Quality vrs Size - MKV - HandBrake quality option best solution?

[StumpedTechy]

Okay I have a LARGE number of MKV files that I have already ripped from Blu-rays. I have them all on a NAS (this is over 300 blu-rays I own that I wanted to be able to stream around my house). The problem is my NAS is almost out of space. Of course the offending media is the Blu-rays, as my DVD rips are only a few gig in size, but are also not 1080p. A lot of my Blu-ray rips are in the 35GB in size range because I did a straight high quality rip (?or should I say conversion?)with no loss. So now I have all my movies mpeg 4 in mkv containers with high quality DTS sound in them. With space now being an issue, I have to decide the extent I want to compress them down.

I have decided that compressing them down about 1/3rd the size would be good and give me a couple more years of Blu-ray collecting without having to get a new NAS.

What I came across to use was HandBrake and use the quality option. This seems perfect for me because it will process the MKV right as it is and put it back into a smaller MKV with the same mpeg 4 and there isn't worry about conversions or my streaming devices. HandBrake has an option that is Quality which is under the tab labeled "Video" and the top right option. If you set it to 0 there is no drop from the original media format it goes from 0 to 51. If I do a 0 it takes exactly the same space. So the question I have is each slider option 2% loss? If it is 2% loss at what point does the quality become non HD compliant if its a straight from Blu-ray rip? 20? 25? I noticed it said 18-20 for standard definition and 20-23 for high definition and I am confused how you go to a higher number for high definition if that means more loss? Is it just that with HD it can drop a bit more and still be playable quality because of the added information and amount of data?

When I ran my 35 GB file through it at quality 20 RF it came out at 11.4G. This is even smaller than I had wanted. I am thinking maybe 10 RF would be the magical number and keep it at about 20 GB. Is 10RF still too bloated and would I really need that data vrs the TV we are watching it on? Basically I have a 1080p 60mhz 65 inch TV that I do streaming to via an HDMI WDTVLive and I want this to still be as great as quality as I can with also trying to save a bit more space on my NAS. Is the above the best way to address creating the space on the NAS? Is there a better way than the above option that anyone can recommend?

[Kerry56]

16 to 18 is what most would consider the start of the "transparent" conversions, or in other words, a quality level not easily distinguished from the original when playing. Close examination, scene by scene and frame by frame will show some differences of course. CRF level is only part of the equation, though an important one. There are other adjustments. I use VidCoder (a different GUI for Handbrake), and for Blu-ray converted to MKV, I normally use Slow encoding, High profile, 4.1 Level, Constant Framerate and CRF set to 18.

VidCoder can be set to encode to a specific file size if you prefer to do that instead of using the CRF control. If doing this, I'd do a two-pass encode.

[nic2k4]

Only you can decide what quality you can live with, I can't imagine what it would be like on your 65" TV. OTH, how long did it take to convert with 10RF? Now multiply that by the number of files to process. Is the work involved worth it? Maybe you can just add another NAS instead of replacing the old one.

[_Al_]

I noticed it said 18-20 for standard definition and 20-23 for high definition and I am confused how you go to a higher number for high definition if that means more loss? Is it just that with HD it can drop a bit more and still be playable quality because of the added information and amount of data?

SD resolution will be blown up on your big screen, so everything will be upscaled, including nasty artifacts, hence that approuch in that manual for SD resolution, to just keep heads up, and make sure quality is always set a bit higher.

[jagabo]

RF 10 may create files bigger than your Blu-ray sources. If you didn't know which was which, you probably couldn't say which was better, the original or a RF=12 encoding, even looking at enlarged still frames.

[StumpedTechy]

nic2k4 time to convert is no problem I have access to 5 computers and the fast ones are only about 3 hours for each movie its not really a matter of processing time its about the time I need to spend so if I can automate it letting it sit processing on a computer that isn't used is fine. _Al_ Thanks I'll keep that in mind. jagabo your confusing me your saying original is RF 12? Then why does HandBrake indicate 0 is lossless? Shouldn't it say RF 12 is lossless and higher is enhanced somehow? Kerry56 I'll take a look at that thanks for the valuable information.

