVTC to
run on that.

No idea as to exact commands - just a bit of hope you could make it a
bit better - but not perfect like you could if you had the "real" ntsc
master.