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View Full Version : Came from 2016, updates on hevc? on grainy sources compared to h264


bxyhxyh
26th September 2021, 09:43
I'm pretty sure HEVC got much more tuned now.
I could test it myself. But now, i'm not really into video stuffs, I'm just checking it out, out of curiousity.

1. On grainy or very detailed sources, it wasn't really as good as h264 even on same bitrate at the time. Did that get changed?

2. On small resolution sources H264 seemed to perform better due to small block sizes at that time. 720p and lower. Did this get changed as well?

rwill
26th September 2021, 11:47
I'm pretty sure HEVC got much more tuned now.
I could test it myself. But now, i'm not really into video stuffs, I'm just checking it out, out of curiousity.

1. On grainy or very detailed sources, it wasn't really as good as h264 even on same bitrate at the time. Did that get changed?

2. On small resolution sources H264 seemed to perform better due to small block sizes at that time. 720p and lower. Did this get changed as well?

HEVC as a lossy video format has the potential for having higher compression efficiency than AVC in the use cases AVC covers, although I am not sure if this is true for interlaced.

If a specific HEVC encoder is better than, lets say, x264 for some use case you pick depends on the HEVC encoder implementation.

ReinerSchweinlin
26th September 2021, 14:59
1. On grainy or very detailed sources, it wasn't really as good as h264 even on same bitrate at the time. Did that get changed?

There is a tuning switch "-grain" which helps in that regard. In my findings, the bitrate went up quite a bit (which seems logical) when doing a fixed Q Encode and leave everything else the same way. But it helped especially for small resolutions to keep the details.

I did some comparisons a while ago with x264 and x265 for DVD Backups I had on my NAS and concluded, that x264 "very slow" did the job better for DVD resolutions...

Blue_MiSfit
28th September 2021, 00:37
I'm not too surprised that for the "transparent DVD backup" use case the benefit of x265 was tough to see over x264. Push the bitrate very low and you'll see the benefit, even with SD! However, HEVC really shines at HD and UHD resolutions.

benwaggoner
29th September 2021, 20:05
x265 is much better at grainy content in default settings than it was in 2016, but still far from perfect. There's not a --tune film equivalent preset to optimize for light-moderate grain. And --tune grain is pretty much a bitrate blunderbuss that drives up bitrate a lot for non-grainy content.

To get good results at lower resolution, try --tu-intra 4 --tu-inter 4, which will recurse down to 4x4 blocks like H.264 uses by default. For somewhat grainy content, --nr-inter 100 can help get grain to be less "swirly" and use fewer bits. If there's a lot of text or fine lines, --tskip can help, but you'll not see much of that with DVD sources. You'll want --no-sao as well for detail retention.

But hey, if x264 works great for you, no essential reason to switch. For low resolution grainy content, the bitrate savings of x265 over x264 are a lot smaller than with higher resolutions and cleaner content.

rbauer
30th September 2021, 23:08
To get good results at lower resolution, try --tu-intra 4 --tu-inter 4, which will recurse down to 4x4 blocks like H.264 uses by default. For somewhat grainy content, --nr-inter 100 can help get grain to be less "swirly" and use fewer bits. If there's a lot of text or fine lines, --tskip can help, but you'll not see much of that with DVD sources. You'll want --no-sao as well for detail retention.

That's all really very interesting. :eek:

If I am allowed a question: I would like to greatly reduce the size of the files but at the same time getting the best quality for the compression used.

The content of video sources: online math/statistics/programming video lessons (with wacom's tablet stylus, power point slides, digital note-taking, digital handwriting, etc.).

I usually use the x265's "very slow" preset (handbrake) at constant quality ~34.
Under the same conditions mentioned above, would the following parameters help to increase the quality (without bitrate increase) a little?

--dynamic-refine --tu-intra 4 --tu-inter 4 --tskip



many thanks.

RanmaCanada
2nd October 2021, 03:50
I would honestly say if you want to know the current state, if you own Alien, encode it and see if it can finally be smaller than the original. It was suggested here 2-3 years ago as a source for grain as it has a LOT of film grain, and at that time, the encode ended up being larger than the source. Anything that works on that, should work on any source.