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View Full Version : High bitrate 4k - x264 vs x265


YaBoyShredderson
21st February 2021, 00:13
I want to produce high quality files for archival purposes. They will also be the final product being uploaded to youtube.

Rather than let davinci resolve do the encoding, i have decided to export uncompressed and then encode that file to get the final product, and then deleting the uncompress file. I plan on doing this as davinci resolve doesnt give me a lot of options, at least not the free version.

The product will be 4k, 8 bit SDR content at either 30 or 60 fps, i havent decided, but most probably 30. While i am compressing it to save space, the quality does need to be very high, visually lossless. It needs to be good enough that you would have absolutely no qualms about encoding it again if need be, something like a 4k bluray.

X265 really starts to stretch its legs at 4k, but its also really slow, evem without using the veryslow preset, x264 is much faster, and due to my videos being sdr, wont pose a problem, but it means even higher bitrates. What should i do?

Also what crf should i use? With my preset in staxrip i use to encode my 4k blurays, i use crf 20, this gets me an average of about 18mbits. Going by the +/-6 crf rule, i think a crf 12 will give me about the same bitrate as a 4k bluray.

Asmodian
21st February 2021, 06:33
Is storage or speed the most important?

It needs to be good enough that you would have absolutely no qualms about encoding it again if need be, something like a 4k bluray.

For this use case I suggest encoding it in a method compatible with 4K bluray. You don't want to store it at a higher bitrate than a 4K bluray do you? Recompressing just to get the video compatible with hardware seems wrong.

4K bluray is a high quality very compatible option so it is a decent archival target if you are storing 4:2:0 H.264/5 video.

I would use something like x265 crf 16. 12 is excessive with x265 even for archival purposes.

A nice fast veryslow crf 12 to 14 with x264 is also a great option but then this post isn't very helpful, is it? :o

x264 would probably be a much faster workflow, do you have a dedicated encoding machine that you don't mind being busy most of the time?

YaBoyShredderson
21st February 2021, 09:20
Is storage or speed the most important?



For this use case I suggest encoding it in a method compatible with 4K bluray. You don't want to store it at a higher bitrate than a 4K bluray do you? Recompressing just to get the video compatible with hardware seems wrong.

4K bluray is a high quality very compatible option so it is a decent archival target if you are storing 4:2:0 H.264/5 video.

I would use something like x265 crf 16. 12 is excessive with x265 even for archival purposes.

A nice fast veryslow crf 12 to 14 with x264 is also a great option but then this post isn't very helpful, is it? :o

x264 would probably be a much faster workflow, do you have a dedicated encoding machine that you don't mind being busy most of the time?

4k bluray was just an example for the kind of quality im looking for, as well as a size ceiling. Not necessarily a compatible file. Yes crf 16 with x265 should be fine, 12 is a little big. X264 is very fast on my machine, so given its 8 bit SDR ill give it a try and see how the size comes out. If not, x265 it will be, thanks.

YaBoyShredderson
21st February 2021, 09:48
One last thing actually. If i do use x265, is it worth using 10bit? I use 10 bit on 1080p 8bit blurays, so i was wondering if its worth using in this case?

lansing
21st February 2021, 19:51
If you're recording gaming footages, you'll need at least 60 fps. 30 fps is unwatchable.

Any crf lower than 17 is a waste of time. Encoding in 10 bit will help on preventing banding issue if your content has a lot of flat areas. You can just try it out yourself on some motion scenes to see how the setting goes.