GRASS VALLEY Profile XP PVS1000, Service Manual

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MPEG-2 Encoder and Decoder boards (PVS1000 Series)
23 July 2004 Profile XP Service Manual 163
MPEG-2 Encoder and Decoder boards (PVS1000 Series)
The MPEG-2 Encoder board receives an uncompressed video stream of CCIR 601
video data from the video/audio crosspoint fabric and compresses (encodes) it into
MPEG-2 format. The MPEG-2 video is then sent over the PCI bus to the media
storage subsystem.
The MPEG-2 Encoder board features the following functions:
• Two (2) channels of MPEG-2 encoding at a maximum bit rate of 50 Mb/s, and at
a minimum bit rate of 4 Mb/s
• Simultaneous extraction of VBI data from both video channels on lines 10 through
22 NTSC and 6 through 23 PAL
• Extraction of 720 bytes of luminance and 720 bytes of chrominance data
The MPEG-2 Decoder reads compressed MPEG-2 video data from a local memory
buffer, decompresses (decodes) the video data, and outputs a CCIR 601 video data
stream to the video routing fabric.
The MPEG-2 Encoder and Decoder boards are controlled by the RTP via the PCI Bus.
HD MPEG-2 Encoder and Decoder Boards (PVS 2000, 3000, and
3500 Series)
The HD MPEG-2 Encoder provides one channel of video processing; the HD
MPEG-2 Decoder provides two channels. The maximum decoding rate is 80 Mb/s,
while the minimum usable rate is around 30 Mb/s. Video routing for HD in record and
play modes is the same as for SD.
Video Processor board (PVS1100, 3000, and 3500 Series)
The Video Processor board provides either two or four channels of video processing.
Up to eight channels can be installed in a Profile XP system.
In their default configuration, the codecs on the Video Processor board are set for
DVCPRO 25 operation. A codec can be reconfigured to be either an MPEG codec, an
MPEG encoder, or an MPEG decoder, with bit rates selectable from 4-25 Mb/s. With
the 50 Mb/s software option installed, each codec can be configured for DVCPRO 50
operation, MPEG D10 operation, or MPEG operation up to 50 Mb/s. When a codec
is reconfigured, the media platform must be rebooted to put the change into effect.
For record mode, video is routed from the Video I/O boards, over the video transport
fabric to the Video Processor board. Compressed data is moved over the PCI bus to
the Media Storage Subsystem. For play mode, compressed data is routed from the
Media Storage Subsystem, over PCI bus, to the Video Processor board where the data
is processed. Full bandwidth video is routed from the Video Processor board over the
video transport fabric to the Video I/O boards.