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AR# 72328

2019.1 Zynq UltraScale+ MPSoC VCU - Why is there initial "jerkiness" when transcoding with a 4Kp60 AVC pipeline?


Why is there initial "jerkiness" when transcoding with a 4Kp60 AVC pipeline?

The example below has 4Kp60 NV12 (8-bit 4:2:2) with B-Frames=0, and AVC Encode with a target bitrate of 10000kbps:

gst-launch-1.0 -v v4l2src device=/dev/video0 io-mode=4 ! video/x-raw,format=NV12,width=3840,height=2160, framerate=60/1 ! omxh265enc control-rate=2 gop-length=15 b-frames=0 target-bitrate=10000 periodicity-idr=120 prefetch-buffer=true   ! h265parse ! omxh265dec ! queue max-size-bytes=0 !  fpsdisplaysink name=fpssink text-overlay=false video-sink="kmssink bus-id="a0070000.v_mix" show-preroll-frame=0"


This is a known issue with the Zynq UltraScale+ MPSoC VCU - LogiCORE H.264/H.265 Video Codec Unit (VCU).

Below are some methods to reduce initial "jerkiness":

  • Set the Zynq UltraScale+ MPSoC Encoder setting "qos=true"
  • Set the kmssink setting "show-preroll-frame=false" 

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
72293 PetaLinux 2019.1 - Product Update Release Notes and Known Issues N/A N/A
AR# 72328
Date 05/29/2019
Status Active
Type General Article
  • Zynq UltraScale+ MPSoC
  • GStreamer
  • VCU
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