TANDBERG Voyager E5784, Справочное руководство

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Introduction to the Basic Encoder
Reference Guide: Voyager E5784 and E5788 HD DSNG Encoder Page 1-7
ST.RE.E10137.3
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An internal frame synchroniser (see Internal Frame Synchroniser on
Page 1-8)
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Support for Active Format Descriptor (AFD)
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Support for a variety of Group of Pictures (GOP) structures with a
variable number of B frames
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Built-in patented adaptive noise reduction circuitry
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A logo overlay facility whereby the Encoder is able to overlay
broadcasters trademarks/logos onto the active video
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The ability to generate internal video test patterns. These can be
moving, with the ability to load two frames (SD only)
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With software option M2/ESO2/HD-MPASS enabled, a multi-pass
encoding mode is available which results in more efficient use of
bandwidth
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Support for ZigZag scan which statistically produces the same or more
efficient coding on most slow moving material
Motion Estimation
For SD fully Exhaustive motion estimation is used. It takes a macro block
of 16 pixels x 16 pixels and then performs an exhaustive search without
subsampling.
For HD a hierarchical motion estimation scheme is used. It creates a
hierarchical set of pictures, each layer containing a vertically and
horizontally sub-sampled version of the picture in the layer above. The
motion estimation search begins in the lowest layer that contains the
coarsest image. An exhaustive search of this layer produces an initial
location for the best match.
This location is then used as the start point for an exhaustive search in the
next layer up in the hierarchy. This higher layer image is more detailed, so
the new search acts to refine the previous search to produce a more
accurate location for the best match.
This process of locating the best match, then exhaustively re-searching
about this location in a higher layer is repeated until all the available
layers have been searched. The final search is in the original full resolution
image and is at ½ picture element (pel) accuracy.
Variable Video Bit-rate
The MPEG-2 compression algorithm uses adaptive field/frame coding,
forward and backward predictive processing with motion estimation and
compensation to reduce the bit-rate to the range shown in Table 1.3.
Table 1.3: Video Bit-rate Range
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Video Encoding Mode
4:2:0 (SD) 4:2:0 (HD) 4:2:2 (SD) 4:2:2 (HD)
0.256 Mbit/s - 15 Mbit/s 6 Mbit/s - 90 Mbit/s
For 480 and 576 the
minimum is 2 Mbit/s 2 Mbit/s - 50 Mbit/s 6 Mbit/s - 90 Mbit/s
For 480 and 576 the minimum is
2 Mbit/s
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Noise reduction is only available when software option M2/ESO2/NR or M2/ESO2/HDNR is purchased.
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The video bit-rate depends on the Multiplexer bit-rate which is set.