[FFmpeg-user] best way to transform SD to HD w/ pillarbox and yadif

[Marton Balint]

On Fri, 19 Jul 2019, Carl Eugen Hoyos wrote:

> Am Do., 18. Juli 2019 um 22:25 Uhr schrieb William Caulfield
> <william.caulfield at contentbridge.tv>:
>>
>> I hope I'm getting your intention right here. I had to do this a while back
>> for some PAL files. Split the fields, scale, pad, then interlace.
>>
>> -filter_complex
>> "yadif=1:0,scale=1440:1080,pad=1920:1080:240:0:black,interlace,setdar=16/9"
>
> If your input is interlaced and you need progressive output (as the last
> hardware that was able to correctly show interlaced content died some
> time ago), then the correct order is to crop (if necessary first), then
> deinterlace.

Cropping odd number of rows from the top can cause interlace issues 
obviously.

> If you (for whatever insane reason) want interlaced output and you
> have interlaced input, you should not use a de-interlacer (as it will
> damage the image further), but tell your scaling algorithm that the
> input is interlaced (if the scaler does not support interlaced input,
> simply split the fields, do whatever is necessary with them, and
> put them together afterwards).

I'd be very much suprised if that was true, do you have an example where 
an interlaced scaler provides better quality than yadif=1,scale,interlace?

Thanks,
Marton