Hardware‑accelerated 2D colour‑space conversion and scaling for Rockchip SoCs (RK3588/RK356x/…) powered by RGA.
RGA is Rockchip’s on‑chip 2D engine that performs BLIT, resize, rotation and pixel‑format transforms with very low CPU overhead.
Status: experimental but production-tested for 6 x 1080p30 pipelines on RK3588. RGA3 core0 and core1 are 88 % occupied.
- Colours‑space conversion between NV12/NV21/I420/YV12/… and RGB/BGR/BGRA/RGBA.
- Image resizing up to 8192x8192 input, 4096x4096 output (RGA H/W limit).
- Multistream aware – tested with 6 parallel operations on RK3588.
- Runtime core selection ‑ new
core-maskproperty lets you pin jobs to RGA3 or RGA2 cores. - Zero‑copy DMA‑BUF support when upstream allocators provide dmabuf FDs.
| component | minimum version | note |
|---|---|---|
| GStreamer | 1.16 | |
| librga | v2.2.0 + | |
| Meson ‑ Ninja | ≥ 1.3.2/1.11.1 | build system |
| Rockchip kernel | ≥ 5.10 | enables IOMMU for RGA3 and provides RGA multi-core driver |
# 1. Clone
$ git clone https://github.com/corenel/gstreamer-rga.git
$ cd gstreamer-rga
# 2. Configure (default = /usr/local)
$ meson setup build
# or install to HOME so you don’t need root:
$ meson setup --prefix "$HOME/.local" build
# 3. Compile
$ ninja -C build
# 4. Install (drop sudo if installing to HOME)
$ sudo ninja -C build install
# 5. Tell GStreamer where to find the plugin (if installing to HOME)
$ export GST_PLUGIN_PATH_1_0="$HOME/.local/lib/$(uname -m)-linux-gnu/gstreamer-1.0"
# 6. Clear GStreamer cache
$ rm -rf ~/.cache/gstreamer-1.0/*
# 7. Check installation
$ gst-inspect-1.0 rgavideoconvert
Factory Details:
Rank primary (256)
Long-name RgaVidConv Plugin
Klass Generic
Description Converts video from one colorspace to another & Resizes via Rockchip RGA
Author http://github.com/corenel/gstreamer-rga
Plugin Details:
Name rgavideoconvert
Description video Colorspace conversion & scaler
Filename /usr/lib/aarch64-linux-gnu/gstreamer-1.0/libgstrgavideoconvert.so
Version 0.1.0
License MIT/X11
Source module gst-rga
Binary package gstreamer-rga
Origin URL https://github.com/corenel/gstreamer-rga.git
GObject
+----GInitiallyUnowned
+----GstObject
+----GstElement
+----GstBaseTransform
+----GstVideoFilter
+----GstRgaVideoConvert
Pad Templates:
SINK template: 'sink'
Availability: Always
Capabilities:
video/x-raw
format: { (string)I420, (string)YV12, (string)NV12, (string)NV21, (string)Y42B, (string)NV16, (string)NV61, (string)RGB16, (string)RGB15, (string)BGR, (string)RGB, (string)BGRA, (string)RGBA, (string)BGRx, (string)RGBx }
width: [ 1, 8192 ]
height: [ 1, 8192 ]
framerate: [ 0/1, 2147483647/1 ]
SRC template: 'src'
Availability: Always
Capabilities:
video/x-raw
format: { (string)I420, (string)YV12, (string)NV12, (string)NV21, (string)Y42B, (string)NV16, (string)NV61, (string)RGB16, (string)RGB15, (string)BGR, (string)RGB, (string)BGRA, (string)RGBA, (string)BGRx, (string)RGBx }
width: [ 1, 4096 ]
height: [ 1, 4096 ]
framerate: [ 0/1, 2147483647/1 ]
Element has no clocking capabilities.
Element has no URI handling capabilities.
Pads:
SINK: 'sink'
Pad Template: 'sink'
Pad Template: 'sink'
SRC: 'src'
Pad Template: 'src'
Element Properties:
core-mask : Select which RGA core(s) to use (bit-mask)
flags: readable, writable
Flags "GstRgaCoreMask" Default: 0x00000000, "(none)"
(0x00000001): auto - auto
(0x00000001): rga3_core0 - rga3_core0
(0x00000002): rga3_core1 - rga3_core1
(0x00000004): rga2_core0 - rga2_core0
(0x00000003): rga3 - rga3
(0x00000004): rga2 - rga2
name : The name of the object
flags: readable, writable
String. Default: "rgavideoconvert0"
parent : The parent of the object
flags: readable, writable
Object of type "GstObject"
qos : Handle Quality-of-Service events
flags: readable, writable
Boolean. Default: true# NV12 1080p -> BGR 640×480 with automatic core scheduling
gst-launch-1.0 videotestsrc ! video/x-raw,width=1920,height=1080,format=NV12 \
! rgavideoconvert ! video/x-raw,width=640,height=480,format=BGR ! fakesink
# Pin work to RGA3 only – avoids 32-bit limitation of RGA2
gst-launch-1.0 filesrc location=test.h264 ! h264parse ! mppvideodec \
! rgavideoconvert core-mask=rga3 \
! video/x-raw,width=1280,height=720,format=BGRx ! fakesinkThe property is a GFlags bit‑mask.
| string value | bits | meaning |
|---|---|---|
auto (default) |
0 | let librga scheduler decide |
rga3 |
IM_SCHEDULER_RGA3_CORE0 | IM_SCHEDULER_RGA3_CORE1 |
dual‑core 64‑bit |
rga2 |
IM_SCHEDULER_RGA2_CORE0 |
legacy 32‑bit core |
rga3_core0 |
single core | |
rga3_core1 |
single core | |
rga2_core0 |
single core |
Set it per element: … ! rgavideoconvert core-mask=rga3 ! …
# Prepare test file
gst-launch-1.0 videotestsrc num-buffers=3000 ! video/x-raw,width=1920,height=1080,format=NV12 ! mpph264enc ! h264parse ! filesink location=test.h264
# Run 6 parallel streams (w/ gst-shark for CPU usage monitoring)
GST_DEBUG="GST_TRACER:7" \
GST_TRACERS="cpuusage" \
gst-launch-1.0 -e filesrc location=test.h264 ! h264parse ! tee name=t \
$(for i in $(seq 1 6); do echo "t. ! queue ! mppvideodec ! rgavideoconvert core-mask=rga3 \
! video/x-raw,width=640,height=480,format=BGR ! queue ! fakesink sync=false "; done)
# Monitor RGA usage (on a separate terminal)
watch -n 0.5 cat /sys/kernel/debug/rkrga/load- Prefer RGA3 on boards with > 4 GB RAM – RGA2 can only DMA below 4 GB.
- Map upstream buffers with DMA32/IOMMU flags when you really need RGA2.
- Always insert
queuebetween decoder andrgavideoconvertfor smooth parallelism.
| symptom | cause | remedy |
|---|---|---|
swiotlb buffer is full + Failed to map attachment |
buffers above 4 GB scheduled on RGA2 | set core-mask=rga3 or force DMA32 allocations |
not negotiated errors |
caps mismatch | verify width/height within limits (in≤8192, out≤4096) |
No such element rgavideoconvert |
plugin not found | ensure GST_PLUGIN_PATH_1_0 includes install dir |
- airockchip/librga – original RGA library
- higithubhi/gstreamer-rgaconvert – original GStreamer plugin
MIT – see LICENSE.