[FFmpeg-user] [Bulk] Re: Problem with vf pad ... help please

[Tim Nicholson]

On 17/09/12 14:50, Mark Himsley wrote:
> On 17/09/12 08:44, Christian Ebert wrote:
[...]
>> Thanks for the pointers - now I know why I had this nagging
>> suspicion that something was not quite right DAR-wise with my
>> transcodings. For the web I will probably crop so I can stay with
>> "simple" aspect ratios, something like:
>>
>> -vf crop=iw-18:ih,yadif,scale=640:480,setsar=1:1
> 
> Does crop default to centred (I honestly cannot remember)? Otherwise
> you'll crop all 18 pixels off one edge.
> 
> And, if your video has sub-sampled chroma (422 or 420 for example) then
> you can only crop to even numbers, and you end up cropping 8 pixels off
> one side and 10 pixels off the other.
> 

Isn't that the root of the 702/704 pixel argument....?

> But, yes, that's the idea.
> 


-- 
Tim