[FFmpeg-user] (de)-interlacing question

[Moritz Barsnick]

On Mon, Nov 21, 2016 at 22:32:39 +0100, Toerless Eckert wrote:
> 2. The 50i material i get from TV nowadays seems to be 720 at 25p material
>    that was motion interpolated to 50p, scaled down and then sent interlaced.
>    Aka: every second field is probably just invented by motion interpolation.
>    Which is quite annoying because IMHO this makes 50% of the bits mostly
>    fabrication instead of actual source bits.

(Well, if they don't have intermediate frames originally, but they do
have bandwidth to spare, you can't blame them.)

Speaking for German DVB-S2 with 720 at 50p: If you look at that material
frame by frame, you will notice that it's not actually interpolated,
but instead frames are just repeated (when the input material was
recorded at 25p). After inspection of a recording, you can just insert
"-vf fps=fps=25". It won't make your target video *much* smaller
though, as repeated frames probably compress quite nicely (with H.264),
but you will notice the difference in size. And you won't notice a
difference in motion. ;)

Moritz