Pyro Industries API-1394PCI Manual de usuario descargar pdf (Pagina 27)

CHAPTER 1: INTRODUCTION TO AVID AND EDITING ■

For the uninitiated, a video frame consists of two fields. The picture first scans every

other line of resolution and then scans the ones missing from the first scan. These two

scans, which make up a composite image, are called fields. So when you used an Avid,

you showed only half the resolution of a picture. Additionally, the images created were

compressed. So much so that you could see “blockiness” or distortion of the picture

when it was played back on an ordinary TV.

Bummer. It seemed at that time that the technology would never catch up or

develop. But Avid told us that it was going to catch up and that we would eventually

be able to edit without going through any online processing or re-creating of the pic-

tures at high resolution. I didn’t believe them at the time, but they proved me wrong.

NuBus Avids

NuBus systems were so named because the Apple computer that was used at the time,

the Quadra 900 and Quadra 950, didn’t have enough processing power to run the Avid

software. As a result, Avid used additional coprocessors, which were connected to

Apple’s NuBus card architecture.

The basic Media Composer at that time (see Figure 1.3) used several coproces-

sors, including the following:

• Audiomedia or Pro Tools DigiDesign audio coprocessor

• Atto SCSI accelerator (this was used to play back the media at higher speeds so

that you could actually read 30 fields per second)

• Truevision NuVista card with an Avid-made daughterboard for video

• JPEG or Advanced JPEG card for reading the media files correctly (the

Advanced JPEG card was huge and connected to the NuVista)

All these cards were placed inside the computer. NuBus technology (as opposed

to PCI technology, which both Apple and PC makers use) consisted of rows of little

pins inside a plastic receptacle on the coprocessor, which were then mounted to a plas-

tic socket inside the computer.

Figure 1.3 That’s a NuBus Media

Composer under the desk.

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Pyro Industries API-1394PCI Manual de usuario Pagina 27