INS_CNVETX1_REV– 06/10/13 PAGE 57
INSTALLATION AND OPERATION MANUAL
CNVETX1
TECH SUPPORT: 1.888.678.9427
To set the MPEG-2 Video CODEC:
1. In the left pane select the Streaming menu, and from the sub-menus select Video and then
MPEG-2.
The right pane displays the MPEG-2 Parameters area.
2. In the GOP Size text-box select the number of frames in a GOP (Group of Pictures) in the range
of 1–1000.
3. From the Rate Control Mode drop-down list select the rate control mode for the MPEG-2
encoder. The default is CBR.
›
CBR (Constant Bit Rate)
›
Constant Q (Constant Quantization)
4. Enter the required bit rate parameter according to the rate control mode (between 50000 to
10000000):
›
CBR: the constant bit rate of the video stream. The default is 5000000
5. Enter the required Q parameters:
›
CBR:
Q Min: minimum quantization value. The default is 1.
Q Max: maximum quantization value. The default is 112.
›
Constant Q:
Q Initial: constant quantization value. The default is 20.
Configuring the H.264 Video CODEC
You can set the H.264 video CODEC settings of GOP Size, Rate Control Mode, Average Bit Rate,
Maximum Bit Rate, Q Max, Q Min, 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 key frames (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 H.264 encoder. The
options are CBR and VBR and Constant_Q.
In CBR encoding the bit rate is kept constant and is useful for streaming multimedia content on
limited capacity channels.
VBR files vary the amount of output data per time segment. VBR allows a higher bit rate (and
therefore more storage space) to be allocated to the more complex segments of media files while
less space is allocated to less complex segments. The average of these rates can be calculated to
produce an average bit rate for the file.
