Doremi MCSHD - Manual (Page 10)

1 Introduction
Thank you for your V1 purchase. The V1 is a random access video recorder that uses magnetic
drives (hard drives) as a recording medium.
To record video on a hard drive it should be digitized which means that the analog video information
must be converted to a digital data stream.
The V1 line of products includes uncompressed video recorders (8 and 10 bit encoding) and
compressed video recorders, the trade off is between storage requirement and video quality.
Hopefully this introduction explains to the reader the basic technical principles of digital video disk
recording.
1.1 V1 Uncompressed HD
The V1-UHD and V1-UHD/LE (for HDTV video) series records the video directly on the hard drive
without the use of compression. The value priced V1-UHD/LE supports 8bit HD video recording
only.
1.2 V1 Compressed HD: JPEG2000
Doremi’s V1-HD product line uses JPEG2000 video compression.
1.3 The CBS Algorithm
The V1 uses a constant block size (CBS) algorithm. With traditional compression algorithms,
depending on video complexity, the size of each compression field can vary thus requiring
maintaining a list to indicate the start of each field on the drive. With CBS all fields have the same
maximum size. Consequently, CBS does not require maintaining a list indicating the start of each
field because they are all the same size. This results in a more reliable video recorder with faster
video access and frame accurate recording.
1.4 Audio and Time Code
In addition to the video, and regardless of the compression ratio used, the V1 records 2, 4, 6 or 8
tracks of uncompressed audio (sampled at 48Khz). It also records the LTC and digital-VITC
timecodes.
V_1.OM.000160.DRM Page 10 of 85 Version 5.2
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