Compression Discussion Thread

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This is a thread for the discussion of compression issues (video and audio) for Blu-ray, HD DVD and beyond.

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Originally Posted by b2bonez

The one thing I would love to know is if the AVC encoders are using CABAC entropy compression. That sounds like a good question for paidgeek...

(For those who are unfamiliar with CABAC, it is something of a super "ZIP" lossless compression that is a optional encoder setting in the AVC profile used in both formats. What it does is wring out those last few bits from the encode and does it lossless. So in effect you can encode using a "best quality" setting and let CABAC do all the bit twiddling like VC-1 does under operator control. Downside is it is very taxing on the encoder to do and increases the encode time.)

b2b

Do you have any metrics on the encode cost?

What is the decode cost? And is the feature required in BD or HD DVD decoders?

Gary

[Rivera213]

Well, the less compression of the audio- the better i'm assuming?

The 100GB, 4-Layer disc will store more sound data (7.1) so you wont need to compress it as much?

I believe that's the case.

With video, 1920x1080 is good enough on a LCD HD-TV of 52" or so, it's bad ass picture.

With the Dolby 7-Speaker set-up (and the effects box) for 7.1 audio, for me recording my playing onto a 100GB disc (and potentially a 200GB) disc, it'll be a musical orgasm.

I personally don't know HOW to compress audio or video.

The camera i have in mind later down the line shoots at full 1920x1080 HD & i guess using MPEG-4 compression (cos HD-SDI is for studios only i think), so the video compression wont be too hard. The audio however i don't have a ****ing clue what to do.

If it's just a box you plug the camera in to then connect that box to the Blu-Ray recorder then that's fine.

I don't know how to enable 7.1 sound though? I'm guessing computer or editing software?

[kuklitis]

Quote:
Originally Posted by paidgeek
Amir, your guarantee does not make sense based on titles that use both codecs in the market. I respect that you are passionate about VC-1, but continuing to be so adamant regardless of observable results leads me to think this is a religious crusade rather than an objective pursuit for the best possible picture quality.


For a guy who fought a crusade just to see advanced codecs in Blu-ray, I say the results are there to back up such efforts . But I am happy to explain the logic more.

The key thing that you fail to note is that you are encoding MPEG-2 titles at much higher data rates than VC-1. So if MPEG-2 is a great codec, you should be beating VC-1 in quality, yet at most, you match it, but often come up short. The best example we have are Warner titles which you encoded in MPEGt-2. Here is the review of MPEG-2 Training Day on BD which is a top tier HD DVD title: http://bluray.highdefdigest.com/trainingday.html

"'Training Day' on Blu-ray has a lot to live up to. Had this title been released on the format before it hit HD DVD, it likely would not have come under nearly as much scrutiny. Videophiles have been waiting with bated breath to see not only if 'Training Day' looks great on Blu-ray, but if it tops or at least equals its rival. Surprisingly, the differences between the two versions is substantial in more ways than one -- and unfortunately for the Blu-ray camp, though it is quite a close race, it ultimately doesn't go Blu-ray's way.

To assess picture quality, I did comparisons of three complete scenes on both discs, one after the other, simply by switching between my set's two inputs. I also compared a dozen individual still images, by pausing each deck on identical still frames and switching back and forth. The picture quality differences between the two transfers is often quite apparent. For example, during the very first shot of the film -- a zoom in on a red-hot, rising sun – there was some posterization was visible on the Blu-ray, with the banding of colors obvious as the picture faded in. Looking closely at the HD DVD I could also spot some posterization, but it was not nearly as severe. These type of compression artifacts continued throughout both transfers, and I noticed about three or four shots on the Blu-ray with more polarization on backgrounds or during fades/dissolves, which were either not there on the HD DVD, or greatly lessened. So score one for HD DVD's VC-1 compression codec over the MPEG-2 scheme used for Blu-ray -- at least until that format's larger-capacity BD-50 dual layer discs become commercially viable."

And Rumor Has It: http://bluray.highdefdigest.com/rumorhasit.html

"Compression artifacts, too, are also more distracting. I detected a few patches of what looked like noise or blockiness on such objects as flat, color walls and fabric patterns on the Blu-ray – the HD DVD just looked more consistently cleaner and clearer. Again, none of these drawbacks are monumental, but the discerning eyes of this early adopter left me a tad disappointed with the Blu-ray.”

Note that Rumor Has It is a combo disc with only 15 gigabytes of capacity (newer combos do 30), compared to BD-25. So despite a capacity disadvantage, we came out ahead.

Admittedly, Peter Bracke considers MI3 to look the same on both formats. But the other reviews clearly show that despite having considerable advantage in peak bit rate using MPEG-2, you still did not manage to match our VC-1 quality.

