Background

Compression and Quality

DVCPRO HD - Developed for High End HD Production

A key advantage of the AG-HPX500 is that it uses DVCPRO HD (DVCPRO 50/DVCPRO/DV). Since this high-definition format was introduced in 2000, its image and sound quality, reliability, and operating ease have earned the acclaim of broadcasters and video professionals all around the world. The original (standard-definition) DVCPRO format, introduced in 1996, has also seen wide use in broadcasting and other professional applications. Moreover, because a wide range of peripheral equipment has been developed for use with DVCPRO HD VTRs, DVCPRO HD gives you more versatility in editing and other post-production processes.

DVCPRO's Intraframe Compression System

All DVCPRO equipement uses intraframe compression with up to 100 Mbps. Data is produced and compressed independently for each frame, even in the case of DVCPRO HD and the huge amount of data it captures. This helps maintain superior pictures, sound and reliability not only in nonlinear editing, but also in tape editing using VTRs. You get greater editing flexibility and higher-quality results. Compared to DVCPRO, an MPEG2-based system uses interframe compression. A number of frames are formed into a group (called a GOP, for group of pictures) for processing. In each GOP, only frame I (for Initial) contains the entire set of image data. The subsequent frames P (Prediction) or B (Bi-directional) include the data that is different from the data in frame I.

DVCPRO HD's 4:2:2 Sampling Rate Is Most Beneficial for Professional Video Production

DVCPRO HD and DVCPRO 50 convert video signals to digital component signals at a 4:2:2 sampling (digitizing) ratio before recording. The resulting 4:2:2 digital component signal complies with the SMPTE259 Standard SDI signal specified in ITU-R601
DVCPRO HD format samples the brightness signal (Y) at 74.25 MHz and the chroma signal (Pb/Pr) at 37.125 MHz, and combines each set of four Y samples with two Pb and two Pr samples. With the large amount of information it provides for the color difference signal, this system helps maintain outstanding color resolution.

Differences in Audio Recording

DVCPRO HD format supports professional-level audio specifications with up to eight channels of uncompressed 48-kHz, 16-bit digital sound. AG-HPX500 itself can record up to four channels of audio. In HDV, audio recorded in MP2 format is compressed to 384 kilobits per second.