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Appendices : MPEG Settings (MainConcept Encoder) Page 254
This option is only valid for MPEG-2.
Video Format: This setting is just a flag in the bitstream to inform the decoder how the pictures were represented
before encoding. If the sequence display header is not present, the decoder will assume "Unspecified video for-
mat". This setting does not affect the encoding process at all. It is part of the sequence display extension and is
only used when the Sequence display extension setting is 1. See ISO/IEC 13818-2. This option is only valid for
MPEG-2.
Color Primaries: This field specifies the x, y chromaticity coordinates of the source picture primaries. It is strictly
an informative flag to the video decoder and does not affect the video encoding at all. DVD specifies a value of 2
(ITU-R BT.470-2 System M) or 4 (SMTPE 170M) for NTSC or 3 (ITU-R BT.470-2 System B,G) for PAL. See ISO/IEC 13818-
2. This option is only valid for MPEG-2.
Transfer Characteristics: This field specifies the opto-electronic transfer characteristics of the source picture. It is
strictly an informative flag to the video decoder and does not affect the video encoding at all. DVD specifies a
value of 2 (ITU-R BT.470-2 System M) or 4 (SMTPE 170M) for NTSC or 3 (ITU-R BT.470-2 System B,G) for PAL. See ISO/
IEC 13818-2. This option is only valid for MPEG-2.
Matrix Coefficients: This field specifies the matrix coefficients used in deriving luminance and chrominance sig-
nals from the green, blue, and red primaries when RGB =>YUV conversion (if any) is done. DVD specifies a value of
3 (ITU-R Rec. 624-4 System B, G) for both NTSC and PAL. Currently only a value 3 is supported regardless of the set-
ting of this field. See ISO/IEC 13818-2. This option is only valid for MPEG-2.
Display Size: These values specify a rectangle which may be used by decoders as their active display area. MPEG
itself does not define what these values are actually used for, so it is up to the decoders to handle as they see fit.
DVD does define uses for these values, and the values should be 720x480 (NTSC) or 720x576 (PAL). These settings
are part of the sequence display extension and are only used when the Sequence display extension setting is 1.
Use the options Horizontal and Vertical to specify the exact value. See ISO/IEC 13818-2. This option is only valid for
MPEG-2.
The DVD specification does specify the values to use for the Color primaries, Transfer characteristics, Display hori-
zontal size and Display vertical size settings, if the SDE is present.
Under Picture Header the encoder offers one more setting:
Force VBV Delay: Set to 1 to have the VBV delay in the picture headers fixed to a value of 0xFFFF. Normally this is
1 when doing VBR encoding and 0 when doing CBR encoding. When the VBV delay is 0xFFFF a different method is
used to input data to the VBV than if VBV delay is not fixed to 0xFFFF. See ISO/IEC 13818-2 or ISO/ IEC 11172-2 .
The option Picture Coding Extension offers several additional settings:
Intra DC Precision: Specifies the effective precision of the DC coefficients in intra-coded macroblocks. 10-bits
usually achieves quality saturation, 11-bits can be used if the quantization is very low (the bitrate is quite high
compared to the frame size/rate). See ISO/IEC 13818-2. This option is only valid for MPEG2.
Use Frame Prediction and Frame DCT: Set to 1 to have the motion estimation and DCT (Discrete Cosine Transfor-
mation) computations done on both fields of a frame in the same pass, set to 0 to have them done on each field
independently. Normally this should be 0 for interlaced frames and 1 for progressive frames. Setting this field to 1
will result in slight faster encoding but will yield less quality in interlaced frames. This setting can be specified
independently for each frame type (I, B and P). See ISO/IEC 13818-2 section. This option is only valid for MPEG-2.
Quantization Scale Type: Specifies which mapping to use between the encoded quantization scale factor and
the quantizer scale applied in the inverse quantization arithmetic. Set to 0 to specify a linear mapping or 1 to spec-
ify a non-linear mapping. This setting can be specified independently for each frame type (I, B and P). See ISO/IEC
13818-2 section 6.3.10 for more information. This option is only valid for MPEG-2.
Intra VLC Format: VLC is the acronym for Variable Length Coding. This option specifies one of two MPEG defined
variable length coding tables used for intra coded blocks. Table 1 is considered to be statistically optimized for
Intra coded pictures coded within the sweet spot range (e.g. 0.3 to 0.6 bit/pixel) of MPEG-2. Normally set to 1 for
MPEG-2 video, 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.
Use Alternate Scanning Pattern: Specify one of two entropy scanning patterns which define the order in which
quantized DCT coefficients are run-length coded. Set to 1 for the alternate scanning pattern or 0 for the zig-zag
scanning pattern. The alternate scanning pattern is considered to be better suited for interlaced video where