Encoding parameters that affect performance
You can tune the quality, speed, and density of the video encodes in each event.
CABAC
For information about this parameter, see Miscellaneous video tuning parameters.
Codec of the output encode
Some codecs make more demands on the CPU than other codes. Here is a comparison of the processing demands of codecs, from least to most demanding:
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JPEG XS
-
MPEG
-
AVC
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HEVC
For more information, see Controlling video quality.
Density versus quality (SVQ)
You can modify the density and quality balance of each individual encode by setting the Density vs Quality field. You can favor quality at the cost of density, or you can favor density at the cost of quality.
For more information, see Miscellaneous video tuning parameters.
Encode order
If you are using a version of AWS Elemental Live before version 2.24.4, AWS Elemental Live assigns CPU resources to the encodes (streams) in the order in which they appear in the web interface or in the XML of the event. You should list your video encodes (streams) from highest resolution to lowest resolution. In this way, Elemental Live will first assign CPU resources to the most difficult encodes.
Starting with version 2.24.4, Elemental Live automatically assigns resources to the most difficult encodes.
Frame rate, resolution, bitrate, and color depth
A key factor in performance is the pixels per second being produced by all outputs in all events.
The following characteristics of each video encode affect pixels per second:
| Characteristic | Field in the Video section of the Output section | Comment |
|---|---|---|
| Resolution | Resolution | |
|
Frame rate |
Frame Rate |
|
| Bitrate | Rate Control Mode | See Setting up QVBR and rate control mode. |
| Color depth: 8-bit or 10-bit | Part of the profile of the codec: Video Stream, then Advanced, then Profile |
Group of pictures
For more information, see Group of pictures (GOP) configuration.
Lookahead
For more information, see Miscellaneous video tuning parameters.
Quantization
For more information, see Quantization controls.
Slices
This parameter affects CPU usage.
The number of slices in each video frame affects the CPU usage. You must balance the desired quality against the processing demands of that quality.
We recommend that you set the slices to automatic, to let Elemental Live set the value that works best for the video resolution. For more information, see Miscellaneous video tuning parameters.
