[Story video] Add codec information received from video cache

[gmajoulet]

Description

Add codec information received from video cache.

The type parameter should include the codecs, e.g. type="video/mp4;codecs=vp9", from the JSON response we receive:

"sources":  [
    {
      "url": "url",
      "codec": "h264",
      "type": "video/mp4",
      "bitrate_kbps": 400
    },
    {
      "url": "url",
      "codec": "vp09.00.21.08",
      "type": "video/mp4",
      "bitrate_kbps": 276
    }
  ],

amphtml/extensions/amp-video/0.1/video-cache.js

Line 98 in 2dab872

'type': source['type'],

cc @ampproject/wg-stories

Alternatives Considered

Additional Context

No response

[gmajoulet]

cc @coreymasanto