Of course, we also know that Warner switched away from your MPEG-2 encode as fast they could. If life was great in MPEG-2 land, surely they would have continued using it.

Yes, there are some new BD titles that do look very nice. But there is no VC-1 version to compare to. And given your recent statement that you are releasing what looks good in BD, one is left wondering if test encodes are done and if something doesn’t look good, they are put back on the shelf.

So going back to the original question of people wanting even more quality than VC-1 provides in HD DVD, my question remains why one dose not exhaust the quality that could be there by just switching codecs from Sony side. After all, you are the only studio 100% on MPEG-2 today. No other studio has even come close to have the kind of marriage that you have with MPEG-2. All other major studios have released titles in advanced codecs, including others in your camp. Are you really the smartest one of the bunch by staying with MPEG-2 for so long?

And how about only using AVC, when your own encoder is ready. Doesn’t this seem like a coincident that the only time advanced codecs look good is when your own encoder is ready? And your preference to use that when it runs so much slower than our VC-1 encoder? Me thinks your internal directives to use Sony technology overrides the strive to create the absolute best quality. This is clear from studios who don’t build encoders and how free they feel to use advanced codecs.

As I have mentioned before, we gain very little from you using VC-1. People are indeed surprised that help the blu-ray side at all this way. If Warner had not rolled out their titles last year with VC-1 and erase the poor showing of BD format with MPEG-2 prior to that, there is no telling where BD format would be today.

So why do we do it? Believe it or not, it goes back to a promise I made to a Sony executive some 3 years ago. When challenged that we would disadvantage Blu-ray should they allow VC-1 in the format, if we choose to go the HD DVD route, I said they would have our word that would treat them as well as HD DVD studios. So this is why we wrote the BD conversion tool for VC-1. And why make our services fully available to you. To the extent you turn our offer down, my conscious is clear and we can move on to concentrate our efforts to help all the other HD DVD studios get even better quality out of their products….

[WriteSimply]

Originally Posted by kuklitis

Quote:
Originally Posted by paidgeek

Please edit your posts to include links of the original posters. For one, I don't believe that either Amir nor paidgeek wrote that because the post doesn't sound like it is from either of them.

To quote someone, use [ quote ] and [ /quote ] - obviously there is no space after the [ ] .


fuad

[blitz6speed]

Looks like Amir confirmed that sony just recently rejected MS's VC-1 proposal. Guess its time for HD-DVD to do what it does best, make 720p porn available to the masses!

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Originally Posted by blitz6speed

Looks like Amir confirmed that sony just recently rejected MS's VC-1 proposal. Guess its time for HD-DVD to do what it does best, make 720p porn available to the masses!

Is that recent? I think maybe it is the now old and ongoing offer of assisting in the creation of a VC-1 encoder tool for Sony's Blu-print suite.

Notice how creating a porting tool from HD DVD to BD is supposed to make us cheer?

Gary

[dialog_gvf]

I guess I should respond to Amir's comments to paidgeek here too:


Step 1: Bring up an issue relevant only to HD DVD due to its lower bandwidth:

The key thing that you fail to note is that you are encoding MPEG-2 titles at much higher data rates than VC-1.

The key thing he fails to note is that HD DVD is incapable of supporting the bandwidth. It is a format DESIGNED for VC-1. Deliberately designed to exclude use of MPEG-2 except on very short encodings. And then they strut around as if VC-1 is the only solution.

Step 2: Dig into the past for some reviews (rather rdjam of him):

Training Day:
Reviewed by Peter M. Bracke
Monday, July 31, 2006

Rumor Has It... (Blu-ray)
Reviewed by Peter M. Bracke
Tuesday, August 01, 2006

So, Amir is living in Aug 1 2006. Rather modern of the chap. Most of the HD DVD fanboys live in June 2006 when The Fifth Element was released.

Care to join us in the present boys?


Step 3: Bring up mythical facts:

Admittedly, Peter Bracke considers MI3 to look the same on both formats. But the other reviews clearly show that despite having considerable advantage in peak bit rate using MPEG-2, you still did not manage to match our VC-1 quality.

Link to just one of these other reviews? He didn't seem to have trouble digging up the other two.

Gary

[blitz6speed]

Originally Posted by dialog_gvf

Is that recent? I think maybe it is the now old and ongoing offer of assisting in the creation of a VC-1 encoder tool for Sony's Blu-print suite.

Notice how creating a porting tool from HD DVD to BD is supposed to make us cheer?

Gary

Paidgeek has been saying hes under NDA about VC-1 as they are evaluating a recent version from MS. Then last nights post by Amir pretty much spells it out that Sony didnt like what it saw and now amir is even more pissed. At least, thats how ive read it so far =)

[dialog_gvf]

Ah, I see. Interesting.

How professional of Amir to leak discussions like that.