Which Codec for Bluray?

[mr_yogi]

As the title says, has it been decided which Codecs (MPEG2/ MPEG4/ other?) Bluray disks/ players will use?

Thanks :)

[stefmcd]

As the title says, has it been decided which Codecs (MPEG2/ MPEG4/ other?) Bluray disks/ players will use?

Thanks :)


Good question. Surely the codec would have to be decided far in advance of the launch i.e. ages ago. I would also have thought it would be a proprietary codec to reduce piracy/hacking etc. I could be wrong but I await an answer with interest.
:)

[Alistair_M]

going by the posts by insiders on avsforum,

for sony/mgm releases - launch titles in mpeg2. Later titles (who knows when+ later) will be in AVC/VCI. Sony has little interest in using VCI because of microsoft, so I think they will only use that if AVC doesn't work out as the advanced codec format of choice.

other studios - I think some mpeg2, some vci, some avc. I think Warners will use vci for their titles, as thats the codec they are using for the hd-dvd releases. It wouldn't make commercial sense to do the transfers again, and I expect they learnt a lot when they were doing the transfers for hd-dvd. Warner and microsoft have a good working relationship too, so that helps Warners pick VCI for their codec.

I've heard a lot of good things about VCI. The japanese release of resident evil2 on bluray used AVC and the quality was supposed to be pretty poor really. I think it will take time to get the best out of the new codecs.

[Angry the Clown]

The hardware has to support all three. That's mandatory.

For the discs themselves, it is up to the studios. Alistair pretty much has it right. As has been stated, Sony/MGM will be sticking with MPEG2 for the foreseeable future. Warner will use VC1, and it's generally assumed Lion's Gate is to use MPEG2 as well.

It is believed Fox are favouring MPEG4 for their titles. Paramount have been rather quiet on the subject, and it's been said Disney favours MPEG2 for the time being - although, again, they're another studio which has as yet to categorically state what codec they will be using.

[stefmcd]

Why is mpeg2 encoding still so popular?

Is this not an extremely inefficient codec by up-to-date standards?

How old is mpeg2? 8-9 years? Seems a bizarre choice for a new medium.

or is it considered so stable and means less costs involved without adopting new encoding as well as new format?
:)

[Angry the Clown]

Well, I think certain studios feel they know where they are with MPEG2 at the moment...and one (can you guess who?) might just happen to have well over 100 patents in it. ;)

[paulfoley]

I read an interview with Sony last week (sorry cant remember the site) - they said that they had tried all three codecs on their films & still found that MPEG2 produced the cleanest picture !

;)

[AML]

Mpeg 2 uses less compression that Mpeg 4 so I can see why sony would think it looks better.

The only reason HD DVD need Mpeg 4 is because of the lack of space on their disks compared to sony.

Its a bit like comparing a CD with an MP3 file. Even though MP3 is newer technology compared to the CD or even a Record, both CDs and records offer better sound quality than even the best MP3s.

[Jeff]

They use Mpeg2 because they need to fill the extra space with something, if they released discs that are only half full people will start to ask what the point of Blu-ray is.

[Angry the Clown]

I read an interview with Sony last week (sorry cant remember the site) - they said that they had tried all three codecs on their films & still found that MPEG2 produced the cleanest picture !

The slight problem with the tests they undertook was that they were running MPEG 2 at around 25-30mbps and comparing it to their original HD master, and 25-30mbps exceeds the data rates Sony have said they will actually be using for video on their finished titles. They’ve been quoted a number of times now that they will be using variable bitrate peaking at around 18 or 19mbps.

Sony have admitted the advanced codecs are as good as/better at lower peak bitrates, so in that respect they make their arguments for using MPEG2 as far as quality is concerned still somewhat patchy, whereas their reasons for siding with it due to patent issues and the fact they might find it more reliable given it’s age make a lot more sense. I’m not even sure they extended their tests beyond MPEG4 vs MPEG2 to include VC1, but as I say - I’m not certain. It’s been a while since I read the reports from the testing sessions.


The only reason HD DVD need Mpeg 4 is because of the lack of space on their disks compared to sony.

