This page provides all the information related to Design Module 12 - VCU TRD Xilinx low latency(LLP2) PL DDR NV16 HDMI design.
Table of Contents
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1 Overview
This module enables capture of video from an HDMI-Rx subsystem implemented in the PL. The video can be displayed through the HDMI-Tx subsystem implemented in the PL. The module can stream-out and stream-in live captured video frames through an Ethernet interface at ultra-low latencies using Sync IP. This module supports multi-stream for NV16 pixel format. In this design PL_DDR is used for decoding and PS_DDR for encoding so that DDR bandwidth would be enough to support high bandwidth VCU applications requiring simultaneous encoder and decoder operations and transcoding at 4k @60 FPS.
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The table below provides the supported resolution from command line app only in this design.
Resolution | Command Line | |
Single Stream | Multi-stream | |
4kp60 | √ | NA |
4kp30 | √ | √ (Max 2) |
1080p60 | √ | √ (Max 4 for encoder) (Max 2 for decoder) |
√ - Supported
NA – Not applicable
x – Not supported
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The below figure shows the Xilinx Low Latency PL DDR NV16 HDMI design software block diagram.
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1.1 Board Setup
Refer below link for Board Setup
1.2 Run Flow
The TRD package is released with the source code, Vivado project, Petalinux BSP, and SD card image that enables the user to run the demonstration. It also includes the binaries necessary to configure and boot the ZCU106 board. Prior to running the steps mentioned in this wiki page, download the TRD package and extract its contents to a directory referred to as ‘TRD_HOME' which is the home directory.
Refer Section 4.1 : Download the TRD of
Zynq UltraScale+ MPSoC VCU TRD 2020.1wiki page to download all TRD contents.
TRD package contents are placed in the following directory structure. The user needs to copy all the files from the $TRD_HOME/images/vcu_llp2_hdmi_nv16/ to FAT32 formatted SD card directory.
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rdf0428-zcu106-vcu-trd-2020.-1 ├── apu │ └── vcu_petalinux_bsp ├── images │ ├── vcu_10g │ ├── vcu_audio │ ├── vcu_hdmi_multistream_xv20 │ ├── vcu_hdmi_rx │ ├── vcu_hdmi_tx │ ├── vcu_llp2_hdmi_nv12 │ ├── vcu_llp2_hdmi_nv16 │ ├── vcu_llp2_hdmi_xv20 │ ├── vcu_llp2_sdi_xv20 │ ├── vcu_multistream_nv12 │ ├── vcu_pcie │ ├── vcu_sdirx │ ├── vcu_sditx │ └── vcu_sdi_xv20 ├── pcie_host_package │ ├── COPYING │ ├── include │ ├── libxdma │ ├── LICENSE │ ├── readme.txt │ ├── RELEASE │ ├── tests │ ├── tools │ └── xdma ├── pl │ ├── constrs │ ├── designs │ ├── prebuild │ ├── README.md │ └── srcs └── README.txt |
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rdf0428-zcu106-vcu-trd-2020.-1 ├── apu │ └── vcu_petalinux_bsp │ └── xilinx-vcu-zcu106-v2020.1-final.bsp ├── images │ ├── vcu_llp2_hdmi_nv16 │ │ ├── autostart.sh │ │ ├── bin │ │ ├── BOOT.BIN │ │ ├── boot.scr │ │ ├── config │ │ ├── image.ub │ │ ├── system.dtb │ │ └── vcu ├── pcie_host_package ├── pl │ ├── constrs │ ├── designs │ │ ├── zcu106_llp2_nv16 │ ├── prebuild │ │ ├── zcu106_llp2_nv16 │ ├── README.md │ └── srcs │ ├── hdl │ └── ip └── README.txt |
Configuration files(input.cfg) for various resolutions are placed in the following directory structure in /media/card.
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config/
├── 1-4kp60
│ ├── Display
│ └── Stream-out
├── 2-1080p60
│ ├── Display
│ └── Stream-out
├── 2-4kp30
│ ├── Display
│ └── Stream-out
└── 4-1080p60
│ └── Stream-out
└── input.cfg |
1.2.1 GStreamer Application (vcu_gst_app)
The vcu_gst_app is a command line multi-threaded linux application. The command line application requires an input configuration file (input.cfg) to be provided in the plain text.
