A few weeks ago I recorded The Da Vinci Code from high definition TV, since I was too busy to watch it during broadcast, and in any case I wanted to test out the Panasonic Blu-ray recorder I was reviewing. The recorder had to go back to Panasonic, so I used it to burn the movie to a BD-RE disc (ie. re-writable). Then, before I had a chance to watch it, the formal Blu-ray release of the movie (on a massive two disc special edition) was sent to me. So yesterday I thought I’d compare a couple of frames to see if there is any marked difference between a 12-ish Mbps MPEG2 free to air HD broadcast and a 24.44Mbps MPEG4 AVC Blu-ray version. I ripped a few thousand frames from the latter in preparation, and then started to try finding matching frames from the former.
It wasn’t to be. The first thing I noticed was that the resolution of the TV version was 1,440 by 1,080 pixels. I had forgotten that WIN TV, which was the broadcasting station for the movie, still uses the lower resolution (full HD resolution is, of course, 1,920 by 1,080 pixels). Not really comparable in that case.
And then I compared a frame from each. The Blu-ray was 2.35:1 while the TV version was 1.78:1. Here is the same frame from both (Blu-ray top, TV bottom):
Note the reformatting. The TV frame doesn’t just have the edges lopped off to make it fill up the screen. It has them somewhat lopped off, but more of the top and bottom of the frame is presented as well.
So, even with HDTV, you may well not be getting the original aspect ratio.