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View Full Version : x265 (HEVC) basic encoder settings?


Yog_Sothoth
21st November 2021, 11:41
Hello. It's all too complicated for me. Could you just tell me what the basiс settings for encoding are?

For example:
Profile.
Level.
Preset.
Scaling mode (for downscaling).
Any other options I need to change aside from bitrate, resolution, rate control mode? As I understand, 2-pass encoding is better, but people still use constant quality one, why?

Atak_Snajpera
21st November 2021, 12:26
Because nobody aims for CD/dvd anymore. 2-pass is a waste of time and space

RanmaCanada
21st November 2021, 19:59
Just pick a CRF and a speed, and you're good to go. The baseline of the speed profiles does a "good" job of getting you decent quality without massive tweaking. Slow or lower is better.

Yog_Sothoth
22nd November 2021, 11:18
Just pick a CRF and a speed, and you're good to go. The baseline of the speed profiles does a "good" job of getting you decent quality without massive tweaking. Slow or lower is better.
For which bitrates hevc performs better compared to avc? I've tested them on 6 Mb/s and I think they are pretty similar, but avc is slightly better (if you zoom in and take a closer look). Is that correct, I thought it shouldn't be the case? I've also tried higher and lower bitrates and at all them, they perform pretty similar, but at around 3 Mb - hevc certainly wins, and at 12 Mb - avc slightly wins. So, where is that threshold between bitrates for hevc and bitrates for avc?

RanmaCanada
23rd November 2021, 02:42
For which bitrates hevc performs better compared to avc? I've tested them on 6 Mb/s and I think they are pretty similar, but avc is slightly better (if you zoom in and take a closer look). Is that correct, I thought it shouldn't be the case? I've also tried higher and lower bitrates and at all them, they perform pretty similar, but at around 3 Mb - hevc certainly wins, and at 12 Mb - avc slightly wins. So, where is that threshold between bitrates for hevc and bitrates for avc?

It all depends on the source material. But if my answer is not good enough, I am sure one of the more knowledgeable users will chime in.

videoh
23rd November 2021, 03:55
I am sure one of the more knowledgeable users will chime in. You seem pretty knowledgeable to me. Believe.

@all

Happy Thanksgiving!

benwaggoner
29th November 2021, 21:19
For which bitrates hevc performs better compared to avc? I've tested them on 6 Mb/s and I think they are pretty similar, but avc is slightly better (if you zoom in and take a closer look). Is that correct, I thought it shouldn't be the case? I've also tried higher and lower bitrates and at all them, they perform pretty similar, but at around 3 Mb - hevc certainly wins, and at 12 Mb - avc slightly wins. So, where is that threshold between bitrates for hevc and bitrates for avc?
HEVC generally takes around 50-70% the bitrate to hit the same quality as H.264 at the same presets (so x265 slower than x264). High enough and bitrate and quality will converge. Best comparisons are with H.264 at the lowest bitrate that achieves a subjective quality target.

Comparing with 2-pass VBR is better than just CRF, as CRF values aren't equivalent across codecs or content types.