maybe playasia

3-D Bit Rates

These next two questions are related, so I'll address them together:

Q: There's a technical aspect of the 3-D Blu-ray standard that no one seems to talk about despite potentially being very important: bit rate. While I'm guessing (it hasn't been made very clear) that multi-view video encodes treat one of the two views (left or right eye) as a delta of the other (similar to how MP3s and MP4s use joint stereo), this undoubtedly lowers the amount of bandwidth available for each view. That being said, wouldn't 3-D releases have to be more compressed and thus be of inferior video quality? BRD media (3-D or not) is limited to 36 Mb/s, and let's not forget that you might be giving up up to 5 of those 36 MB to a lossless audio track. Now with 3-D, two video streams have to be accommodated in the same amount of space. While I understand you can get away with higher levels of compression and lower levels of detail when you're using 3-D, wouldn't it be readily apparent if you're watching a 3-D movie in 2-D since you're looking at a video-stream encoded at a lower bit rate than it would be if it were natively 2-D? Putting it as simply as possible: Logically speaking, since 3-D Blu-ray discs have to convey more video information with the same limitations imposed on 2-D media, isn't the video quality inferior?

Q: Is there any difference in picture quality between the same movie released in 3-D Blu-ray and normal (2-D) Blu-ray? I'm thinking of 'Avatar', which was released a year ago in 2-D. That was said to be the most perfect transfer of a movie on Blu-ray because it had maxed out all the free space on the disc. The creators had specifically kept the bit rates as high as possible and included no extras to ensure the best possible transfer. Now with a new version on the way which will be in 3-D, how can the same level of quality be kept when you have to put twice as many frames on the same disc?

A: While I'm not an engineer, I've heard it claimed that 3-D Blu-ray video requires approximately 1.5x the amount of disc space as a standard 2-D encoding. So, as you both say, doesn't that beg the question whether this automatically means that 3-D video is inferior in quality to 2-D?

No, it doesn't.

This goes back to a point I have discussed many times in previous columns. We in the home theater community spend too much time obsessing over bit rate statistics, which are more often than not misleading. It's easy to make the assumption that there's a direct linear relationship between bit rate and quality, as if you could judge how good a Blu-ray transfer looks just by watching how high the bit rate meter peaks. The truth of the matter is far more complicated. The bit rate required to encode any given frame is highly dependent on the complexity of the content in that frame. In many movie scenes, throwing more bits at the picture will yield only diminishing returns, and may not offer much of any tangible benefit over a lower bit rate encoding. The skill of the compressionist and the quality of the encoding are always more important than the arbitrary bit rate numbers hit.

Did 'Avatar' max out all of the available space on its disc? It came close. Did it look amazing? Yes, it did. Does that automatically mean that a lower bit rate encoding would have looked less amazing? Not necessarily. The 'Avatar' Blu-ray disc was encoded using the same principle as the old "Superbit" DVD line from Sony. Remember those? When Sony had a movie that it wanted to issue with no bonus features, the studio would crank up the bit rate to the maximum, call it a "Superbit" release, and charge extra for it. This was, more than anything else, a marketing ploy. Most Superbit discs were no better in quality than regular DVDs sold by any other studio.

The same situation applies to 'Avatar'. 20th Century Fox had no bonus features to offer with the first Blu-ray, so it bumped up the bit rate in order to advertise the disc as being "maximum quality." Now, the studio is issuing a new "Extended Collector's Edition" of 'Avatar' that includes a longer version of the movie and a bunch of supplements. And yet, somehow, I don't see anyone claiming that it's inferior to the previous disc. In fact, I was at a studio presentation last week in which James Cameron himself explicitly said – and I quote – "We didn't have to sacrifice the bit rate or quality." He said in no uncertain terms that the Collector's Edition looks just as good as the earlier disc.

But but but… How can that be? It has to have a lower bit rate to fit more material onto the same sized disc, doesn't it? Indeed, yes, it will have a lower bit rate. Is James Cameron lying? No. All this really means is that the maxed-out bit rates on the first 'Avatar' Blu-ray were mostly done for marketing purposes, not due to technical necessity. When the Collector's Edition hits, I will defy anyone to tell the difference in picture quality between it and the original release. The same goes for 3-D.

In no way am I trying to excuse certain studios from authoring discs with sloppy encodes filled with visible compression artifacts (which unfortunately does still happen). However, nor would I demand that all Blu-ray encodes hit arbitrary bit rate levels just because I want to see the meter on my player spike. We all need to spend less time watching bit rate meters (which aren't even accurate half the time, by the way), and more time judging quality by what we can actually see.

Nothing wrong with collectors of course. Just my type of collecting requires standard sized casings Wagons, treasure chest, briefcases won't fit on my tiny shelves

Wow! How did Sow manage to get the Casablanca set?! Awesome item to possess!

And guys, anyone bringing in Inception US?

3D sucks . I'd rather watch movie without having that useless glass on.

My main point is not 3-D but bit rate... 

3D sucks . I'd rather watch movie without having that useless glass on.

I won't go as far as saying 3D sucks  , but to me, the effect "divert" my attention towards the movie itself. Maybe on 2nd viewing onwards, wearing 3D glass will be an added bonus.

I think the following Q&A is quite interesting that I want to share with some forumers here 

Off record , regarding your movie review blog..are those review from your own words? 

Dude, yes it is. Plagiarism is E.V.I.L.

So, to sum up what the writer said.... does a 25Gb Jack Sparrow blu-ray disc be as good / on par with its 50Gb oris of the same title?? 

It depend on their compression skills      Use your eye and ear to test.  Those are best "devices" than any other equiupment.    After all, you use you eye and ear to watch movie and listen to music right? 

...and the third sense; your conscience... 

What do u mean free delivery? Which vendor gives free delivery?

Owh, I'm getting from Garage Sales.  Most of the sellers only give free delivery with two or more purchase.