GStreamer ABR Ladder Application¶
Introduction¶
The /opt/xilinx/vvas/bin/vvas_xabrladder application is a command line utility which implements the GStreamer video transcoding pipeline described in the diagram below. This application expects an input video file (mp4 with H.264/H.265 or H.264/H.265 elementary stream) and produces 5 different H.264/H.265 elementary streams. The resolution of each output stream is configured using a JSON file (by default: /opt/xilinx/vvas/share/vvas-examples/abrladder.json). The output streams produced by this application are saved in the /tmp/ladder_outputs/ folder.
This application is installed through the xilinx-alveo-u30-gstreamer package. If this package is not present on your system, install it by following the steps described in the package feed page.
Note
This example supports only input files of type mp4 with H.264/H.265 elementary stream in it. No other formats are supported
Host System Requirement¶
Xilinx Video SDK
GStreamer 1.16.2
gst-plugins-good
gst-plugins-base
gst-plugins-bad
gst-libav
gstpbutils
Opensource GStreamer plugins to be verified after installation of above packages:
h264parse
h265parse
qtdemux
tee
filesink
filesrc
Usage¶
Below are the input parameters required to run the application.
Parameter |
Short Form |
Description |
|---|---|---|
|
|
device index
Type: int
Range: 0 to 31
Default: NA
Option: Mandatory
|
|
|
JSON file used to describe the configuration of the ABR ladder
Type: string
Range: NA
Default:
/opt/xilinx/vvas/share/vvas-examples/abrladder.jsonOption: Optional
|
|
|
Enables or disables lookahead functionality
Type: int
Range: 0 (disable), 1 (enable)
Default: 1
Option: Optional
|
|
|
Output codec type
Type: int
Range: 0 (H264), 1 (H265)
Default: NA
Option: Mandatory
|
|
|
Input file path name (mp4/elementary-stream)
Type: string
Range: NA
Default: NA
Option: Mandatory
|
|
|
Keyframe (IDR frame) insertion frequency in number of frames
Type: int
Range: NA
Default: 0
Option: Optional
|
JSON Usage¶
The json file provided with --json option allows user to specify the ladder configuration with init time and run time (dynamic) property setting for each ladder.
The default json file that showcase basic ladder configuration (without run time property) is shown below.
{
"log-level": 2,
"ladder": {
"sink":"filesink",
"outputs" :[
{
"height" : 720,
"width" : 1280,
"framerate" : 60
},
{
"height" : 720,
"width" : 1280,
"framerate" : 30
},
{
"height" : 480,
"width" : 848,
"framerate" : 30
},
{
"height" : 360,
"width" : 640,
"framerate" : 30
},
{
"height" : 160,
"width" : 288,
"framerate" : 30
}
]
}
}
An example json file that showcase run time property (dynamic_params) change is shown below.
{
"log-level": 2,
"ladder": {
"sink":"filesink",
"outputs" :[
{
"height" : 720,
"width" : 1280,
"framerate" : 60,
"b-frames" : 4,
"dynamic_params" :[
{
"frame" : 600,
"b-frames" : 2,
"bitrate" : 6000,
"min-qp" : 5,
"max-qp" : 25
},
{
"frame" : 1500,
"b-frames" : 0,
"bitrate" : 3000,
"min-qp" : 15,
"max-qp" : 37
}
]
},
{
"height" : 720,
"width" : 1280,
"framerate" : 30,
"b-frames" : 4,
"spatial-aq" : false,
"temporal-aq" : false,
"spatial-aq-gain" : 50,
"dynamic_params" :[
{
"frame" : 500,
"spatial-aq" : true,
"temporal-aq" : false,
"spatial-aq-gain" : 50
},
{
"frame" : 1500,
"spatial-aq" : true,
"temporal-aq" : true,
"spatial-aq-gain" : 50
}
]
},
{
"height" : 480,
"width" : 848,
"framerate" : 30,
"b-frames" : 4,
"dynamic_params" :[
{
"frame" : 1000,
"b-frames" : 2,
"spatial-aq" : false,
"temporal-aq" : true,
"spatial-aq-gain" : 50
},
{
"frame" : 1500,
"b-frames" : 4,
"bitrate" : 3000,
"spatial-aq" : true,
"temporal-aq" : true,
"spatial-aq-gain" : 75
}
]
},
{
"height" : 360,
"width" : 640,
"framerate" : 30,
"b-frames" : 4
},
{
"height" : 160,
"width" : 288,
"framerate" : 30,
"b-frames" : 4
}
]
}
}
The JSON entries are explained in table below.
JSON Key |
Description |
|---|---|
ladder |
Indicates configuration of output ladder
|
sink |
Sink plugin to use for the GStreamer pipeline
|
outputs |
Array containing each ladder’s init time and run time (dynamic) configuration.
Supported init time configuration for each ladder are:
height
width
framerate
h264-profile
h264-level
h265-profile
h265-level
The default values of these parameters can be referred from the application source file.
|
dynamic_params |
Array entries inside
outputs JSON key containing ladder parameters that can be changed at run time at specified frame number.Application expects entries in each ladder to be in ascending order of
frame number.Supported run time parameters are :
|
Examples¶
Below are example commands for the ABR ladder use case. The output files are stored in /tmp/ladder_outputs/ folder. Ensure that enough space is availabe in this folder.
Running one ABR ladder on one device with lookahead (enabled by default):
vvas_xabrladder --devidx 0 --codectype 0 --file <path to file>
The above command takes the input video file (mp4 with H.264/H.265 or H.264/H.265 elementary stream) and produces 5 different H.264/H.265 elementary streams based on the codec type provided (0 for H.264 and 1 for H.265) with the following resolutions: 720p60, 720p30, 480p30, 360p30 and 160p30.
Running one ABR ladder on one device without lookahead:
vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 0 --file <path to file>
The above command takes the input video file (mp4 with H.264/H.265 or H.264/H.265 elementary stream) and produces 5 different H.264/H.265 elementary streams based on the codec type provided (0 for H.264 and 1 for H.265) with the following resolutions: 720p60, 720p30, 480p30, 360p30 and 160p30.
Running one ABR ladder on one device with lookahead enabled, and using the short-form options:
vvas_xabrladder -i 0 -l 1 -c 0 -f <path to file>
Running two ABR ladders, mapping each ladder to a specific device using the devidx option:
vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 1 --file <path to file> vvas_xabrladder --devidx 1 --lookahead_enable 0 --codectype 1 --file <path to file>
Running four ABR ladders on one device, leveraging the devidx option to optimally leverage resources:
vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 1 --file <path to file> vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 1 --file <path to file> vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 1 --file <path to file> vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 1 --file <path to file>
The four ABR ladders above can also be run using the
examples/gstreamer/tutorials/14_gst_app_transcode_plus_scale.shscript:<path to script>/14_gst_app_transcode_plus_scale.sh 0 <path to file>
Running one ABR ladder to insert Key (IDR) frames every 30 frames:
vvas_xabrladder --devidx 0 --lookahead_enable 0 --codectype 1 --forcekeyframe 30 --file <path to input file>
Running one ABR ladder to dynamically change encoder and lookahead parameters:
vvas_xabrladder --json <path to json file with dynamic parameters configuration> --devidx 0 --codectype 1 --file <path to input file>