Suspiciously small file sizes with h.265

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
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planetmarshall
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Suspiciously small file sizes with h.265

Post by planetmarshall » Mon Nov 12, 2018 1:15 pm

I ripped a couple of UHD BluRay films using MakeMKV - Bladerunner 2049 and 2001: A Space Odyssey. I stripped out all but the English audio tracks, and the resulting file sizes were on the order of about 60 Gb.

I then re-encoded these files using H.265 at the source resolution (but auto-cropped), and with pass-thru audio at a CRF of 22. On my ancient laptop it took about a day or so per file.

The resulting file sizes were around the 10 Gb mark. This is far less than I expected (and smaller than some of my h.264 1080p videos), but on inspection they *appear* to be full 4k videos, of the original length, with the original audio streams intact.

You might wonder what I'm complaining about, given the quality on my 50" TV seems indistinguishable from the original rip, it just seems pretty unlikely - aren't UHD blu-rays *already* encoded with h.265?

Is there a way to use ffmpeg to dump the encoding parameters? Maybe I've missed something obvious.

Cheers,
Andrew.

rollin_eng
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Re: Suspiciously small file sizes with h.265

Post by rollin_eng » Mon Nov 12, 2018 1:55 pm

Could you please post your HB logs, instructions can be found here:

https://handbrake.fr/docs/en/latest/hel ... y-log.html

Woodstock
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Re: Suspiciously small file sizes with h.265

Post by Woodstock » Mon Nov 12, 2018 3:32 pm

Both Bluray and UHD disks are compressed "enough" to fit their respective media. When you have the space, it really doesn't pay to compress more than necessary to fit in that space. If the disk author needed to fit a 4 hour film on a UHD disk, they could chose to use a far more aggressive, slower compression than most of us would do, but that isn't necessary to fit a 1:40 film on the media.

mduell
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Re: Suspiciously small file sizes with h.265

Post by mduell » Mon Nov 12, 2018 4:40 pm

Hmm, interesting non-general question about a specific encode. If only we knew more about what was actually involved.

musicvid
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Re: Suspiciously small file sizes with h.265

Post by musicvid » Tue Nov 13, 2018 1:36 am

If your file sizes with x265 seem small, the solution is simple -- encode with x264.
That is not a flippant remark; at 8 bit 420, uhd doesn't really need the extra compression, and it will go a LOT FASTER!

planetmarshall
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Re: Suspiciously small file sizes with h.265

Post by planetmarshall » Wed Nov 14, 2018 9:10 am

musicvid wrote:
Tue Nov 13, 2018 1:36 am
If your file sizes with x265 seem small, the solution is simple -- encode with x264.
That is not a flippant remark; at 8 bit 420, uhd doesn't really need the extra compression, and it will go a LOT FASTER!
That's actually not a bad idea, particularly since my HTPC supports hardware decoding of h.264. I want to do a bit of investigation first, though.

musicvid
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Re: Suspiciously small file sizes with h.265

Post by musicvid » Wed Nov 14, 2018 11:23 am

Sure.
x265 will get you smaller files at the same quality as optimized x264.
The time savings of encoding x264 is huge.
Since storage is cheap, you should not need x265 for 4K until we are delivering HDR.

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