[jagabo]

I'm saying that your original Blu-ray proably has a bitrate similar that which RF 12 will produce (it will vary with different sources). And that RF 12 will give you a picture so similar to the source that you won't be able to tell the difference. Indeed RF 0 is lossless -- but your video will balloon up in size several fold if you use that.

The process of recompressing a video involves first decompressing it to uncompressed frames. That causes it to balloon up in size about 20 fold. You then compress those frames with the new compression scheme. If that new compression is a lossy codec you will get some loss of quality. If you use good enough settings that loss will not be noticeable under normal viewing conditions. Lossless codecs typically can only reduce the size to 1/2 or 1/3 the size of the uncompressed source.

[smrpix]

I have access to 5 computers and the fast ones are only about 3 hours for each movie

(this is over 300 blu-rays I own that I wanted to be able to stream around my house).

You want to spend 900 hours on this project instead of adding more disk space? At $1 an hour you could add roughly 30TB.

[El Heggunte]

^ Yes, 3 hours x 300 discs = 37.5 days

u_u

[hello_hello]

When I ran my 35 GB file through it at quality 20 RF it came out at 11.4G. This is even smaller than I had wanted. I am thinking maybe 10 RF would be the magical number and keep it at about 20 GB. Is 10RF still too bloated and would I really need that data vrs the TV we are watching it on?

Don't take one single encode as being typical. The file sizes vary quite a bit for a given CRF value. I use CRF20 for 1080p myself. That seems to give me average file sizes of around 8GB (keeping 5.1ch AC3 audio). Much of the time I resize down to 900p or 720p because a lot of Bluray video doesn't have 1080p worth of picture detail (and I've done lots of comparing) but that aside, for 720p I tend to go with CRF18. The CRF value is all personal choice though. After you've run a few encodes you'll settle on CRF values which give you file sizes you're happy with..... on average.

One frustrating factor for me is the quality of Bluray video often tends to be some flavour of incredibly average to begin with. I can't wait for 4K 's worth of crap. I spend more time fussing around with filtering than worrying about CRF values these days.

[fritzi93]

Keep in mind that when the Blu-Ray spec was finalized, MPEG2 was the favored codec, though it also includes AVC (H.264) and the proprietary VC-1. The latter two are perhaps 3x (?) as efficient as MPEG2. Also recall there was a format war at launch with HD-DVD, and Sony had the selling point of more capacity. (Though what ensured Sony would prevail was probably the supposedly unbreakable copy-protection).

Many of the first Blu-Ray releases were MPEG2, and they needed the BD50 capacity. Later releases in AVC and VC-1, not so much, although there was plenty of space for crap extras. Remember that selling point? How many here care for fancy menus and *most* extras?

The point is, IMO, that damn near any *main movie* Blu-Ray you care to name could be put on a BD25 (single layer) using H.264 and be indistinguishable from the original.

Then there's the question of what can you actually see on your display during normal viewing? I have a 1080p 70" Sharp LED/LCD, not reference quality, but decent enough. Viewing distance ~ 8 feet, at which supposedly you get maximum benefit from the resolution and display size.

I early on settled on crf 20 as acceptable quality at smallest file sizes (and superfluous audio streams removed). If I had to do them over, I think I'd go with crf 18. I can just tell the difference between original and crf 20 if I watch intently (again, normal viewing, mind you). I may get around to it, but that's gonna be a lot of encoding.

Anyway, all good answers above. If you want to go to the trouble of doing everything over, I don't think you could do better than Kerry's recommendation of crf 16-18 in the first reply to this thread. Though there's also much to be said in favor of just getting more hard drive space.

Good luck.

[jagabo]

In the CRF 18 range the biggest problem to watch for with x264 is posterization in dark areas. You can get around that by using aq-mode 2 and turning aq-strength up to 1.8 or so. That will bump the bitrate up, especially with grainy sources. Or you can use a lower CRF which will also increase the bitrate.

[fritzi93]

In the CRF 18 range the biggest problem to watch for with x264 is posterization in dark areas. You can get around that by using aq-mode 2 and turning aq-strength up to 1.8 or so. That will bump the bitrate up, especially with grainy sources. Or you can use a lower CRF which will also increase the bitrate.

Yeah, I just came back to edit my post and say that you can tell by watching the dark areas. Beat me to it.