2 Other Information

2.1 Known Issues

• For Petalinux related known issues please refer AR# 72950: PetaLinux 2019.2 - 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 Petalinux related limitations please refer AR# 72950: PetaLinux 2019.2 - 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 AnchorPG252 2019.2PG252 2019.2PG252 link.

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 slices only 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:
1, 2

Output:
Select the video interface.
Options: HDMI

Out Type:
Options: display 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, 2

Input Type:
Input source type.
Options: HDMI

Raw:
To tell the pipeline is processed or pass-through.
Options: False
Note: Raw use-case is not supported for LLP2 use-case. It is supported for non-LLP2 use-case.

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

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

root@zcu106_vcu_trd:~# xmedia-ctl -p -d /dev/media1 -----> media node for HDMI input source
Media controller API version 4.19.0

Media device information
------------------------
driver          xilinx-video
model           Xilinx Video Composite Device
serial          
bus info        
hw revision     0x0
driver version  4.19.0

Device topology
- entity 1: vcap_hdmi output 0 (1 pad, 1 link)
            type Node subtype V4L flags 0
            device node name /dev/video0 -----> Video node for HDMI Rx source
        pad0: Sink
                <- "a0080000.v_proc_ss":1 [ENABLED]

- entity 5: a0080000.v_proc_ss (2 pads, 2 links)
            type V4L2 subdev subtype Unknown flags 0
            device node name /dev/v4l-subdev1
        pad0: Sink
                [fmt:VYYUYY8_1X24/1280x720 field:none colorspace:srgb]
                <- "a0000000.v_hdmi_rx_ss":0 [ENABLED]
        pad1: Source
                [fmt:VYYUYY8_1X24/1920x1080 field:none colorspace:srgb]
                -> "vcap_hdmi output 0":0 [ENABLED]

- entity 8: a0000000.v_hdmi_rx_ss (1 pad, 1 link)
            type V4L2 subdev subtype Unknown flags 0
            device node name /dev/v4l-subdev2
        pad0: Source
                [fmt:RBG888_1X24/3840x2160 field:none colorspace:srgb]
                [dv.caps:BT.656/1120 min:0x0@25000000 max:4096x2160@297000000 stds:CEA-861,DMT,CVT,GTF caps:progressive,reduced-blanking,custom
]
                [dv.query:no-link] -----> HDMI Rx Link Status
                -> "a0080000.v_proc_ss":0 [ENABLED]

NOTE: Here "dv.query:no-link" under "v_hdmi_rx_ss" node shows HDMI-Rx source is not connected or HDMI-Rx source is not active(Try waking up the device by pressing a key on remote).

• Follow the below steps to switch the HDMI-Rx resolution from 1080p60 to 4kp60.
  • Check current HDMI Input Source Resolution (1080p60) by following the above-mentioned steps.
  • Run vcu_gst_app for current HDMI resolution (1080p60) by executing the following command.

$ vcu_gst_app /media/card/config/input.cfg

Below configurations needs to be set in input.cfg for non-LLP2 HDMI-1080p60 use-case.

Common Configuration    : START
Num Of Input            : 1
Output                  : HDMI
Out Type                : Display
Frame Rate              : 60
Exit

Input Configuration     : START
Input Num               : 1
Input Type              : hdmi_1
Raw                     : FALSE
Width                   : 1920
Height                  : 1080
Format                  : NV12
Enable LLP2             : FALSE
Exit

Encoder Configuration   : START
Encoder Num             : 1
Encoder Name            : HEVC
Profile                 : Main
Rate Control            : Low_Latency
Filler Data             : False
QP                      : Auto
L2 Cache                : TRUE
Latency Mode            : Sub_Frame
Low Bandwidth           : FALSE
Gop Mode                : Basic
Bitrate                 : 25000
B Frames                : 0
Slice                   : 8
GoP Length              : 60
Preset                  : Custom
Exit

• • Change Resolution of HDMI Input Source from 1080p60 to 4kp60 by following below steps.
    • Set the HDMI source resolution to 4kp60 (Homepage → Settings → Display & Sound → Resolution → change to 4kp60).
    • Save the configuration to take place the change.
  • Verify the desired HDMI Input Source Resolution (4kp60) by following the above-mentioned steps.

• If HDMI Tx link-up issue is observed after Linux booting, use the following command to get the blue screen on HDMI-Tx for 4kp60.

% modetest -D a0070000.v_mix -s 35:3840x2160-60@BG24

• The table below lists the parameters of the pixel format.

• Run the following gst-launch-1.0 command to display NV12 video on HDMI-Tx using ultra low-latency(LLP2) GStreamer pipeline (capture → encode → decode → display). Where "video0" indicates a video node for the input source.

$ gst-launch-1.0 v4l2src io-mode=4 device=/dev/video0 ! video/x-raw\(memory:XLNXLL\), width=3840, height=2160, format=NV12, framerate=60/1 ! omxh265enc qp-mode=auto gop-mode=basic gop-length=60 b-frames=0 target-bitrate=25000 num-slices=8 control-rate=low-latency prefetch-buffer=TRUE low-bandwidth=false filler-data=0 cpb-size=1000 initial-delay=500 ! video/x-h265, alignment=nal ! queue max-size-buffers=0 ! omxh265dec low-latency=1 ! video/x-raw\(memory:XLNXLL\) ! queue max-size-bytes=0 ! fpsdisplaysink name=fpssink text-overlay=false video-sink="kmssink bus-id=a0070000.v_mix plane-id=30 max-lateness=5000000 show-preroll-frame=false sync=true" sync=true

• Run the following gst-launch-1.0 command to stream-out NV12 video using ultra low-latency(LLP2) GStreamer pipeline. Where "video0" indicates a video node for the input source.