Videos can expand to massive sizes if dimensions are zero

[turt2live]

Event (redacted for privacy):

{
  "origin_server_ts": 1529077392256,
  "sender": "@redacted:matrix.org",
  "event_id": "$1529...KmaO:matrix.org",
  "unsigned": {
    "age": 9619
  },
  "content": {
    "body": "redacted.mov",
    "info": {
      "mimetype": "video/quicktime",
      "thumbnail_info": {
        "mimetype": "",
        "h": 0,
        "w": 0,
        "size": 0
      },
      "h": 0,
      "thumbnail_url": "",
      "w": 0,
      "duration": 0,
      "size": 31788779
    },
    "msgtype": "m.video",
    "url": "mxc://matrix.org/StbgzQeZPW..."
  },
  "type": "m.room.message",
  "room_id": "!FPU...:matrix.org"
}

Result (blurred for privacy):

[lukebarnard1]

So seemingly, we need to use videoWidth and .videoHeight once the video is loaded.

We should handle info being present but values being set to 0.

Perhaps if the ratio in info is not < 1.0 and > 0.0, we should just default to naturalXXX.

[turt2live]

Brief testing shows that this also applies to negatives, so capping between 0..1 seems like a good plan.

A 1x1 video renders as expected: a single pixel.

[ara4n]

just tested this with current thumbnailing logic and it seems to be okay.