2 ms·
> "To the best of my knowledge, H.264 only supports two GOP structures (short = 6 frames / long = 15 frames), both of which operate independently from the playb
by jwr 16y ago
> "To the best of my knowledge, H.264 only supports two GOP structures (short = 6 frames / long = 15 frames), both of which operate independently from the playback speed.
In other words, a short GOP setting produces 8 blocks per second running at 48, and 10 per second running at 60. Assuming a constant bitrate (I know, I know), the throughput of the entire system needs to increase by an additional 20% to handle 60."
I'm sorry, but it needs to be stated: the above isn't true and the calculations have nothing to do with reality. H.264 supports pretty much any GOP structure and you don't get from frames to final bitrate by dividing frame rates by GOP size.
- alexqgb 16y agoDude, chill. Also, read. Accepting that I was mistaken about the rigidity of h.264 (a possibility I acknowledged up front), and assuming that you DID establish a GOP structure of 6 frames (at a constant bit rate) shooting for one minute at 48 fps would produce 80% of the data generated by shooting at 60fps. Indeed, this ratio would be true if you used no compression at all. The point was that in a fixed GOP scheme (again, at a constant bitrate), the difference in FILE SIZE would increase with the difference in frame rate, so the idea that file sizes for 60 fps material would only be marginally larger than those for 48 fps seemed mistaken. My only mistake was in assuming that the GOP is fixed in h.264. I agree that "you don't get from frames to final bitrate by dividing frame rates by GOP size." But then again, I never said you did.