VPU user guide¶

What is VPU¶

VPU (Video Processing Unit) is the dedicated video encode/decode hardware integrated in the RK3576. It works independently of the CPU and is responsible for encoding and decoding H.264, H.265, AV1, VP9, JPEG and other video/image formats.

What happens without a VPU? When playing HD video, the CPU must decode in software at full load, which easily causes lag, heat, and high power consumption. With a VPU, decoding is done entirely in hardware, leaving the CPU free for other tasks — even 4K video plays smoothly.

VPU Use Cases¶

Scenario	Description	Operation
Video playback	Hardware decode H.264/H.265/AV1/VP9 video	GStreamer playback
Video recording	Hardware encode camera frames to H.264 file	GStreamer encoding
Video transcoding	Convert one format to another	Decode + encode in series
Video streaming	Real-time encode and network transmission	Encode + UDP output

Using the VPU on M2¶

Scenario 1: Hardware Decode Video Playback (Most Common)¶

Play the onboard test video with hardware decode:

# Play the onboard 720p test video (hardware decode)
gst-launch-1.0 filesrc location=/oem/SampleVideo_1280x720_5mb.mp4 ! \
  qtdemux ! h264parse ! mppvideodec ! waylandsink

Element	Function
filesrc	Read video file
qtdemux	Demux (extract H.264 stream)
h264parse	Parse H.264 bitstream
mppvideodec	VPU hardware decode (key)
waylandsink	Display to screen (GPU rendering)

Smooth playback with low CPU usage (observe with top; the decode process CPU usage should be very low) indicates the VPU is working.

Scenario 2: Hardware Encoding (Record Video)¶

Hardware encode test frames to an H.264 file:

# Generate 30 frames of test video and hardware encode to H.264
gst-launch-1.0 videotestsrc num-buffers=30 ! videoconvert ! \
  video/x-raw,format=NV12,width=640,height=480 ! \
  mpph264enc ! filesink location=/tmp/test.h264

# View the generated file
ls -la /tmp/test.h264

You can also re-encode hardware-decoded video (transcoding):

gst-launch-1.0 -e filesrc location=/oem/SampleVideo_1280x720_5mb.mp4 ! \
  qtdemux ! h264parse ! mppvideodec ! videoconvert ! \
  video/x-raw,format=NV12 ! mpph264enc ! filesink location=/tmp/out.h264

Scenario 3: Decode Performance Test (Verify VPU Speed)¶

Use the MPP decode test tool to see how many frames per second the VPU can decode:

# Decode 200 frames of 720p H.264 raw stream
mpi_dec_test -i /oem/200frames_count.h264 -t 7 -w 1280 -h 720 -n 200 -v f

M2 measured results:

Resolution	Format	Instances	Frame Rate	Real-time Multiplier
1280x720	H.264	1	3003 fps	100x
1920x1080	H.264	1	2962 fps	124x
1280x720	H.264	4 concurrent	2907 fps/stream	97x/stream
1280x720	H.264	8 concurrent	2840 fps/stream	95x/stream

8-stream 720p concurrent decoding with no pressure — suitable for NVR / multi-channel surveillance scenarios.

VPU Supported Formats¶

Type	Format	GStreamer Plugin
Decode	H.264 / H.265 / AV1 / VP8 / VP9 / MPEG4	mppvideodec
Decode	JPEG	mppjpegdec
Encode	H.264	mpph264enc
Encode	H.265	mpph265enc
Encode	JPEG	mppjpegenc

Environment Check (One-Step VPU Readiness)¶

# VPU device node exists
ls /dev/mpp_service

# GStreamer hardware plugins exist
gst-inspect-1.0 | grep -i rockchipmpp
# Expected: mpph264enc / mpph265enc / mppjpegdec / mppjpegenc / mppvideodec

FAQ¶

Problem	Solution
Black screen / no video	Run in a graphical desktop session; waylandsink requires a Wayland environment
mppvideodec not found	Install gstreamer1.0-rockchip1 (preinstalled on both platforms)
Encode reports invalid format	Input pixel format must be NV12 (add video/x-raw,format=NV12)
Decode shows artifacts	Input must be H.264 raw stream or mp4 container (demux with qtdemux first)