Hey Everyone, Given 2 hours worth of recorded footage, under the same codec (usually H264/AVC) which do you think is better? 720p @ 6GB to 7GB or 1080p @ 9GB to 10GB Would the size restrictions to 1080p perhaps constrain the bit-rate in such a way as to make the increased resolution a negligable tradeoff? For that matter, would a 720p encode at the above settings look better scaled to 1080p, than the 1080p encode at the above setting?
As 1080p at 9GB calculates to the same bitrate as 720p at 6GB... (6GB/720)*1080 = 9GB ...then I would assume that there would be no tradeoff whatsoever and so encoding at 1080p is the best course of action. Or am I being crazy?
It somewhat can depend on the image content of the footage. Best way to tell is to take a representative sample (say, about a minute and a half's worth) from various parts of the video, and simply do some test encodes. It also depends on what your source resolution is. 1080i60? 1080p60? 1080p30? 1080p24? If your footage is 1080i60, I definitely recommend not deinterlacing it (unless your target is streaming video, as I know of no widespread methods of streaming that allows any more than 30fps) as you'll lose half the temporal resolution. mooseblaster: That's not really entirely accurate. That only takes the vertical resolution into account, when you also have a fairly big difference in horizontal resolution (1280x720 vs 1920x1080). Better way to do it is to compute the total number of pixels and then divide the bitrate by that. Gimme just a sec and I'll edit this with the math. Edit: Ok, did the math. It's a bit unconventional, but I basically computed the average number of bits per frame with each choice. 1280x720 = 921600 pixels 1920x1080 = 2073600 pixels 1080p = 2.25 * 720p 1GB = 8589934592 bits 6GB = 51539607552 bits 9GB = 77309411328 bits 720p @ 6GB = ~55924 bits per frame 1080p @ 9GB = ~37283 bits per frame Given this, it looks like 720p has the objective advantage. Depending on your footage, this may or may not be borne out in practice. I'm also a little bit tired ATM, so if my math or methodology is off then please let me know.
Hrm... Interesting calculations. I guess the best thing would be to do some encode tests, though it would be nice trying to avoid the lengthly processing times. (^_^);
Most full-lenght movies with DTS track are usually made to fit on a dvd5 at 720, So if you got a stereo track 2 hours would look great at around 4.3gb
Ya, scene encoders tend to drop the ball on quality in exchange for one-upping the competition with faster releases. Though some groups are trying to make a name for themselves in terms of quality. Though, since in our case it's simply for personal video archiving, it would really be up to the user to find the best space vs quality for the material.
