[FFmpeg-user] Best way for converting HD 1080i to DVCPRO25 DV?

[Andy Furniss]

Iban Garcia wrote:
> CORRECTION:
>
> #----------------------------------------------------------------------------------
>     $comand="ffmpeg -y -threads 8 -i ".$input_file.".mxf -pix_fmt yuv422p
> -aspect 16:9 -vf \"scale=720:576:interl=1,fieldorder=tff\" -sws_flags
> lanczos -vcodec dvvideo -an ".$output_file.".dv";
> #----------------------------------------------------------------------------------

Why do you need to use dv?

The problem with dv is that the standard says bff - it's possible to 
encode tff with it, but on playback any player will assume bff - so if 
you deinterlace/use a hw player it will look juddery.
If you use a software player like mplayer and override with 
-field-dominance 0 you can make it look OK.

I did a quick test with the command above and on 1080i h264 it produced 
loads of dups - to fix needed -r 25 before outfile.

While it didn't look too bad, that may have been luck to do with the 
source. Also I didn't look closely enough to see what was going on with 
chroma.

Generally interlaced video is softened vertically to avoid interline 
twitter, though this may not be needed as much if you are not playing on 
a true interlaced display.

Even without interlace, video is usually softened somewhat below display 
res (kell factor) though as this is 16:9 anamorphic I suppose it doesn't 
matter, but is something to keep in mind when scaling down if you are 
seeing artifacts.