Add stream method to identify a video's rotation.

[jacobischwartz]

Q	A
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Fixed tickets	no
Related issues/PRs	#117 #199
License	MIT

What's in this PR?

Add a stream method to easily identify the rotation of a video.

Why?

There seems to be a common confusion regarding the dimensions of a video that have been rotated. FFProbe can report the width and height as the reverse of what the video appears to have. iPhones create portrait video that exhibit this issue, for example. But by inspecting the rotation of a video, this issue can be accounted for. By providing a getRotation method alongside the getDimensions method, it will be easier for users of this library to discover the reason for their confusion.

Here are some examples of people exhibiting this confusion, sometimes with this library, sometimes with FFProbe vanilla:
#117
https://forums.creativecow.net/docs/forums/post.php?forumid=291&postid=888&univpostid=888&pview=t
https://stackoverflow.com/questions/53339787/ffmpeg-get-orientation-inverted
#199
https://stackoverflow.com/questions/13093295/how-can-i-determine-video-rotation-orientation-in-php-ffmpeg-phonegap

Here's a help page from this library that discusses the issue. This new method is self-documenting code that would assist users who go down the same rabbit hole that I did:
https://github.com/PHP-FFMpeg/PHP-FFMpeg/wiki/How-to-rotate-video-based-on-smartphone-rotate-meta-tag

Example Usage

$stream = FFProbe::create()
        ->streams($video_filepath)
        ->videos()
        ->first();
$rotation = $stream->getRotation();
$dims = $stream->getDimensions();

// Now we can reverse dimensions
if((90 === $rotation) || (-90 === $rotation)) $dims = new Dimension($dims->getHeight(), $dims->getWidth());

[jens1o]

Thanks for your contribution! Could you add a test for this, please? :)

Then I'm happy to merge this into the next minor release. :)

[jacobischwartz]

@jens1o test added.

[jens1o]

Thanks, I'll take a look! :)

[nickano]

Hey jensto, thanks for this tweak - do you think you'll have time to fix the conflicts and get this ready for release again, as I could see it being very useful :)

Thanks