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+--- Thread: How to keep quality...? (/thread-92.html)
How to keep quality...? - Peter82kr - 04.09.2017
Hi Selur.I got question.
How to setup Hybrid to keep quality using minimum possible bitrate?
There is something like quality/bitrate calculator in hybrid?
Sorry I Am noob.
I searched forum using word: "quality" & I dont find anything interesting.
PS:I want to convert video from h264 to h265 using minimum possible bitrate & keep quality.
RE: How to keep quality...? - Selur - 04.09.2017
Quote:How to setup Hybrid to keep quality using minimum possible bit-rate?[/quote9No, since there is no objective way to calculate 'quality' so how could there be something that measures bit-rate in relation to 'quality' ?
The answer is simple, but you probably won't like it.
So not loose any quality, you need to use lossless encoding, to archive the lowest bit rate at the same time you simply need to max out all the other settings.
Problem with lossless encoding is that the output will be a lot larger than you input file (unless it also was encoded using a lossless encoding mode).
The hard truth is unless you use lossless encoding you will always lose quality.
[quote]There is something like quality/bitrate calculator in hybrid?
Since this dilemma is bugging a lot of folks, the x264 and x265 developers support something that is called 'constant rate factor' (crf) which is kind of a quality/loss indicator.
In general (assuming the other settings stay the same):
- using a lower crf means the output will loose less quality/informatio, but will be large (crf = 0 <> lossless encoding)
- using a higher crf value means the output will be smaller, but also loose more quality/information
Cu Selur
Ps.: Reading http://slhck.info/video/2017/03/01/rate-control.html might help to shed some light on the bitrate distribution (rate control) modes used in x264&x265.
RE: How to keep quality...? - Peter82kr - 04.09.2017
Where i can find this crf setting in hybrid?Its possible to use it?
RE: How to keep quality...? - Selur - 05.09.2017
- Set 'x265->Main->General Settings->Encoding mode' to 'constant rate factor (1-pass)'
- Set 'x265->Main->General Settings->Constant rate factor' to the value you want.
Cu Selur
RE: How to keep quality...? - mparade - 06.09.2017
(04.09.2017, 11:08)Peter82kr Wrote: Hi Selur.I got question.
How to setup Hybrid to keep quality using minimum possible bitrate?
There is something like quality/bitrate calculator in hybrid?
Sorry I Am noob.
I searched forum using word: "quality" & I dont find anything interesting.
PS:I want to convert video from h264 to h265 using minimum possible bitrate & keep quality.
I would use x265 main10 profile, start with CRF=24 (I both started and stopped here). I would use some slower preset, like veryslow.
And that's all. You will not be disappointed with the quality. This is how CRF encoding works. Best for archiving purposes and if you are going to play back your archives from e.g. a HTPC, like me.