This page provides all the information related to Design Module 1 - VCU TRD Muti Stream 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:

• Test pattern generator (TPG) implemented in the PL

• HDMI-Rx capture pipeline implemented in the PL

• MIPI CSI-2 Rx capture pipeline implemented in the PL

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

• Stream-In from network or internet

Sinks:

• DP-Tx display pipeline in the PS

• HDMI-Tx display pipeline implemented in the PL

VCU Codec:

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

  • AVC/HEVC encoding

  • Encoder/decoder parameter configuration.

  • Demonstrate the multi-stream capability of VCU at 4K 60 Hz throughput

Streaming Interfaces:

• 1G Ethernet PS GEM 

Video format:

• NV12

This design demonstrates the multi-stream capability of VCU at 4K 60 Hz throughput.

• Supports 2-4Kp30 multi-stream feature with any 2 of HDMI-Rx, TPG, and MIPI as the input source and HDMI-Tx as display pipeline.

• Supports 4-1080p60 multi-stream feature with 3 HDMI-Rx and 1 MIPI as the input source and HDMI-Tx as display pipeline.

• Supports 8-1080p30 multi-stream feature with 7 HDMI-Rx and 1 MIPI as the input source and HDMI-Tx as display pipeline.

Other features:

• This design supports 8 channel memory-based SCD(Scene Change Detection) IP. SCD can be enabled or disabled through configuration.

Supported Resolution:

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

√- Supported
x - Not supported
NA - Not applicable

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

The below figure shows the VCU TRD Multi Stream design hardware block diagram.

Open

The below figure shows the VCU TRD Multi Stream design software block diagram.

Open

1.1 Board Setup

Refer below link for Board Setup

• Zynq UltraScale+ MPSoC VCU TRD 2020.1 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.

• Refer Section 4.1 : Download the TRD of Zynq UltraScale+ MPSoC VCU TRD 2020.1 wiki 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_trd/ to FAT32 formatted SD card directory.

TRD package contents specific to VCU TRD Multi Stream design are placed in the following directory structure.

The below snippet shows the configuration files (input.cfg) for running various multistream Display, Record, and Streaming use cases. All these configurations files are placed in the images folder mentioned above. The directory structure in /media/card.

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.

Run below modetest command to set CRTC configurations for 4Kp60:

Run below modetest command to set CRTC configurations for 4Kp30:

Execution of the application is shown below:

Example:

4kp60 HEVC_HIGH Display Pipeline Execution

4kp60 HEVC_HIGH Record Pipeline Execution

4kp60 HEVC_HIGH Stream-out Pipeline Execution

4kp60 HEVC_HIGH Stream-in Pipeline Execution

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

• Zynq UltraScale+ MPSoC VCU TRD 2020.1 - Run Flow

1.3 Build Flow

Refer below link for detailed build flow steps

• Zynq UltraScale+ MPSoC VCU TRD 2020.1 - Build Flow

2 Other Information

2.1 Known Issues

• Frame drop observed in TPG pipeline

  • Frequency: Always

  • Workaround: None

• Frame drops to zero as Encoder/Decoder bandwidth goes to zero

  • Frequency: Rarely and Randomly observed

  • Workaround: None

• VCU QT: Green shade on DP when playing 4Kp30 HDMI/MIPI pipeline with SCD

  • Frequency: Always

  • Workaround: None

• For Petalinux related known issues please refer: PetaLinux 2020.1 - Product Update Release Notes and Known Issues

• 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 playback in DP, video input resolution should match to DP's native resolution. This constraint is due to the support of the GUI. In the GUI case if we allow video source other than native resolution(by setting full screen overlay) then the graphics layer will disappear. To recover back GUI user need to kill and relaunch the GUI app. To avoid such condition TRD only supports video input resolution which is equal to DP's native resolution.

• For Petalinux related limitations please refer: PetaLinux 2020.1 - Product Update Release Notes and Known Issues

• 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

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; as 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 bitrates

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. It is ranging from 1 to 8

Output:
Select the video interface
Options: HDMI or DP

Out Type:
Options: display, 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 N^th input configuration
Options: 1-8

Input Type:
Input source type
Options: TPG, HDMI, HDMI_2, HDMI_3, HDMI_4, HDMI_5, HDMI_6, HDMI_7, MIPI, File, Stream

Uri:
File path or Network URL. Applicable for file playback and stream-in pipeline only. Supported file formats for playback are ts, mp4, and mkv.
Options: file:///run/media/sda/abc.ts (for file path), udp://192.168.25.89:5004/ (for Network streaming, Here 192.168.25.89 is Client's IP address and 5004 is port number)

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: NV12

Enable SCD:
Enable or Disable Memory based SCD in the pipeline
Options: True, False

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

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

Encoder Num:
Starting N^th encoder configuration
Options: 1-8

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, 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

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

Format:
The format of input data
Options: NV12

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 N^th record configuration
Options: 1-8

Out-File Name:
Record file path
e.g. /run/media/sda/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 N^th Streaming configuration
Options: 1-8

Host IP:
The host to send the packets to the client
Options: 192.168.25.89 or Windows PC IP

Port:
The port to send the packets to
Options: 5004, 5008, 5012, 5016, 5020, 5024, 5028, and 5032

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 achieved frame per second information 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.

Mount Locations

The mount locations for various devices can be found in the below table.
The mount locations can vary.  Users can use lsblk or mount to find the location of the mounted devices.

Below are some example mount points

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 HDMI Video pipelines for Display, Record & Playback, Stream-in and Stream-out use-cases.

• Kill the Qt GUI application running on target board by executing the below commands from the serial console

• HDMI source can be locked to any resolution. Run the below command for all media nodes to print media device topology where "mediaX" represents different media nodes. In the topology, log look for the “v_hdmi_rx_ss” string to identify the HDMI input source media node.

• To check the link status, resolution and video node of the HDMI input source, run below media-ctl command where "mediaX" indicates media node for the HDMI input source.

• When HDMI source is connected to 4Kp60 resolution, it shows as below: