[FFmpeg-devel] [PATCH] ffplay: support rotated video.

Don Moir donmoir at comcast.net
Fri May 23 08:40:35 CEST 2014


>> I guess what you are saying it might be something like "90.5" or something.

>Yes. 90.999 would raise 90 too unless you round btw.

>> Could be one degree off. Not sure it would display where someone would
>> notice a one degree difference.

>There is no reason to drop that accuracy. The orientation matrix in MOV
>has a relatively high one, there is no reason to drop it just to save 3
>strcmp on 2-3 characters called only once at the beginning of the program.

Thanks for your explanation and not arguing about the strcmp. I was not aware it could have fractional degrees. Now that I do 
though, I probably am still going to drop that fraction. I doubt it makes a difference but I might just see what it does if I add a 
fractional degree to it like .99. Maybe you could also fake it in the code to see what kind of difference it might make.

Not sure why a video would have a fractional degree unless it was a bug. Just trying to be clear on it and dealing with width height 
display issues etc.

>> Can it be radians and how would you know
>> that?
>>

>See the other thread where I sent the updated patchset. It should answer
>all your questions.

>> Do you have a video with an odd rotate value ?

>Not yet, but it's almost free to deal with that. 90, 180, and 270 cases
>are just exception, and I don't want to catch them because of an
>inaccuracy.


>It's more complex to write a matrix leading to 90.1 degrees
>than 90 degrees, so there is no reason to rotate 90 instead of 90.1 in
>that situation.

I think this is mis-stated. Almost free for 90 degree and more complex for 90.1 so no reason to rotate 90 instead of 90.1?



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