Nvidia HEVC very low quality?

[Jiehfeng]

Why are my output files in such low quality when I use HEVC? A 1GB file becomes like 20MB and the quality is terrible. Here's how the configuration looks, haven't touched anything:



How can I fix this?

[sophisticles]

Why are my output files in such low quality when I use HEVC? A 1GB file becomes like 20MB and the quality is terrible. Here's how the configuration looks, haven't touched anything:



How can I fix this?

I'm really shocked that when you take a 1Gb file and use 50 times less bit rate the quality is terrible.

Shocked, I tell you.

[Jiehfeng]

Why are my output files in such low quality when I use HEVC? A 1GB file becomes like 20MB and the quality is terrible. Here's how the configuration looks, haven't touched anything:



How can I fix this?

I'm really shocked that when you take a 1Gb file and use 50 times less bit rate the quality is terrible.

Shocked, I tell you.

You don't have to be so sarcastic and condescending just because I don't know much about these things. :/

And I thought whatever is greyed out doesn't count.

[jagabo]

I don't know what software you're using but what settings does the High Quality preset use? Are you scaling or otherwise filtering the video? What are the properties of the source? Uncompressed? Losslessly compressed? HEVC? Frame size? Frame rate? Running time? Use MediaInfo in View -> Text mode to get the properties of your source and HEVC video. Post them here.

[poisondeathray]

Try changing the settings, especially the "controlled by preset" drop down box . That might unlock some of the other options instead of "greyed" out

[Jiehfeng]

I don't know what software you're using but what settings does the High Quality preset use? Are you scaling or otherwise filtering the video? What are the properties of the source? Uncompressed? Losslessly compressed? HEVC? Frame size? Frame rate? Running time? Use MediaInfo in View -> Text mode to get the properties of your source and HEVC video. Post them here.

I'm using Avidemux, thought I'd try this relatively new Nvidia encoder as I've got a Nvidia GPU.
What I did was I loaded the video to Avidemux, changed the Video setting from Copy to Nvidia HEVC, and just exported it from there. When I went back to check the settings, it's what it looks like in the screenshot in the OP. I can't change the bitrate or anything as it is greyed out, the only things I can change in the settings are these:



Here's the MediaInfo you requested:

[Jiehfeng]

Try changing the settings, especially the "controlled by preset" drop down box . That might unlock some of the other options instead of "greyed" out

Ah that's it, it does allow me to change it now. Thanks! I should've tried them even if I didn't know what it was.



So if I want similar quality I just match the bitrate right? Sounds easy enough, thanks again.

EDIT:
Nope, still very low file size and quality, the resulting bitrate is lower than what I seemed to have set it as, if I didn't make any mistakes that is.

copied this (the total bitrate):

With those settings I got this:


And for some reason MediaInfo shows a different higher bitrate:

What am I doing wrong?

[poisondeathray]

Add some b-frames , 2 or more (maximum consecutive b-frames)
Increase the GOP size to 300(for 5 sec) or 600 (for 10sec) at 60FPS
Use Variable Bitrate, and 2 pass mode


Constant quality mode should be ok too, and you just adjust the quality value (unpredictable bitrates and filesizes, dependent on source characteristics)

[Jiehfeng]

Add some b-frames , 2 or more (maximum consecutive b-frames)
Increase the GOP size to 300(for 5 sec) or 600 (for 10sec) at 60FPS
Use Variable Bitrate, and 2 pass mode


Constant quality mode should be ok too, and you just adjust the quality value (unpredictable bitrates and filesizes, dependent on source characteristics)

Could you maybe explain what those are please, in layman's terms?
I did as you said but I can't set the GOP size to 300, the max it goes is 250.
I'm not sure what max bitrate does, how should I calculate that, or the normal bitrate setting?
I'll try the quality mode if I can't figure out the more manual approaches.

This is what I did so far, I'll test to see what I get:



EDIT: With those settings the exporting happens immediately and the file is a broken 258 byte file. What's wrong in the settings?

[poisondeathray]

What card do you have ? Older ones did not support b-frames for HEVC, or maybe you need to update driver

b-frames improve compression efficiency at typical bitrate ranges (They are bidirectionally predicted frames), with diminishing returns (adding more than 2-3 helps less and less) unless using very low bitrates

max GOP size also compression efficiency at typical bitrate ranges also with diminishing returns , at the expense of seek latency (slower to navigate) . A typical high compression file might use 5-10 sec keyframe intervals . 10 seconds for 60fps is 600

Max bitrate is a restriction, that you should not use (it only decreases quality), unless some device or playback scenario requires it (some devices "choke" on bitrate peaks, or buffer underruns) . A general guideline if you can't disable it is to use some large value like 2-5x the average bitrate, or use the value that your playback scenario or device requires (some devices have presets or certain required values)

[Jiehfeng]

What card do you have ? Older ones did not support b-frames for HEVC, or maybe you need to update driver

b-frames improve compression efficiency at typical bitrate ranges (They are bidirectionally predicted frames), with diminishing returns (adding more than 2-3 helps less and less) unless using very low bitrates

max GOP size also compression efficiency at typical bitrate ranges also with diminishing returns , at the expense of seek latency (slower to navigate) . A typical high compression file might use 5-10 sec keyframe intervals . 10 seconds for 60fps is 600

Max bitrate is a restriction, that you should not use (it only decreases quality), unless some device or playback scenario requires it. A general guideline if you can't disable it is to use some large value like 2-5x the average bitrate

Thanks a lot for the explanations!
So is 250 for the GOP size alright? It's not allowing me to go any higher. I set the max bit rate to 40000kbps and it still exports immediately with a broken file.

I have the RTX 3080, got new drivers (September 28th) but haven't got to the very latest. Is it because it's a newer card?

[poisondeathray]

250 should be ok; it won't negatively affect it that much

RTX 3080 supports HEVC b-frames (pascal did not - RTX 10xx cards)

Might be driver issue, or something might be broken in avidemux implementation, I don't know. You can check avidemux forum, or try other software

[Jiehfeng]

250 should be ok; it won't negatively affect it that much

RTX 3080 supports HEVC b-frames (pascal did not - RTX 10xx cards)

Might be driver issue, or something might be broken in avidemux implementation, I don't know. You can check avidemux forum, or try other software

Thank you, I will post on their forums.

[jagabo]

So you requested 26944 Kbps but the encoder delivered only 252 Kbps? Something is going wrong with the encoding. Try a different program. I believe Handbrake supports NVEnc.

[LigH.de]

Selur's Hybrid may help as well.

[Jiehfeng]

So you requested 26944 Kbps but the encoder delivered only 252 Kbps? Something is going wrong with the encoding. Try a different program. I believe Handbrake supports NVEnc.

Selur's Hybrid may help as well.

Thank you, I will try those. A mod in the avidemux forum is also seeing to my log to find out what's going on.

[sophisticles]

You don't have to be so sarcastic and condescending just because I don't know much about these things. :/

I don't have to be, but I do enjoy it so much.