H264 has no such limitation regarding gop structure. The levels (3.0, 4.1 etc) define (slightly indirectly) the DPB (decode picture buffer) size. This is how many frames must be held in memory at one time. The gop itself is not limited.
Furthermore the compression rate for high frame rate actually increases for live action as there has been less change between the frames and even taking a fixed framerate.
There are compromises to be made and faster framerate with a fixed bitrate may not be great for all usages but I think that you are being very, and unduly, pessimistic here.
From my experiences at 720p 60fps and a 6 Mbps stream (which we currently have deployed) and a nice encoder you are looking at a very nice picture.
Very interesting. Thanks for the detail. I guess the fixed GOP structure must be limited to HDV (MPEG-4). That flexibility is pretty awesome.
For what it's worth, I suspect what you describe (720p60 @ 6Mbps) is more than fine for most people. In other words, Cameron's idea that people will be going to theaters because of magical picture quality seems like wishful thinking. I suspect people go to theaters because they like going to theaters. It's social. It's big. It's immersive and (relatively) distraction-free - all part of a fun night out.
Are they going to go home to 720p60 @ 6Mbps and think 'gah!'. Unlikely.
