Has anyone used X264 to produce a replicated BD title?

[shon3i]

Originally Posted by kolak

H264 specification is one thing and Blu-ray one is another. It's almost obvious that BD one is going to have more restrictions.

Agree, but one thing is for sure, that for 1080p is max 4 ref (according both H264 or Blu-Ray specs) and for 720p is 6 refs (according Blu-Ray specs).

Originally Posted by kolak

Another thing is that quite often pro encoders have even bigger limitation than BD spec.

Andrew

Better leave some room for errors

Originally Posted by Lyris

I've been trying Mainconcept Reference and while not quite at the level of X264's quality,

I don't know why but Mainconcept Reference use very restricted version of their SDK, which have much more tweakable options. Only Sonic Cinevison use most advanced options from Mainconcept and can be compared with the x264, and may be approximate, even in some situations better. Mainconcept CLI use all features but

Originally Posted by Lyris

what it's producing is at least slightly better than the encodes I see on retail BDs

Maybe hardware encoders?

[Lyris]

Do you get better results with Mainconcept at L4.1 than with x264 at L4.0?

No. x264 still looks better despite having around half the bit rate.

[Chengbin]

Originally Posted by Lyris

No. x264 still looks better despite having around half the bit rate.

I'm amazed.

This begs the question, how hard can adding slice support be? x264 used to support slices, but was removed because of a better multithreading technique. Is the old slice algorithm is bad?

[shon3i]

Old method can hurt more quality, but i aslo think that no one use more than 4 slices, without some special reason. Anyway if some one use more slices, quality shouldn't drop so drastically.

New metod is indeed better for decoding on modern (multi core) procesors and better for encoding because drop in quality are very, very small. But is also have only effect when is decoded with decoder which support that metod (ffdshow-mt, coreavc). The only thing which i can't understand is why we need this because we have DXVA, CUDA, which can decode Blu-Ray video normaly, and slices which are almost suported by every decoder (HW/SW), and we have enough powerfull processors to decode in single core 1080p video.

[Chengbin]

Originally Posted by shon3i

Old method can hurt more quality, but i aslo think that no one use more than 4 slices, without some special reason. Anyway if some one use more slices, quality shouldn't drop so drastically.

We all know slices hurt quality. But even with slices, x264 is still a lot better than commercial encoders since it doesn't hurt too badly. Unless there is compatibility issues with current features, why not just put the old code back and call it a day for Blu-ray compatibility? You can always improve it later.

[shon3i]

Originally Posted by shon3i

why not just put the old code back and call it a day for Blu-ray compatibility? You can always improve it later.

Exactly, I tried a few times to convince the same, in the past, but no one was interested.

[Dark Shikari]

Originally Posted by shon3i

Exactly, I tried a few times to convince the same, in the past, but no one was interested.

You can't "put the old code back"; that would be far more difficult than just writing support anew.

[plonk420]

will this be on x264's Summer of Code 2010 if it's not added by then?

[Dark Shikari]

Originally Posted by Chengbin

Well, at least the work is done already. You just have to "trace" it, which I believe it is much easier than writing something new.

"Trace" the complete overhaul of most of the frame handling code, which will be further rewritten by threaded slicetype? Are you insane?

[shon3i]

Originally Posted by Dark Shikari

You can't "put the old code back"; that would be far more difficult than just writing support anew.

True, but for now I am satisfied with the fact that the 4.0 level does not require slices, because i backup my blu-rays to BD-5/9 media for now.

[Lyris]

OK, so now I've tested a bunch of encoders. The bitrates used for all of the tests were 35mbps average, 38mbps peak, except for X264 Level 4, which was tested at 20mbps due to the AVC Level 4 constraints. In brief:

1. X264: best quality, even at Level 4, but I can't get it to play (perhaps I have the wrong settings).

2. Mainconcept Reference: very, very, very good quality at these bitrates. It doesn't retain the high frequency grain as well as X264, but it still produces what is, in my opinion, an excellent result at the bitrates I'll be using it at. Certainly, it looks better compression-wise than just about every BD title that I've bought. I have burned discs using the trial version of Netblender DoStudio and they play back in all of the BD players I have here (Sony PS3, Panasonic BD35, Oppo BDP83, and a ridiculously expensive Denon A1). Slowest encoder of the bunch (with everything set to highest quality on 2pass): 0.7fps on a 2.8ghz Quad core.

