CONFIDENTIAL
Z3-DM8168-PCI-RPS V1.05.01c
___________________________________________________________________________________________
Z3 Technology, LLC
♦
100 N 8
th
ST, STE 250
♦
Lincoln, NE 68508-1369 USA
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+1.402.323.0702
18
5.9 Showing encode passthrough on a screen (Optional)
To see what is being encoded on a monitor, simply connect that monitor to HDMI Out of the Z3-DM8168-
PCI-RPS (see
Figure 10
). Once you do this, you should see the video going into the encoder on the monitor.
5.10 Adjusting for latency and quality
For latency, the key parameters to work with are Video Burst Size and B-frame Interval.
Video Burst Size defines the number of milliseconds of buffering the encoder has to work with. The higher
this value, the more buffers it has to work with and the more time it has to “smooth things out” for
challenging content. However, a higher value also causes latency to increase accordingly. To minimize
latency, this value should be set to the lowest possible value. The lowest value Z3 recommends is 150.
B-frames improve the quality of the picture, but they also increase the latency by 1 frame time. To
minimize latency, the number of B-frames should be set to 0 (B-frame Interval should be set to “1”).
Figure 11
shows the suggested values for Video Burst Size and B-frame Interval for 3 common use cases:
Video Burst Size
B-frame
Interval
Case 1: Highest Quality, Highest Latency
2000
3
Case 2: Good Quality, Standard Latency
1000
2
Case 3: Normal Quality, Lowest Latency
150
1
Figure 11 Tuning for Various Use Cases
HDMI
Out
Figure 10 HDMI Out to Show Encode Passthrough