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1.3 Build Flow
Refer below link for detailed build flow steps:
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2 Other Information
2.1 Known Issues
For Petalinux related known issues please referAR# 72950: PetaLinux 2020.1 - Product Update Release Notes and Known IssuesLink will be added <June-05>.
For VCU related known issues please refer AR# 66763: LogiCORE H.264/H.265 Video Codec Unit (VCU) - Release Notes and Known Issues and Xilinx Zynq UltraScale+ MPSoC Video Codec Unit.
2.2 Limitations
For Petalinux related limitations please referAR# 72950: PetaLinux 2020.1 - Product Update Release Notes and Known IssuesLink will be added <June-05>.
For VCU related limitations please refer AR# 66763: LogiCORE H.264/H.265 Video Codec Unit (VCU) - Release Notes and Known Issues , Xilinx Zynq UltraScale+ MPSoC Video Codec Unit and PG252 Link will be added <June-05>.
2.3 Optimum VCU Encoder parameters for use-cases
Video streaming:
Video streaming use-case requires very stable bitrate graph for all pictures.
It is good to avoid periodic large Intra pictures during the encoding session
Low-latency rate control (hardware RC) is the preferred control-rate for video streaming, it tries to maintain equal amount frame sizes for all pictures.
Good to avoid periodic Intra frames instead use low-delay-p (IPPPPP…)
VBR is not a preferred mode of streaming.
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Enable profile=high and use qp-mode=auto for low-bitrate encoding use-cases.
The high profile enables 8x8 transform which results in better video quality at low bitrates.
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3 Appendix A - Input Configuration File (input.cfg)
The example configuration files are stored at /media/card/config/ folder.
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Entropy Mode:
It specifies the entropy mode for H.264 (AVC) encoding process
Options: CAVLC/CABAC/Default
Max Picture Size:
It is used to curtail instantaneous peak in the bit-stream using this parameter. It works in CBR/VBR rate-control only. When it is enabled, max-picture-size value is calculated and set with 10% of AllowedPeakMargin. i.e. max-picture-size = (TargetBitrate / FrameRate) * 1.1.
Options: TRUE/FALSE
Preset:
Options: Custom
Exit:
It indicates to the application that the configuration is over.
Streaming Configuration:
It is the starting point of streaming configuration.
Streaming Num:
Starting Nth Streaming configuration.
Options: 1, 2, 3, 4
Host IP:
The host to send the packets to
Options: 192.168.25.89 or Windows PC IP
Port:
The port to send the packets to
Options: 5004, 5008, 5012 and 5016
Trace Configuration:
It is the starting point of trace configuration.
FPS Info:
To display fps info on the console.
Options: True, False
APM Info:
To display APM counter number on the console.
Options: True, False
Pipeline Info:
To display pipeline info on console.
Options: True, False
Exit:
It indicates to the application that the configuration is over.
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4 Appendix B - HDMI-Rx/Tx Link-up and GStreamer Commands
This section covers configuration of HDMI-Rx using media-ctl utility and HDMI-Tx using modetest utility, along with demonstrating HDMI-Rx/Tx link-up issues and steps to switch HDMI-Rx resolution. It also contains sample GStreamer Low-Latency NV16 and Xilinx’s Ultra Low-Latency NV16 Video pipelines for Display, Stream-In and Stream-Out use-cases.
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The table below lists the parameters of the pixel format.
Pixel Format | GStreamer Format | Media Bus Format | GStreamer HEVC Profile | GStreamer AVC Profile | Kmssink Plane-id |
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NV16 | NV16 | UYVY8_1X16 | main-422 | high-4:2:2 | 33 and 34 |
Video0in the each gst-launch pipelines indicates a video node for the input source.Make sure HDMI-Rx should be configured to 4kp60 mode, while running below example pipelines.
LLP1/LLP2 stream-in pipelines are not supported using vcu_gst_app.
For LLP1/LLP2 Multi-stream HEVC serial and stream-out use-cases (2-4kp30, 2-1080p60, 4-1080p60), use
ENC_EXTRA_OP_BUFFERS=10variable before gst-launch-1.0 command.For LLP1/LLP2 Multi-stream serial and stream-in use-cases (2-4kp30, 2-1080p60, 4-1080p60), use
internal-entropy-buffers=3property in decoder.
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