Introduction to the Basic Encoder
Page 1-6
Reference Guide: evolution 5000 E5780 and E5782 Encoder
ST.RE.E10135.4
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 bitrate
The MPEG-2 compression algorithm uses adaptive field/frame coding, forward and backward
predictive processing with motion estimation and compensation to reduce the bitrate to the
range shown in
Table 1.3: Video bitrate 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
NOTE…
Lower bitrates can be achieved, in HD mode, when used in Statistical Multiplexing equipment.
Coding Resolutions
To provide optimum picture quality over the full range of supported bitrates, the encoded
picture resolution is controlled automatically according to the video bitrate. Alternatively, the
user can override this and select manual control, if desired. Coding resolutions are shown in
Annex B, Technical Specification
.
Internal Frame Synchroniser
An internal frame synchroniser is provided to accommodate slight differences between the
incoming frame rate and that generated by the stable reference
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used by the Encoder.
Output on Video Loss
The Encoder can be software-configured to show, in the event of video input loss, either:
•
A test pattern (with or without ident text) (SD only)
•
A freeze frame (with or without ident text) (SD only)
•
Display Stored OSD (Only available if the Encoder has an OSD loaded).
•
Cut to a black screen (HD default)
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The video bitrate depends on the Multiplexer bitrate which is set.
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To ensure broadcast quality it is recommended that the studio reference is fed to HYSNC.