Looking at MCR's output and judging it on its own merits, it looks fantastic. Only when you compare it to the source (and indeed to x264) do I start seeing minor flaws.

3. Netblender Dostudio Encoder: quality is not acceptable by videophile standards, but plays back fine. EDIT: turns out I'm experiencing a bug with the encoder, the poor quality is NOT the intended operation. Netblender are investigating. Fastest of the software-only encoders. Only accepts QuickTime input (d'oh... I'm very much a Windows guy. I can't live without AviSynth).

4. CodecSys CE-10. This is the one that uses a LAN-connected Playstation3 to accelerate encoding. I was getting around 6-8fps with the "Fine" mode. However, the quality is not good enough. Some frames in each GOP (presumably I frames) look excellent, sometimes even slightly better than x264, but things fall apart afterwards into compression artefacts (this is using the company's recommended BD-compliant settings). Most troublesome of all, the 4 slices in the frame are actually often VISIBLE in my test encodings! That is, you can actually see 4 clearly marked sections of the picture. No dice.

In short, I have a very good feeling about the Mainconcept Reference Encoder and hope to see its output pass verification. It's not quite up to X264's standards - but what is? - and it hopefully makes up for that in terms of compatibility with the BD spec.

[Dark Shikari]

Originally Posted by Lyris

OK, so now I've tested a bunch of encoders. The bitrates used for all of the tests were 35mbps average, 38mbps peak, except for X264 Level 4, which was tested at 20mbps due to the AVC Level 4 constraints. In brief:

1. X264: best quality, even at Level 4, but I can't get it to play (perhaps I have the wrong settings).

Are you using the NAL-HRD patch? That's necessary for compliance.

[Lyris]

I am not. I'll take a look at the patches thread and try to figure that out.

Some comparisons. Images are PNGs (OK, overkill I know), and are about 5mb each.

http://lyris-lite.net/avc/squirrel.png

http://lyris-lite.net/avc/trap.png

http://lyris-lite.net/avc/overhead.png

http://lyris-lite.net/avc/fur1.png (I frame? The Codecsys encoder looks great here)...

http://lyris-lite.net/avc/fur2.png ...(but turns to mush in the next frames).

http://lyris-lite.net/avc/slice.jpg - JPEG image showing visible slices seen on the CodecSys output.

[kolak]

Originally Posted by Lyris

In short, I have a very good feeling about the Mainconcept Reference Encoder and hope to see its output pass verification. It's not quite up to X264's standards - but what is? - and it hopefully makes up for that in terms of compatibility with the BD spec.

Cinevision can at least match x264 or even produce better results for grainy sources, but I like quality from the latest version of x264.
Some features of Mainconcept's SDK can be found only in Cinevision and they work quite well.

Andrew

[shon3i]

Originally Posted by Lyris

In short, I have a very good feeling about the Mainconcept Reference Encoder

Too bad you don't have access to sonic cinevision, which have advamced features of Mainconcept such as Grain optimization, several levels of AQ (including Dark AQ).

Originally Posted by Lyris

which was tested at 20mbps due to the AVC Level 4 constraints. In brief:

You know, you can go up to 24mbps, and highest peak up to 30mbps. I think x264 at level 4.0 can beat everything else with 4.1

Originally Posted by kolak

Cinevision can at least match x264 or even produce better result for grainy sources

Agree, but only with nominal blu-ray bitrates, with lover bitrates x264 still produce better looking video.

[kolak]

Originally Posted by shon3i

Agree, but only with nominal blu-ray bitrates, with lover bitrates x264 still produce better looking video.

Yes- I've forgotten to add this.
I'm more BD bitrates guy, so I'm not realy interested in 5Mbit HD encodes (some time ago I was).

I've done some test recently and Cinevision was slightly better, but I know it quite well, so I can tweak it. x264 has more settings and I don't have experence with it. Difference was very small- but on 2x zoom Cinevision looked more clean. This was fairly noisy 30p source, so Cinevision shined with its grain optimization.

