[MPlayer-dev-eng] [PATCH] demux lavf: Print rotate information as identify msg

[Reimar Döffinger]

On 16 Nov 2012, at 07:21, Xidorn Quan <quanxunzhen at gmail.com> wrote:
> On Fri, Nov 16, 2012 at 2:10 PM, Reimar Döffinger
> <Reimar.Doeffinger at gmx.de>wrote:
> 
>> 
>> 
>> On 16 Nov 2012, at 02:37, Xidorn Quan <quanxunzhen at gmail.com> wrote:
>> 
>>> Hi,
>>> 
>>> This patch print rotate information in metadata of mov file as
>>> identify message with tag "ID_VID_<vid>_ROTATE" to enable frontends
>>> to rotate the video themselves. I'm not sure if adding such output
>>> will break something, so I sent this patch here. Please comment.
>>> 
>>> I tried to make mplayer automatically rotate video according to this
>>> information by inserting vf like vf_ass, but I found that vf_rotate
>>> is too tricky to be used here: it can only rotate 90 and 270, but
>>> the angle may be 90, 180, or 270. I don't have any idea of the right
>>> way to implement this feature. Any suggestion?
>> 
>> 180 degree is done via flip flag, which does not need any software
>> processing.
>> 
> 
> 180 degree rotation is not the same as flipping. Flipping just make
> images upside-down. vf_flip + vf_mirror or vf_rotate * 2 are two
> feasible method to implement 180 degree rotation.

Yes, you're right, you'd also need mirror.
Which makes the whole thing possibly quite complex when switching between files or worse video streams in the same file that have different rotate properties.
Concerning the patch you sent: I think it should be fine to commit.