The goal is to bring all of the emotional excitement of movie images directly into the home. And MPEG-4 AVC High Profile image compression technology was developed to do exactly that.
We asked a Panasonic image compression professional, Toshiya Takahashi, to fill us in on some of the details.
AV Core Technology Development Center
Well, it takes a very advanced method to record high-quality images onto a disc. The Blu-ray Disc uses two of them. One is MPEG-2, which is used in conventional digital broadcasting, and the other is a new one called MPEG-4 AVC High Profile, which is a high-efficiency encoding method (a system for converting image data into digital data). The new method, which was developed for the Blu-ray Disc standards, aims to improve on both image quality and compression efficiency compared with existing image compression methods.
Yes, that's right. But let me explain the background a bit. Ordinarily, when a company wants to launch an entirely new image compression method, it has to submit a proposal to the MPEG standards organization, which examines it to determine whether it can be used or not. In this case, though, Panasonic received the cooperation of several Hollywood film companies and strongly promoted the advantages of the MPEG-4 AVC High Profile method. As a result, the strength of the method was recognized and it was formally approved. This made it possible to fit almost all of the image-quality data of an ordinary film onto a single disc.
In addition to Blu-ray and other optical discs, though, many people agree that the MPEG-4 AVC High Profile method may also become the mainstream data compression method for applications like cellular phones and TV broadcasts.
Yes, we developed an MPEG-4 AVC High Profile encoder for BD-ROM production work. An encoder is basically the system that compresses the images. The encoder that Panasonic developed compresses MPEG-4 AVC High Profile images with extremely high quality and speed. It's on the cutting-edge of image editing.
The following diagram shows the editing workflow for burning a movie onto a Blu-ray Disc. The stage that uses the MPEG-4 AVC High Profile method is circled in red. This is where the true quality of the disc is determined.
In the industry, the image compression process is called encoding. First, the original images received from a film company are uploaded to an encoder system like the one in the photograph below. This system processes high-resolution images at high speed.
The next photograph shows an encoding room. The encoding is done by using pairs of monitors sitting side-by-side to compare the original, non-compressed images with the finished, compressed images. In addition to checking for places where desired elements of the original might have been lost in the process, the compressionists go through the footage one cut at a time to optimize the Blu-ray Disc image quality.
The theme of the movie, and the intentions of the director and art director, are naturally different for each film. The compressionist has to have a natural understanding of these aspects, and the ability to render colors and textures with extreme precision. He or she also has to have the technical knowledge to spot problems in the compressed images, and make quantitative improvements.
Also, compression is done cut by cut, but one of the most important jobs of the compressionist is to know just how much data can be applied to each scene in order to fit the entire film within the limited data capacity of the disc.
Panasonic has people who specialize in encoding on its staff both in Hollywood and Roppongi, Tokyo, and they meet the needs of numerous film companies. We are also already training the next generation of compressionists and other staff.
Yes, I'd just like to say that we'll be maintaining the close relationship that we've built up with Hollywood's film companies, and providing movies with the ultrahigh image quality of the MPEG-4 AVC High Profile method. Please look forward to watching these remarkable Blu-ray Disc images on your own large-screen TV.