720p vs 1080p video 720p#
720p vs 1080p video 1080p#

720p vs 1080p video 720p#

I would conclude that the blurriness of the 720p is an effect of the re-encoding rather than loss of details due to the downscaling alone. Means the 720p went through an extra encoding step, if I read your post correctly.

720p vs 1080p video 1080p#

I understand you compare the 1080p original from the camera with a re-encoded (re-rendered) 720p frame of DaVinci. The 720p was not downscaled using a video player, it was rendered at that resolution in DaVinci Resolve. I'm not saying encoding at the original resolution isn't ideal if there's no bitrate limitations to worry about, but the difference in detail you can see is often negligible to none, even when comparing still frames. I converted to YV12 first for LSFMod (screenshot 3). To 720p and back with a little extra sharpening. The 1080p image downscaled to 720p then upscaled again in an Avisynth script (screenshot 1).Дownscaling to 540p and back still looks a tad sharper than the 720p image upscaled by WMP, although it's hard to know for sure as they're not the same frame (screenshot 2). You are at the mercy of the player's/TV's upscaling in that respect. I'd be willing to go out on a limb and say that's more blurring due to the downscaling and/or upscaling not being sharp than it is a loss of detail as such. I generally use CRF18 for 720 and CRFp, x264's medium speed preset or slower and the film tuning, but once again, that's just me. The file sizes will vary but after a few encodes you'll settle on a quality you're happy with that gives you a bitrate you're happy with. CRF encoding produces the same quality at the same bitrate, with the same encoder settings (if you ran a CRF encode and used the resulting bitrate for a 2 pass encode, the quality would be virtually identical) and as CRF only requires a single pass it's a fair bit faster. I'd still not bother with 2 pass encoding unless there's a good reason. There's a guide to resolution and viewing distance here. I'm generally not close enough to see 1080p worth of detail, so if I was forced to encode at 4000 kb/s all the time and didn't want to mess around checking the quality of each encode I'd probably stick to 720p and keep the encoding quality high, but that's just me. How far you sit from the screen can be a factor. At CRF18, which is a fairly high quality for x264, I've had 720p encodes come in at under 2000 kb/s, so a 1080p encode of the same video at 4000 kb/s would probably look good, but for harder to compress video 4000 kb/s wouldn't be unrealistic for 720p, so at 1080p the quality wouldn't be all that special. It depends how much grain there is, and how much action and detail etc. Will be there any benefit if encode in 1080p? and if consider technical overview, will be there any difference while watching in big screen? The problem is no two videos require the same bitrate for the same quality.

assume source is bluray and i will encode in 4000 BitrateД§20=>encoding will take less time compare 1080p. Sorry i should have be more specific about the encoding.

I tend to encode at 720p unless the source has lots of fine detail that'll be lost when downscaling (which often isn't the case) and encode using a decent quality setting, but there's probably no simple answer. You can probably get away with slightly lower quality for 1080p, as the encode doesn't need to be upscaled on playback (or upscaled less), as upscaling also upscales any compression artefacts making them easier to see.

You can't control the bitrate as such, but the quality will be the same for a given quality setting (CRF value as x264 calls it).

Most people use quality based encoding rather than specifying an average bitrate for the x264 encoder. At low bitrates you're more likely to see compression artefacts for 1080p because there's more video to encode with the same number of bits available to encode it. If you use a high enough bitrate it probably won't make any difference (aside from any possible detail loss through resizing down) as if the quality is high for 1080p it'll be high for 720p, even if the bitrate is higher for 720p than would have been necessary for a decent quality. It depends on the source and the bitrate.