User`s guide

38 007-4403-003
3: System Configuration
Configuring Video Compression
The PCI-VIDAUD-MSB-B multiformat codec (MFCODEC) devices support several file
formats for video compression: DIF, SGI MPEG-2, SMPTE 360M (playout only), and
MXF. The DIF video format supports DVCPRO 25, DVCPRO 50, DVCAM, and DV
(16-bit/48 Khz audio only) fixed-sized compression. To enable MPEG-2 video
compression, add the following line to the appropriate MFCODEC_n file:
vtr.media.video.input.compression.type mpeg2
Alternatively, you can use the SET command from mvcp to specify the format directly in
the unit context. Similarly, to enable DVCPRO 50 video compression, add the following
line to the appropriate MFCODEC_n file:
vtr.media.video.input.compression.type dvcpro50
IMX ingest requires an IMX-enabled PCI-VIDAUD-MSB-B card. The standard VST
controls (see the vst-controls(5) man page) configure these cards for processing
DVCPRO 25, DVCPRO 50, DVCAM, DV (16-bit/48 Khz audio only), or SGI MPEG-2
video signals for playout and ingest.
To create an IMX-compatible clip, the following controls must be set within the unit
context with the MVCP SET command or using entries in a device configuration file:
vtr.media.mpeg.bit_rate 50000000
vtr.media.video.input.constant_bit_rate true
vtr.media.input.compression.type mpeg2
vtr.media.video.input.compression.gop_structure I
vtr.media.video.input.compression.gop_size 1
For strict compliance with SMPTE 356M-2001, the 50 Mbps value must be used for
vtr.media.mpeg.bit_rate. However, an IMX-compatible deck can play clips
recorded at other constant bit rates.
MPEG-2 video coding can assume many compression formats, depending on the group
of pictures (GOP) structure and GOP size multiplier. The PCI-VIDAUD-MSB-B
MFCODEC supports four unique GOP structures: I (the default), IP, IPB, and IPBB—the
standard MPEG names. For a detailed discussion of MPEG video coding, consult the
website http://www.mpeg.org.