INS_CNVETX1_REV– 06/10/13 PAGE 54
INSTALLATION AND OPERATION MANUAL
CNVETX1
TECH SUPPORT: 1.888.678.9427
5. Enter the required Q parameters. The range of QInitial is 8 to 30.
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CBR:
Q Initial: initial quantization value. The default is 8
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CONSTANT_Q:
Q Initial: initial quantization value. The default is 8
Configuring the MPEG-2 Video CODEC
You can set the MPEG-2 video CODEC settings of GOP Size, Rate Control Mode, Average Bit rate,
Maximum Bit rate, Bit rate and Q Initial.
GOP Size
In order to allow high compression rates for digital video it may be encoded into GOPs, or Groups
of Pictures, which consist of keyframes (I-Frames) and delta frames (P or B Frames). The Group of
Pictures GOP Size defines the distance between consecutive I-Frames in a video stream.
Rate Control Mode
The Rate Control Mode parameter defines Rate control options for the MPEG-2 encoder. The
options are CBR and Constant Q.
In CBR encoding the bit rate is kept constant and is useful for streaming multimedia content on
limited capacity channels.
In Constant Q mode only Q Initial is entered. This mode is intended to keep a constant quality.
A low Q setting will generally have a high bit rate providing high quality. A high Q setting will
generally have a low bit rate with lower quality.
Each mode has its own relevant parameters. Other parameters are shaded.
Bit rate
The Bit rate parameter is the bit rate of the stream. The Bit rate can be set to a value in the range
of 50000 to 10000000. The default value is 5000000.
The rate control mode determines the required parameters.
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Constant Bit rate: The bit rate of the video stream (CBR mode only).