Well that’s a half truth. Blu Ray was initially developed as an MPEG2 based format, where as HD DVD was developed with the advanced codecs in mind under the knowledge the advance codecs would ultimately become the standard. One of the things to be grateful for in having two formats compete has been that HD DVDs spec ensured Studios demanded the same of Blu Ray, and subsequently new audio and video codecs were added at their request.

There’s no grounds to saying it is a space argument, not when Sony is using MPEG2 and uncompressed multi-channel PCM alongside standard Dolby and full bitrate DTS tracks to stuff single layer 25gb discs which they consider to be “more than enough” as far as storage for movies is concerned. It is here where Sony’s boasting becomes questionable because if they seek to add extras and interactive content on top of all that on their 25gb releases then I’d think there is some cause for concern. Of course, we know what Sony are like, using MPEG2 now and MPEG4 at a later date puts them in the ideal position to potentially re-issue the same movies again with a wealth of supplements given they’d have more space freed up. That is something I do not put past them.


They use Mpeg2 because they need to fill the extra space with something, if they released discs that are only half full people will start to ask what the point of Blu-ray is if they released discs that are only half full people will start to ask what the point of Blu-ray is.

That makes little sense, Jeff. They’re filling it sure, but needlessly wasting space in the way they’re going about it. They’re filling more with less essentially. Consider again that Sony’s titles are MPEG2 with uncompressed multi-channel PCM, Dolby and 1.5mbps DTS on a 25gb disc. There’s not actually going to be much room for anything else (though I don’t put it past them to squeeze some supplements on there as well potentially at the expense of the A/V quality).

Compare that to Warner’s titles coming to HD DVD. All 30gb releases, and they’re filling them up very nicely in using VC1. 1080/24p encode for the film, 480i for the extras. Dolby Digital Plus as standard, and one of the three launch titles (Phantom of the Opera) also has 5.1 True HD lossless track. Allegedly Warner is capping their HD DVD releases at 25gb so they can port the exact same content and masters to a 25gb Blu Ray disc in June/July, so ironically Warner’s Blu Ray releases may show the potential of the next gen formats far better then the Sony/MGM titles might.

[AML]

A lot of what you say is true, but at the end of the day the more you compress the more quality you loose.

I want to see a format that can have an entire movie without any sort of compression. I dont care how much space it takes up. Maybe holographic disks will be the way forward in terms of quality.

If you ask me, both Blu Ray and HD DVD are just a minor step up from DVD. Slightly higher resolution. Thats it.

The only positive upgrade is the lossless uncompressed soundtracks. And maybe the higher bit rates.
I still feel we will have compression artefacts and so on.

How much space would a lossless movie need?

[Angry the Clown]

A lot of what you say is true, but at the end of the day the more you compress the more quality you loose.

Well you need to look beyond the data rates because MPEG4 and VC1 are very different beasts to MPEG2. Done right, they can do a job as good as, if not better than MPEG2 in a far more efficient and space saving manner. They are new though, and require some talented people to get the best of in a mastering environment. This will change in time as decoders become more freely available in the industry.


I want to see a format that can have an entire movie without any sort of compression. I dont care how much space it takes up.

You won’t see that. I'm not sure you'll ever see that. Compression isn't necessarily a bad thing. It's up the talent of the people doing the compression where any concerns should lie. As DVD has shown us, some jobs are done well, some jobs aren't. Sadly this inconsistent trend will probably continue with the HD formats, but nobody should really fear the codec choice any studios make in terms of its compression ratio alone.

[wooski]

From my limited knowledge of professional video I can tell you full uncompressed is around 270Mb/sec. Most video professionals are happy to take a 50Mb/sec MPEG2 as "master" quality (ie even they can't tell the difference on a grade 1 monitor). So if HD-DVD and Blu Ray is encoding at between 15Mb/sec to 20Mb/sec you're still 2.5 to 3 times lower. However this is still approx 3 times better than DVD.

I'm led to believe that Digital effects in movies are worked at a resolution around 4000 pixels across - just over double the 1920 horizontal resolution of 1080. You need this for projecting in a cinema - but would you really see the benefit in the home environment? I suspect most people wouldn't. The leap from 480 to 1080 is significant - but much higher and people arent going to notice.

