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Appendices : MPEG Settings (MainConcept Encoder) Page 255
sophisticated forward quantization is not enabled. This setting can be specified independently for each frame
type (I, B and P). See ISO/IEC 13818-2. This option is only valid for MPEG-2.
The General option offers two more parameters you can change:
Sequence End Code: If set to 1 a sequence end code is written at the end of the video stream (it terminates the
stream). Normally this is set to 1, set to 0 if you intend to concatenate video streams together after encoding. See
ISO/IEC 13818-2 section 6.3.2 or ISO/IEC 11172-2.
Embed SVCD User Blocks: If set to 1, user data blocks are placed in the bitstream to reserve space for the SVCD
scan information data. The multiplexer then fills in the correct values when the video stream is muxed. Should
only be enabled for SVCD video, but disabled for non-standard SVCD video.
Under Rate Control you find the following options:
The options Reaction Parameter, Initial Average Activity, Initial Global Complexity Measure and Initial Virtual Buf-
fer Fullness are very complex as well as highly mathematical. These values are default to 0 and should not be
changed unless advised to do so by MainConcept support.
Minimum Frame Percentage: This option is basically the target number of bits (as a percentage of the VBV size)
for the first frame in the stream.
Pad Frame Percentage: This function is used when the VBR bitrate drops below the specified minimum bitrate. It
is only applicable for VBR; if this field is 0 no padding occurs and the minimum bitrate is permitted to drop below
the specified minimum. If the field is 100, the stream is padded to keep the minimum bitrate near the specified
minimum.
Motion Estimation offers the following options:
• P Frame Motion Vector
• Forward Search Width
• Forward Search Height
• B Frame Motion Vectors
• Forward Search Width
• Forward Search Height
• Backward Search Width
• Backward Search Height
The search width and height settings set the (half ) width of the window used for motion estimation. Here is an
example of how to set these values, assuming a maximum motion of 10 pixels per frame in horizontal direction
and 5 pixels per frame in the vertical direction and M = 3 (I B1 B2 P). Table 1: Search Width and Height values
The search window settings are +/- values, for instance if a search window value is 10, the actual search for a
matching pixel is done from (x + 10, y) to (x - 10, y) for each pixel (x, y).
These values are usually set automatically by either the Video encoder quality sliders (Search method and Search
range) or the Motion search pixel movement settings but can be set manually here.
Forward Horizontal Vertical Backward Horizontal Vertical
I > B1 10 5 B1 > P 20 10
I > B2 20 10 B2 > P 10 5
I > P 30 15