# VPU user guide

***Copyright © Quectel Wireless Solutions Co., Ltd. 2026. All rights reserved.***

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# 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:

```bash
# 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:

```bash
# 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):

```bash
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:

```bash
# 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)

```bash
# 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) |