[Mr.D]

I'm led to believe that Digital effects in movies are worked at a resolution around 4000 pixels across - just over double the 1920 horizontal resolution of 1080. You need this for projecting in a cinema - but would you really see the benefit in the home environment? I suspect most people wouldn't. The leap from 480 to 1080 is significant - but much higher and people arent going to notice.


Most effects work is carried out at 2K (2048x1556 for a fullap 35mm film frame). Full res is 4K (4096x3112). 2k is regarded as indistinguishable from 4k on projection .

1080p is 8bit video. film scans are 10bit log encoded film colorspace ( cineon) more like 20bit linear and the scan represents full range density...that is negative density ...in effect its the same capability of the film in the camera when they shoot it. Comparing this to compressed hidef video is like comparing a ford capri to an F15. Different animals , different purposes, apples and oranges.

[Dolphin]

As the title says, has it been decided which Codecs (MPEG2/ MPEG4/ other?) Bluray disks/ players will use?

Thanks :)

I have seen at a few websites (anandtech and other good ones) that they will use the H.264 codec based on mpeg4 V10. You can watch clips of H.264 from the apple website.

Divx6 HD and Microsoft's WMV9 apparently did not make it.

[DanielTS]

How much space would a lossless movie need?
The Storage Numbers :
http://www.microsoft.com/windows/windowsmedia/howto/articles/UnderstandingHDFormats.aspx#storageneedsforhdcaptu re

[NicolasB]

A lot of what you say is true, but at the end of the day the more you compress the more quality you loose.Quite wrong, I'm afraid. MPEG4 is inherently more efficient than MPEG2: you can get the same picture quality with a lower bit-rate, or a better picture quality with the same bit-rate.

The reason why Sony Studios have decided to use MPEG2 is unclear. It may be because MPEG2 has been around long enough that technicians know precisely how to use it. Compressing video is not a simple process - in some cases it's more of an art than a science. People know how to compress MPEG2 streams without introducing any more artefacts than are absolutely necessary. MPEG4 is still a comparatively unknown quantity, and it will take a while for the technicians to get comfortable with it.

It's also theoretically possible (but unlikely) that the first generation of BluRay players may do a better job of decoding MPEG2 than they do with MPEG4, as a result of either a lack of processing power or a lack of experience in producing decoding algorithms. (Even decoding video is not as exact a science as you might think: look how many DVD players even now still have the chroma bug - that means they're decoding MPEG2 incorrectly. Decoding MPEG4 well may require a couple of iterations to get right.)

There are also a number of hi-def MPEG2 recordings already out there (for over-the-air broadcast in the US, etc.) so possibly some of these could be directly transferred to BluRay.

Personally I'm inclined to go for the conspiracy theory: Sony Studios are the guys who deliberately cripple the sound and picture quality of their DVD releases so that they can release an uncrippled version later, call it "superbit", and get customers to buy the same title twice. They may be planning to do the same thing with BluRay: release a poorer-quality MPEG2 version first, then follow it up with a better-quality MPEG4 version farther down the line as a superbit equivalent.

[Angry the Clown]

2k is regarded as indistinguishable from 4k on projection.

I think that’s fairly true if speaking on behalf of the average cinemagoer sat at the typical seating distance, but those with trained eyes should most certainly still be able to see a difference. With 2k things seem to hit a level of “good enough” amongst those in charge which is a term I loathe to hear uttered amongst anyone in the film industry, but I’m glad you specified ‘on projection’ though as like I say, to a degree I agree with you although I would say that if a majority of cinemagoers can’t tell the difference it shouldn’t necessarily mean it (4k projection) shouldn’t be implemented as a standard as I do believe there to be benefits.

In the digital intermediate process I’ve certainly found that the very smallest details and granular structure of the stock are retained at a greater level at 4k resulting in a capture that is far more faithful to the 35mm source. 2k, to me, generally seems to introduce a digital sheen over the image as result of it not being able to render the finest grain structure appropriately as well as its susceptibility to introducing various digital image artefacts visible both in the DI stage and when printed and projected back on 35mm (or projected digitally).

