Zynq UltraScale+ MPSoC VCU TRD 2020.1 - SDI Video Capture

Owned by Ronak Shah (Unlicensed)
Last updated: Jul 13, 2020 by Sunil Vaghela
10 min read

This page provides all the information related to Design Module 8 - SDI Video Capture design.

Table of Contents

1 Overview

The primary goal of this Design is to demonstrate the capabilities of VCU hard block present in Zynq UltraScale+ EV devices. The TRD will serve as a platform to tune the performance parameters of VCU and arrive at optimal configurations for encoder and decoder blocks. 

This design supports the following video interfaces:

Sources:

  • SDI-Rx capture pipeline implemented in the PL.

  • File sink (SD card, USB storage, SATA hard disk).

  • Stream-Out from network or internet.

VCU Codec:

  • Video Encode/Decode capability using VCU hard block in PL 

    • AVC/HEVC encoding

    • Encoder/decoder parameter configuration.

Streaming Interfaces:

  • 1G Ethernet PS GEM 

Video Format:

  • XV20

Supported Resolution:

The table below provides the supported resolution from GUI and command-line app in this design.

Resolution

GUI

Command Line

Single Stream

Single Stream

4Kp60

X

√

4Kp30

X

√

1080p60

X

√

√ - Supported
x – Not supported

The below table gives information about the features supported in this design. 

Pipeline

Input source

Output Type

Resolution

VCU codec

Pipeline

Input source

Output Type

Resolution

VCU codec

Single Stream: Record/Stream-Out pipeline

SDI-Rx

File Sink/ Stream-Out

4K/1080p

HEVC/AVC

The below figure shows the SDI Video Capture design hardware block diagram.

The below figure shows the SDI Video Capture design software block diagram.

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 below link to download all TRD contents.

TRD package contents specific to SDI Video Capture design are placed in the following directory structure. The user needs to copy all the files from the $TRD_HOME/images/vcu_sdirx/ to FAT32 formatted SD card directory.

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

TRD package contents specific to VCU SDI Display design are placed in the following directory structure.

rdf0428-zcu106-vcu-trd-2020-1 ├── apu │ └── vcu_petalinux_bsp │ └── xilinx-vcu-zcu106-v2020.1-final.bsp ├── images │ ├── vcu_sdirx │ │ ├── autostart.sh │ │ ├── BOOT.BIN │ │ ├── boot.scr │ │ ├── config │ │ ├── image.ub │ │ ├── system.dtb │ │ └── vcu ├── pcie_host_package ├── pl │ ├── constrs │ ├── designs │ │ ├── zcu106_sdirx │ ├── prebuild │ │ ├── zcu106_sdirx │ ├── README.md │ └── srcs │ ├── hdl │ └── ip └── README.txt

configuration files (input.cfg) for various Resolutions are placed in the following directory structure in /media/card.

config ├── 4kp60 │ ├── Record │ └── Stream ├── 4kp30 │ ├── Record │ └── Stream ├── 1080p60 │ ├── Record │ └── Stream └── 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.

Execution of the application is shown below:

Example:

4kp60 HEVC_HIGH Record Pipeline execution

4kp60 HEVC_HIGH Stream-out Pipeline execution

Make sure SDI-Rx should be configured to 4kp60 mode.

Latency Measurement: To measure the latency of the pipeline, run the below command. The latency data is huge, so dump it to a file.

Refer below link for detailed run flow steps

1.3 Build Flow

Refer below link for build flow

2 Other Information

2.1 Known Issues

2.2 Limitations

2.3 Optimum VCU Encoder parameters for use-cases:

Video streaming:

  • Video streaming use-case requires a 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.

Performance: AVC Encoder settings:

  • It is preferred to use 8 or higher slices for better AVC encoder performance

  • AVC standard does not support Tile mode processing which results in the processing of MB rows sequentially for entropy coding

Quality: Low bitrate AVC encoding:

  • 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 bitrate

3 Appendix A - Input Configuration File (input.cfg)

The example configuration files are stored at /media/card/config/ folder.

Common Configuration:
It is the starting point of common configuration.

Num of Input:
Provide the number of inputs. this is always 1 for this design.

Output:
Select the video interface.
Options: DP

Out Type:
Options: record and stream

Display Rate:
Pipeline frame rate.
Options: 30 FPS or 60 FPS for each stream.

Exit:
It indicates to the application that the configuration is over.

