How does ProHD safeguard against dropouts?
JVC’s implementation of HDV actually has superior dropout compensation compared with DV. Vulnerability to tape dropouts is influenced by several factors including product design, media choice and environment. In its “mission critical” design, the GY-HD110U records in a relatively short 6-GOP (group of pictures) MPEG footprint (vs. 15-GOP of other HDV cameras) and features robust error correction, error concealment and relatively mild compression. In comparison with DV, critical I-frame picture information is interleaved over a larger physical portion of the tape with more physical separation from correction data reducing the potential for visible dropouts. Additionally, the camera and recorder incorporate extra “sweeper” heads preceding the record heads to help disperse foreign contamination during record and playback. A special mission-critical HD media (MDV-63PROHD) was created for ProHD.
