What bitrates are used for encoding and publishing?
The bitrates used by Phenix correspond to quality capabilities. Each set of bitrates is referred to as a “ladder.”
phenix-2019 - current default for contribution encoding; to remain on this ladder please contact Phenix
phenix-2020 - new default for cloud encoding (including content ingested via RTMP)
Streaming - used when the Streaming or OnDemand capabilities are selected (see the API documentation). Note that the bitrates and resolution are the same as the values in the other ladders, but with a resampled frame rate for the lowest resolutions.
All layers will use the same playout buffer value to avoid lip sync issues. The system always uses the maximum playout buffer value of any of the layers once it finalizes the layers.
For example, if the highest resolution for a content stream is ‘fhd’ when using the phenix-2020 ladder, all layers will use a playout buffer of 0.233 seconds.
Additional notes:
Phenix does not use b-frames when encoding content.
I-frame only (IFO) tracks are not currently supported.
Phenix 2019 Ladder
The frame rate for all layers is equal to the frame rate of the input content.
Layer Name | Resolution | Bitrate | Playout Buffer | Type |
|---|---|---|---|---|
uld | 144 | 80 | 0.033 | Static |
vld | 240 | 350 | 0.033 | Static |
ld | 360 | 520 | 0.033 | Dynamic |
sd | 480 | 830 | 0.033 | Dynamic |
hd | 720 | 1600 | 0.066 | Static |
fhd | 1080 | 3000 | 0.233 | Static |
xhd | 1080 | 5500 | 0.266 | Static |
uhd | 1080 | 8500 | 0.266 | Static |
Phenix 2020 Ladder
The frame rate for all layers is equal to the frame rate of the input content.
Layer Name | Resolution | Bitrate | Playout Buffer | Type |
|---|---|---|---|---|
uld | 144 | 80 | 0.033 | Static |
vvld | 144 | 192 | 0.033 | Dynamic |
vld | 240 | 350 | 0.033 | Static |
ld | 360 | 520 | 0.033 | Both |
sd | 480 | 830 | 0.033 | Both |
hd | 720 | 1600 | 0.066 | Static |
fhd | 1080 | 3000 | 0.233 | Static |
xhd | 1080 | 5500 | 0.266 | Static |
uhd | 1080 | 8500 | 0.266 | Static |
Streaming Ladders
The following table represents values used in phenix-2019.
In the Frame Rate Resampling column:
“2/1” indicates that the frame rate is half that of the frame rate of the input content.
“none” indicates the frame rate is equal to the frame rate of the input content.
ID | Quality | Resolution | Bitrate | Frame Rate Resampling |
|---|---|---|---|---|
qcif | uld | 144 | 80 | 2/1 |
sif | vld | 240 | 350 | 2/1 |
ld | ld | 360 | 520 | 2/1 |
sd | sd | 480 | 830 | none |
hd | hd | 720 | 1600 | none |
fhd | fhd | 1080 | 3000 | none |
xhd | xhd | 1080 | 5500 | none |
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