If we’re specifically talking visual effects – which I believe having read another thread is your area? – I certainly agree rendering CG work at a lower resolution is fine. As you probably know, Spider-Man 2 and I, Robot both had 4k Digital Intermediates but all the effects work was 2k and upscaled. Final results were terrific.

I love film and will always strive to respect the levels of detail a film stock can capture and hope that theatrically it can be displayed at its very best. In the case of the latter we of course know this to be difficult, not due to fault of film projection, but the inept 15 year olds who run many a projection booth and have had no training in how to handle a print properly. I’m pleased all the studios are looking to restore and archive their catalogues at 4k now the costs are becoming more feasible and it’s partly for these reasons I’d much prefer 4k projection in cinemas because cinema should not be a business of compromise, and even if – god forbid - shooting in HD becomes the standard far sooner than I’d like, the back catalogue of films shot on film will far outnumber those shot in hi def and again, digital projection should accurately be able to represent everything be it sourced from HD, 35mm, 65mm and so on – so in terms of the bigger picture I do think 4k is the way to go with D-Cinema.

Anything beyond 1080p in the home I don’t think consumers will ever benefit from (at least not in our lifetimes). Besides, there should always be a distinction in quality between home cinema and cinema itself in my opinion, and these days the former has a leap over the latter and this needs to change. I think the most AML might be able to expect in the future is 1080p again but with improved chroma sampling and the like. Studios can still churn out another 1080p format to replace HD DVD and Blu Ray one day (which they will) and still provide some benefits in that department.


Personally I'm inclined to go for the conspiracy theory: Sony Studios are the guys who deliberately cripple the sound and picture quality of their DVD releases so that they can release an uncrippled version later, call it "superbit", and get customers to buy the same title twice. They may be planning to do the same thing with BluRay: release a poorer-quality MPEG2 version first, then follow it up with a better-quality MPEG4 version farther down the line as a superbit equivalent.

I pretty much agree. Sony’s catalogue is poor. It’s relatively small and littered with a lot of bad movies (for goodness sake look at their Blu Ray launch titles!). They are of course aware of this and their desire to re-issue the same product over and over again is immense. Getting that 20% share in MGM and the right to distribute the MGM catalogue has helped them a little, but they’ll probably exploit MGM titles just as badly. Sony have even admitted most of the HD masters they’re using are ones they began creating years ago, the very same ones the majority of their DVD titles have stemmed from.

Other studios, Warner most notably, are really doing well in trying to do the best they can from the get go, which is why I say it’ll be ironic given their initial HD DVD only stance that Warner’s own Blu Ray titles this year are likely to well exceed those from Sony themselves on various levels.

[Mr.D]

I'd have to say I'm firmly in the camp that believes 2k (assuming you have decent scanning and recording) is good enough.

[shaithis]

I was under the impression that MPEG4 was a lossLESS compression......so i wonder just how MPEG2 looks cleaner....unless of course they are using some dodgy decoder.........or telling porkies ;)

[NicolasB]

I was under the impression that MPEG4 was a lossLESS compression......so i wonder just how MPEG2 looks cleaner....unless of course they are using some dodgy decoder.........or telling porkies ;)No, MPEG4 is lossy too, it's just more compact: you get a better picture for the same bitrate, or a lower bitrate for the same picture quality. Any such algorithm is a trade-off between bit-rate, quality, and the amount of processing power needed in the encoding and decoding process. MPEG4 assumes that you have more processing power at your disposal than would have been the case for a few years after MPEG2 was produced. It requires a lot more processing power to decode MPEG4 than MPEG2, and major processing power to encode MPEG4.

[Angry the Clown]

I'd have to say I'm firmly in the camp that believes 2k (assuming you have decent scanning and recording) is good enough.


*waves fist* :grin: ..but yes, in fairness opinions seem split amongst many in the industry. I'm still glad, as I say, that at the very least studios are looking to a 4k standard for archival and restoration. I'm not sure Sony's 4k projector can make a significant dent in the investment and rollout being put into installing 2k DLP into many cinemas across the globe now which to me - obviously - is a shame.