Support for multiple sources (one video, multiple codecs) and levels (resolution/bitrate)

Marked #1409216: Levels as a duplicate. Wanting to support multiple resolutions/bit rates is fundamentally tied to having more than a single source for a video.

I'd certainly like to support multiple video resolutions and codecs. It hasn't been done due to time and because I have no current need for the functionality. I'd be up for reviewing and potentially committing a patch at this point.

For implementation what I'm thinking is that sources becomes an array that is passed to the theme function. The theme function would then process the array into a $sources variable that is passed to the template file and also add to the JW Player config variable. Because most people will only ever pass a file object to the theme function perhaps this could be an additional option for advanced users (choose one or the other).

Something to work out is the expected format of the array itself. According to the JW Player documentation levels can be used for multiple bit rates, which requires additional parameters for width and bitrate, or for multiple codecs, which only requires the video URL. Here is what the array for the multiple formats would look like:

$html5_levels = array(
  "http://example.com/videos/video.mp4",
  "http://example.com/videos/video.webm",
  "http://example.com/videos/video.ogg",
);

And for variable bit rates:

$variable_bitrate_levels = array(
  array(
    'bitrate' => 300,
    'file' => 'http://example.com/videos/video_300k.mp4',
    'width' => 320,
  ),
  array(
    'bitrate' => 600,
    'file' => 'http://example.com/videos/video_600k.mp4',
    'width' => 480,
  ),
  array(
    'bitrate' => 900,
    'file' => 'http://example.com/videos/video_900k.mp4',
    'width' => 720,
  ),
);

Another potential option to unify this would be to make the video path the key, with the bitrate and width an array of optional values:

$hybrid_levels = array(
  'http://example.com/videos/video_300k.mp4' = array(
    'bitrate' => 300,
    'width' => 320,
  )
  'http://example.com/videos/video_900k.mp4' = array(
    'bitrate' =>  900,
    'width' => 720,
  )
);

One scenario that the JW Player documentation doesn't account for is multiple bit rates in multiple formats. I'm not sure if that is even possible. Any thoughts on the structure of the array are welcome.

Attached is some work in progress towards this goal. It replaces the file_url and file_mime variables with a new sources variable that is an array of file_url and file_mime pairs. It seems to work fine to support multiple video formats. I've yet to start working on the bitrate switching problem. Feedback appreciated!

Attached is an update patch that also works with adaptive bitrates. Some minor documentation changes snuck into the patch as well. Here's the theme call I've been using to test (replace 'my_sites_preset' with a preset from your test site):

$video = array(
  'sources' => array(
    array(
      'file_path' => 'http://carbuyer.co.uk/sites/carbuyer/files/CB_Kia_Rio_BR_HD.flv',
      'bitrate' => '1600',
      'width' => '1280',
    ),
    array(
      'file_path' => 'http://carbuyer.co.uk/sites/carbuyer/files/CB_Kia_Rio_BR_SD_0.flv',
      'bitrate' => '768',
      'width' => '432',
    ),
  ),
  'preset' => 'my_sites_preset',
);

theme('jw_player', $video);

I'm tempted to commit this work now as it is needed for one of my own projects but getting some feedback first would be ideal.

I ended up committing the changes as this was needed for a project I'm working on. Feedback and changes are still welcome. I'll be waiting a little bit before creating a new release with the change.

@fugazi You're right that better support for multiple videos in a single field should be added. I've created #1555960: Expose multiple file support to field formatter for the request.