Zynq UltraScale+ MPSoC VCU TRD 2019.1 - SDI Video Capture


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.

Sinks:

  • 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
GUICommand Line
Single StreamSingle Stream
4kp60X
4kp30X
1080p60X

√ - Supported
NA – Not applicable
x – Not supported

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

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.

configuration files(input.cfg) for various Resolutions are placed in the following 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.

Execution of the application is shown below:


Example:

4kp60 HEVC_HIGH Record Pipeline execution

4kp60 HEVC_HIGH Stream-out Pipeline execution

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

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 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 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 input. 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.
Options: 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

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

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 Nth record configuration.
Options: 1

Out File Name:
Record file path.
Options: /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 Link Status

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

NOTE: Check resolution and frame-rate of "v_smpte_uhdsdi_rx_ss" node.

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

NOTE: Check resolution and frame-rate of "v_smpte_uhdsdi_rx_ss" node.

  • 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 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.
  • Run the following gst-launch-1.0 command to record SDI video using GStreamer pipeline.

NOTE: File location should be USB-3.0 to avoid the read-write bandwidth issue.

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

NOTE: Here 192.168.25.89 is host/client IP address and 5004 is port no.

  • Run the following gst-launch-1.0 command to stream-out low-latency SDI video using GStreamer pipeline.

Notes for gst-launch-1.0 commands:

  • Make sure SDI-Rx media pipeline is configured for 4kp60 resolution and source/sink have the same color format. Run below xmedia-ctl commands to set resolution and format of SDI scaler node.

When SDI Input Source is NVIDIA SHIELD or ABOX (using external HDMI to SDI converter)

NOTE: Make sure NVIDIA SHIELD or ABOX is configured for 4kp resolution and UYVY8 color format.