[FFmpeg-user] DOWN CONVERSION ISSUE: From MXF (1080i AVC Intra) - MBAFF "interlacing" to DVCPRO

Tim Nicholson nichot20 at yahoo.com
Tue Mar 27 10:56:22 CEST 2012

On 27/03/12 07:05, Iban Garcia wrote:
> 2012/3/26 Tim Nicholson <nichot20 at yahoo.com>
>> On 26/03/12 15:29, Iban Garcia wrote:
>>> Exact!!
>>> But the issue *has been solved* using next:
>>>  -vf "scale=720:576:interl=1,fieldorder=tff" -vcodec dvvideo
>> Ahh, the difference between scale=720:576:1 and scale=720:576:interl=1 !!
>> I think the documentation is unclear on the fact that for width and height
>> you
>> just specify an expression, but for interlace you need to specify the
>> parameter
>> as well.
>> *But* your command, as above is setting the output field order to tff when
>> DV is
>> bff so you will get motion judder. I really think you should use:-
>> ...vf "setfield=1, scale=720:576:interl=1, fieldorder=bff"...
>> or:-
>> -vf "setfield=0, scale=720:576:interl=1"...
>> if your source is already bottom field first (unlikely).
>> Umm... it is strange, because if I use
> -vf "setfield=1, scale=720:576:interl=1, fieldorder=bff"
> I get incorrect field order when playing (motion judder)
> The only way I have got the video correctly played is using "tff" instead
> of "bff".

This would suggest your original material is already bff but flagged as tff, that way
ffmpeg thinks nothing needs to be done when you specify tff as it is that already, 
wheras my command forces a flip.

It shows how important it is to test the parameters thoroughly before use...:)


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