Super small file

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Jriker1
Posts: 17
Joined: Thu Oct 24, 2013 3:52 pm

Super small file

Post by Jriker1 »

Description of problem or question:

I am encoding a BD disk that the source file is 4k HDR10 and about 77 gigs i n size into HEVC MKV file using NVEnc with my NVidia RTX 3080 ti. I'm using CQP and used to various quality files returning different size results but this is nuts. So it's a 2 1/2 hour source and the final output with CQP 19 came out to 3.62GB. Is that even physically possible?

Using current version of HandBrake and on Windows 10.
Woodstock
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Re: Super small file

Post by Woodstock »

Without seeing the source file, it is hard to say, but... it is possible to compress that far. If the 77GB was not well compressed.

I have seen 10:1 compression on x264 file without major work, but those were anime features that were not well compressed to start with.
Jriker1
Posts: 17
Joined: Thu Oct 24, 2013 3:52 pm

Re: Super small file

Post by Jriker1 »

Obviously not going to be able to share the file but can say the source bitrate averages 56mb/s and the output file is only like 6mb/s. Was my understanding a HEVC CQP 19 or lower was nearing lossless visually anyway. I know I can take older footage, remastered 4k, that has a lot of grain and the resulting file could be 40gigs and a cleaner file will be a lot smaller however that's nuts. Not sure if OK to do so but I own the Fantastic Beasts The Secrets of Dumbledore BluRay and that's what I end up with. Oddly I think the file is very clean and there isn't a lot of motion but just seems odd.
Woodstock
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Re: Super small file

Post by Woodstock »

Nearly lossless is a vague term, really.

I don't know what your source is like, but I do know what some of mine have been like. An animated title has vast areas of relative sameness that can compress well, but a non-animated title can have lots of detail that doesn't. ~20:1 at the same output size implies a LOT of "sameness" that can be compressed out, OR that something was not right in the compression.

Have you compared the source and compressed result? Does it look "almost identical" to the original, or can you see lots of compression issues?

There have been complaints about the Nvidia compression not meeting the same specifications as the software encoder, and it is possible you have tripped over one of them. I have a system when the software vs. hardware compression showed that the "equivalent" compression wasn't worth the 20x reduction in speed the hardware had, so I just let that system cook on software, and use a different system to queue things up.

It is certainly a problem that the hardware and software encoding methods are not identical in output, though.
mduell
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Re: Super small file

Post by mduell »

Sure it's possible; depends on the source content, your settings, and your own personal preferences/acuity.
Lostless
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Re: Super small file

Post by Lostless »

It is entirely possible. On Blu-ray or 4k blue-ray, the studios have tons of room to just throw the highest bit rate without care to give every frame the best possible quality. Even though that high of bit rate is not needed to maintain most of the image quality. It’s over kill on purpose.
Handbrake on the on the other hand has a different agenda. Make the smallest possible file size, while looking as close to the original content as possible. It uses tricks to throw out as much data to maintain a version that looks almost identical to the original content to our eyes. So with a blu-rays overkill bit rate, handbrake has a lot to work with to bring the file size down.
Jriker1
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Joined: Thu Oct 24, 2013 3:52 pm

Re: Super small file

Post by Jriker1 »

Thanks for the replies. Below are dropbox links with an image of a frame of the original, one with CQP19 and one with CQP16. Not sure if anyone sees a difference

Original: https://www.dropbox.com/s/ha1nus7najvyx ... l.png?dl=0
CQP 19: https://www.dropbox.com/s/tokakucqb3fgb ... 9.png?dl=0
CQP 16: https://www.dropbox.com/s/1ad6ve96eqt17 ... 6.png?dl=0
mduell
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Re: Super small fileOe

Post by mduell »

One frame is not an appropriate way to compare encodes, since it's not how you watch a video.
Jriker1
Posts: 17
Joined: Thu Oct 24, 2013 3:52 pm

Re: Super small file

Post by Jriker1 »

Always have a hard time comparing multiple videos, one at a time or otherwise. In this case it's a Dolby Vision video so the source is kind of washed out on my PC.
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