Input Configuration:
It is the starting point of the input configuration.

Input Num:
Starting Nth input configuration.
Options: 1

Input Type:
Input source type.
Options: SDI

Uri:
File path. Applicable for file playback only. Supported file formats for playback are ts, mp4, and mkv.
e.g. file:///media/usb/abc.ts

Raw:
To tell the pipeline is processed or pass-through.
Options: True, False

Width:
The width of the live source.
Options: 3840, 1920

Height:
The height of the live source.
Options: 2160, 1080

Format:
The format of input data.
Options: XV20

Exit:
It indicates to the application that the configuration is over.

Encoder Configuration:
It is the starting point of encoder configuration.

Encoder Num:
Starting Nth encoder configuration.
Options: 1.

Encoder Name:
Name of the encoder.
Options: AVC, HEVC

Profile:
Name of the profile.
Options: baseline, main or high for AVC. Main for HEVC.

Rate Control:
Rate control options.
Options: CBR, VBR, and low-latency.

Filler Data:
Filler Data NAL units for CBR rate control.
Options: True, False

QP:
QP control mode used by the VCU encoder.
Options: Uniform or Auto

L2 Cache:
Enable or Disable L2Cache buffer in encoding process.
Options: True, False

Latency Mode:
Encoder latency mode.
Options: normal, sub_frame

Low Bandwidth:
If enabled, decrease the vertical search range used for P-frame motion estimation to reduce the bandwidth.
Options: True, False

Gop Mode:
Group of Pictures mode.
Options: Basic, low_delay_p, low_delay_b

Bitrate:
Target bitrate in Kbps
Options: 1-60000

B Frames:
Number of B-frames between two consecutive P-frames
Options: 0-4

Slice:
The number of slices produced for each frame. Each slice contains one or more complete macroblock/CTU row(s). Slices are distributed over the frame as regularly as possible. If slice-size is defined as well more slices may be produced to fit the slice-size requirement
Options:
4-22 4Kp resolution with HEVC codec
4-32 4Kp resolution with AVC codec
4-32 1080p resolution with HEVC codec
4-32 1080p resolution with AVC codec

GoP Length:
The distance between two consecutive I frames
Options: 1-1000

GDR Mode:
It specifies which Gradual Decoder Refresh(GDR) scheme should be used when gop-mode = low_delay_p
Options: Horizontal, Vertical, Disabled

GDR mode is currently supported with LLP1/LLP2 low-delay-p use-cases only

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. 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

It works in CBR/VBR rate-control only

Preset:
Options: HEVC_HIGH, HEVC_MEDIUM, HEVC_LOW, AVC_HIGH, AVC_MEDIUM, AVC_LOW, Custom

Exit
It indicates to the application that the configuration is over.

Record Configuration:
It is the starting point of record configuration.

Record Num:
Starting Nth record configuration.
Options: 1

Out File Name:
Record file path.
e.g. /media/usb/abc.ts

Duration:
Duration in minutes.
Options: 1-3

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

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

Exit
It indicates to the application that the configuration is over.

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.

4 Appendix B - SDI-Rx Link-up and GStreamer Commands

This section covers configuration of SDI-Rx using media-ctl utility, along with demonstrating SDI-Rx link-up issue and steps to switch SDI-Rx resolutions. It also contains sample GStreamer SDI Video pipelines for Record and Stream-out use-cases.

  • Run the below command to check the SDI link status and output format of the SDI input source.

If the SDI-Rx link has an issue, it appears as below.

  • Follow the below steps to switch the SDI-Rx resolution from 1080p60 to 4kp60.

    • Check current SDI Input Source Resolution (1080p60) by following the above-mentioned steps.

    • Run vcu_gst_app for current SDI resolution (1080p60) by executing the following command.

  • Below configurations needs to be set in input.cfg for SDI-1080p60.

  • Change Resolution of SDI Input Source from 1080p60 to 4kp60 by following the below steps

    • Set the SDI source resolution to 4kp60 (Homepage → settings → display & Sound → Resolution → change to 4kp60)

    • Save the configuration to take place the change

  • Verify desired SDI Input Source Resolution (4kp60) by following the above-mentioned steps

  • Record use case: Run the following gst-launch-1.0 command to record SDI video using the GStreamer pipeline

  • Stream-out use case: Run the following gst-launch-1.0 command to stream-out SDI video using the GStreamer pipeline.

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