DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

D-7 (DVCPRO),
DVCAM
runs twice the speed of 480i Hi8, or 1.5 times the
speed of 576i Hi8, leading to a corresponding reduction
in the record time indicated on a Hi8 cassette.
Studio adaptation of DV technology
DV technology has been adapted to professional use.
The DVCPRO format (developed by Panasonic, and
standardized by SMPTE as D-7) and the DVCAM format
(developed by Sony) both use DV25 coding identical to
consumer DVC; their tape cassettes are virtually identical
to those of DVC. However, the formats are
different: Both use wider track pitch than DVC, to
obtain more robust operation. DVCAM has 1.5 times
the track pitch (and track width) of DV, and 1.5 times
higher tape speed, resulting in 2 ⁄3 the recording time for
a given tape length. DVCPRO has 1.8 times the track
pitch and speed, resulting in 55% of the recording time
for a given tape length.
DV coding has been adapted to a data rate of 50 Mb/s
(DV50), to achieve higher quality for studio SDTV.
D-9 (Digital-S) JVC adapted the DV50 scheme to 1 ⁄2-inch tape in
a VHS-size cassette. This was introduced as Digital-S,
then subsequently standardized by SMPTE as D-9.
DVCPRO50 Equipment using DV50 coding for 480i and 576i was
introduced by Panasonic as DVCPRO50. The format was
subsequently incorporated into a new revision of
SMPTE’s D-7 series of standards, which formerly
applied just to DV25.
DVCPRO P
(DVCPRO50 P)
Equipment using DV50 coding for 480p has been
introduced by Panasonic, and denoted DVCPRO P or
DVCPRO50 P. A medium-sized cassette augments the
small and large cassettes used for DVCPRO.
D-10 (MPEG IMX) Unrelated to the DV developments, Sony developed
a videotape format, introduced as MPEG IMX, that
compresses 480i29.97 or 576i25 SDTV to about
50 Mb/s, for recording onto 1 ⁄2-inch tape in a Betacamstyle
cassette. The format was standardized by SMPTE
as D-10. I-frame only MPEG-2 compression is used.
CHAPTER 35 VIDEOTAPE RECORDING 425