How do the professionals compress?

[dmz]

I have noticed that I burn at around cbr 6000 which gives me a pretty good quality but only about one and a half hours of video on a standard dvd. However when I play the bought movie videos, they seem to have 2 to 2 1/2 hours of even better quality than mine crammed into the same size dvd. Does anyone know how they are doing it?

[Ron P.]

What we do is burn DVDs, which uses a laser to etch the data into the disk. Professionals like Hollywood use a method where the disks are pressed and not burned. However that's not where they get the super good quality and able to place so much onto a SL disk.

They also use special encoders (costing much more then most people pay for cars or houses), that do up to 20 pass encoding. This is where they are able to really squeeze the data down so that they can get more onto a disk while not compromising quality.

[daniel]

Right Ron,
but you could also make a difference with the software encoding using massively parallel processing (well over your 20, you're not getting younger you know) doing all the passes together, and costing your house, Hollywood style, those are used for DVD mastering at very few authoring facilities, (the "Majors" studio don't have the money to pay for this equipment and they just subcontract),

and on the other side the hardware encoders used by the dozens (a 100 is not uncommon in a large studio) linked with ASI multiplexers and other signal processing equipment to encode MPEG-2 or MPEG-4 for Broadcast quality, those are the (large) car-priced models, they achieve lower quality, relatively speaking, but they do it real-time (as in on-air).

And so it happens that, even after 11 versions, Video Studio still doesn't achieve the same results.

[DVDDoug]

...but only about one and a half hours of video on a standard dvd. However when I play the bought movie videos, they seem to have 2 to 2 1/2 hours of even better quality than mine crammed into the same size dvd.

Are you sure they are the "same size"? Most of the commercial DVDs that I own are dual-layer.

Also, the studios are also starting-out with high-quality film, shot with high-quality cameras, by experts, with expert lighting, etc.

And, the experts also know how to get the most from their high-end MPEG encoders. They know how to "tweak" the encoder for scenes with lots of action and for scenes with lots of detail. Some of the users here know how to tweak the Ulead encoder (not me), but you can't really tweak it scene-by-scene. ...Most of us don't really understand the details of how MPEG compression works.

[daniel]

Are you sure they are the "same size"? Most of the commercial DVDs that I own are dual-layer.

Also, the studios are also starting-out with high-quality film, shot with high-quality cameras, by experts, with expert lighting, etc.

:?

Yes Doug but if you check the main feature film, without bonus etc, most often than not it's still no more than 5-6GB for about 2 hours movie.
The rest of the space is trailers, interviews, teasers and others.
And don't overlook the extra size taken by the various languages amongst which at least one in Dolby 5.1/DTS while we have one stereo track only. So DMZ's remark is still valid, relatively.

And of course your remarks about the importance of the source quality (definitely not already compressed SD DV-AVI) and the quantization params tweaking (taken care of by the multi-pass encoding) can't be overstressed.

Our only chance for the rest of us to get close is HD originals and performant MPEG-4 encoding for size. Prices will definitely go the usual way, divided in two every time the performance doubles. The only open question is timing.