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H265 crf


scb99

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scb99

In general I'm got a great fan of transcoding to save space, but I decided to do a batch transcode of a bunch of my "tier 2" material from H264 to H265 because I can save a shedload of space that way 

I've been using a crf of 28, and tbh it's all looking fine to me.

But I just thought I'd quickly ask here, if anyone has any comments on this, or if there are any edge cases I should watch out for.

Cheers and Thanks, Steve

 

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Hi, sounds like it should be fine. You might see additional transcoding though when playing the hevc if not supported by your client devices.

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scb99

@Luke OK thanks for the feedback, it's good to have a bit of reassurance from the experts, sure I understand about the possible playback transcoding

Cheers

 

PS Any other feedback from anyone else who's actually done the same would be very welcome.

 

 

Edited by scb99
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Deathsquirrel

There is no one setting that works for all types of media that produces good results while saving any significant space.  That's why I stopped bothering trying to shrink my video files and just bought more drives.

You'll want to check your content  carefully.  I especially recommend checking dark action sequences on whatever your best playback device is.  Those often look dreadful after an aggressive reencode.

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scb99

Thanks @Deathsquirrel I will do that.

In principle I always thought the same, but it's not the main storage it's the backup system that keeps needing shuffling round and I've just found it's eating more and more of my time. So I looked around and I realised there's a bunch of 8GB interview extras and suchlike, so I set up a simple batch job (powershell) scouring round my network for these and I found I can save a shedload of space - and hence my time - on what you might call second tier stuff like that. I'll def watch out for what you say (dark / motion), I was afraid it might not be "one setting fits all". Cheers and thanks. 

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  • 4 weeks later...
RanmaCanada

A CRF of 28 is rather high.  I use CRF 20 for TV shows and 17-19 for movies pending on their complexity.  Here is some information you could use to make things more transparent.

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scb99

Hey @RammaCanada that's a very interesting spreadsheet. Thanks a lot! 

Yes the 28 was just on these static "talking heads" extras where I wasn't too bothered about the quality, but it all seemed fine anyway.

In the meantime I've also done one TV series where they had put material that was really only worth SD into HD, so with a bit of experimentation I compressed it back to what it would have been in SD anyway.

There's a lot I have to learn about ffmpeg (and H265), and now I'm trying to do that slowly...

Thanks again

 

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rbjtech

Just to add, that AV1 is around the corner - it's rapidly gaining support with all the big players and will likely replace hevc as it's free to license and even better at lower bitrates.   The only current downside is encoding speed which is very slow, even vs hevc but hardware encoders are in the works.

So, if you are desperate for space, then hevc is probably, at this time, the only realistic option - but if you can wait ~6 months, I would say that AV1 would be a better longer term investment in your encoding time.

All my non 4k media is still h264 - I've thought about the transition to h265 many times, but vs the power and effort to do it, as has been said above, it's cheaper/quicker to just buy bigger storage.  AV1 may change that assuming the encoding can be done in hardware with the latest Intel GPU's for example.. 

What to do ... 🙄

Edited by rbjtech
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12 hours ago, rbjtech said:

it's cheaper/quicker to just buy bigger storage

The quicker I understand... But why cheaper? Disks and extra hardware doesn't make it cheaper, surely?

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rbjtech
4 hours ago, kaj said:

The quicker I understand... But why cheaper? Disks and extra hardware doesn't make it cheaper, surely?

The cost of electricity to convert lets say 8Tb worth of h264 to another codec @ 100% cpu for that entire time will be significant and something to factor into the equation.

'Cheaper' - maybe ?, that's a fair enough comment - that all depends on the cost of your electricity in your region I guess.

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Buying enough disks, presumably large and running in a redundant array, the additional hardware to run the new array etc etc, would surely cover several decades of CPU conversion cycles...

I definitely agree it's way quicker to just buy new storage, and it wasn't even your comment, rather several others that keep saying the same quicker and cheaper mantra... And the new disks are going to consume more power too... This is just a light hearted answer, not meant to be argumentative or in any way inflammatory 😀

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scb99

I do my offline backups in blocks, and it was easier for me to save a bit of space than to create a whole new backup cycle and reorg all my offline media. (I keep 3 copies of everything, 1 online, 1 remote, 1 offline)

I mean it‘s easy to say just keep adding space, but there‘s a lot of admin around that.

Edited by scb99
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Q-Droid
On 4/28/2022 at 12:39 PM, RanmaCanada said:

A CRF of 28 is rather high.  I use CRF 20 for TV shows and 17-19 for movies pending on their complexity.  Here is some information you could use to make things more transparent.

The CRF range of values is different between x264 and x265. A CRF of 28 is the default value for x265 while 23 is default for x264, they are visually equivalent.

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RanmaCanada
6 hours ago, Q-Droid said:

The CRF range of values is different between x264 and x265. A CRF of 28 is the default value for x265 while 23 is default for x264, they are visually equivalent.

No they aren't as it all depends on the content that is being encoded.  I haven't spent the last 2 decades on doom9 for nothing.  But if you think default settings are "good enough", that's your problem. 

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Q-Droid
13 minutes ago, RanmaCanada said:

No they aren't as it all depends on the content that is being encoded.  I haven't spent the last 2 decades on doom9 for nothing.  But if you think default settings are "good enough", that's your problem. 

No what I'm saying. I'm not claiming that the defaults are great but won't say they aren't good enough, that is a matter of preference. But using a CRF of 17-19 for x265 is much different than the same value for x264 and more work as well. My post was to clear things up for people used to x264 with CRF of 23 as a reference that for x265 the equivalent is 28.  That's all. The rest is up to each person to test and decide.

 

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rbjtech
On 30/04/2022 at 11:49, kaj said:

Buying enough disks, presumably large and running in a redundant array, the additional hardware to run the new array etc etc, would surely cover several decades of CPU conversion cycles...

I definitely agree it's way quicker to just buy new storage, and it wasn't even your comment, rather several others that keep saying the same quicker and cheaper mantra... And the new disks are going to consume more power too... This is just a light hearted answer, not meant to be argumentative or in any way inflammatory 😀

Hi @kaj - all good here ;) 

The way I upgrade capacity, consumes no additional power as I upgrade the disk capacity.  ie I upgrade a 4Tb disk with an 8Tb disk - thus I get a 4Tb extra capacity for no extra power requirements.  The old 4Tb disk then get's re-purposed as an offline backup. (I don't run redundancy on media - I don't see the need to - but that's another debate .. haha). 

 

 

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kaj

yes, this is/was the way I was thinking of going, swapping to higher capacity disks. i started to look at prices here in Oz, and surprisingly it seems it would be cheaper to keep my existing NAS and add an expansion unit.

I have, presently, a Synology 918+ with 4x8TB disks.

Cost of upgrading to 16TB disks is approx. 4x$800 = $3200

Cost of DX517 expansion unit $750. Cost of 4x8TB disks is approx 4x$400 = $1600, total cost $2350

Luckily I'm not a completely quality freak, so I'm happy having most TV shows in 720p x265, ditto movies, which does help slow down my present disks filling up...

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