AQ stuff in Cinevison is very powerful, but also makes problems with some sources.


Andrew

[Lyris]

You know, you can go up to 24mbps, and highest peak up to 30mbps. I think x264 at level 4.0 can beat everything else with 4.1

I actually tried this, but x264 gave me warnings. The mistake is probably on my end - I've been experimenting with Mainconcept more lately. I will try a patched x264.

[nixo]

These warnings?

x264 [warning]: VBV bitrate (24000) > level limit (20000)
x264 [warning]: VBV buffer (30000) > level limit (25000)

Main profile is used during fast first pass. I think they can be safely ignored.

--
Nikolaj

[Revgen]

A) Here's my understanding of blu-ray compatibility. Please correct me if I'm wrong.

1) Levels can either be 4.0 or 4.1 for HD.
2) Level 4.1 requires at least 4 slices for Blu-Ray.
3) Level 4.0 doesn't require slices.
4) Limited to 3 b-frames or less.
5) Limited to 4 ref for 1080p. Limited to 9 ref for 720p.
6) Limited to 30000kb VBV Buffer size.
7) 4.0 is limited to a max-bitrate of 24000kbps for Blu-Ray.
8) Blu-Ray doesn't handle b-pyramid well.
9) "--nal-hrd" and "--aud" options must be enabled for compatibility.
10) Max Key Intervals must be set to 24. Minimum Key Intervals must be set to either 1 or 2.


B) Here's my list of questions about blu-ray compatibility.

1) Are there limits to subme? Megui's blu-ray profile has "--subme 2" toggled.
2) Are there limits to me? Megui's blu-ray profile has "--me dia" toggled.
3) Can trellis be used? It's disabled in MeGUI's blu-ray profile. If so, then how high can the setting be?
4) Are mixed-refs allowed? Megui's blu-ray profile has them disabled.
5) Is "--mvrange 511" necessary? It's included in the MeGUI blu-ray profile.
6) Megui's blu-ray profile has "--ipratio 1.1" "--pbratio 1.1". Can these be different? If so, is there a limit?
7) MeGUI's blu-ray profile has qcomp set to "--qcomp 0.5". Is this necessary? Or can it be x264's default qcomp setting?
8) Can I disable the inloop filter?

I don't expect anybody to answer all my questions, but if some of them can be answered, then I'd appreciate it.

[Chengbin]

Originally Posted by Revgen

B) Here's my list of questions about blu-ray compatibility.

1) Are there limits to subme? Megui's blu-ray profile has "--subme 2" toggled.
2) Are there limits to me? Megui's blu-ray profile has "--me dia" toggled.
3) Can trellis be used? It's disabled in MeGUI's blu-ray profile. If so, then how high can the setting be?
4) Are mixed-refs allowed? Megui's blu-ray profile has them disabled.
5) Is "--mvrange 511" necessary? It's included in the MeGUI blu-ray profile.
6) Megui's blu-ray profile has "--ipratio 1.1" "--pbratio 1.1". Can these be different? If so, is there a limit?
7) MeGUI's blu-ray profile has qcomp set to "--qcomp 0.5". Is this necessary? Or can it be x264's default qcomp setting?
8) Can I disable the inloop filter?

I don't expect anybody to answer all my questions, but if some of them can be answered, then I'd appreciate it.

Subme, merange, trellis has nothing to do with decoding. Use whatever you want. MeGUI has subme 2 and me dia toggles for first pass, where you can get away with crap settings.

I read that don't touch mvrange, leave it at 511.

Mixed-refs should be allowed, but I'm not 100% sure.

ipratio and pbratio has nothing to do with decoding. Those parameters just tell x264 the bitrate allocation for each type of frame. Use whatever you like.

I believe qcomp is lowered to 0.5 because Blu-ray has a maximum bitrate of 40mbps. At Blu-ray bitrates, qcomp of 0.5 can also save some bitrate because your bitrate is already so high. You can use any qcomp you like, just the higher the qcomp, the more chances of going over the maximum bitrate, and wasting bitrate on high motion scene when they have enough bitrates.

Of course you can disable inloop deblocker. Many Blu-rays disable that because they blur too much.

Hope this helps.