RDI-3231 Add RDP 4:4:4 GStreamer Elements for AVC444v2 Encoding/Decoding

meson_options.txt

@@ -1,6 +1,6 @@
 option('ttml', type : 'feature', value : 'auto', description : 'Build GStreamer Fluendo TTML Element')
 option('injectbin', type : 'feature', value : 'auto', description : 'Build GStreamer Fluendo injectbin Element')
-
+option('rdp444', type : 'feature', value : 'auto', description : 'Build GStreamer Fluendo RDP YUV444 encoding plugin')
 # gst-fluendo-ttml options
 option('ttml_build_ttmlparse', type : 'feature', value : 'enabled', description : 'gst-fluendo-ttml: build the ttmlparse element')
 option('ttml_build_ttmlrender', type : 'feature', value : 'enabled', description : 'gst-fluendo-ttml: build the ttmlrender element')

plugins/meson.build

@@ -8,6 +8,7 @@ plugins = {
 # Plugin Name             Supported OS                            Description
   'ttml':                 { 'os': ['linux', 'windows', 'darwin'],    'desc': 'GStreamer Fluendo TTML Element' },
   'injectbin':            { 'os': ['linux', 'windows', 'darwin'],    'desc': 'GStreamer Fluendo dynamic pipeline rebuild element' },
+  'rdp444':               { 'os': ['linux', 'windows', 'darwin'],    'desc': 'GStreamer Fluendo RDP YUV444 element' },
 }
 
 # Meson builds OSX libraries with '.dylib' extension. However, the name_suffix

plugins/rdp444/README.md

@@ -0,0 +1,165 @@
+# RDP 4:4:4 GStreamer Elements (AI Generated)
+
+## Overview
+
+This plugin provides two complementary GStreamer elements that implement the Microsoft RDP AVC444v2 encoding scheme for splitting and combining 4:4:4 chroma video streams. This encoding is used in Remote Desktop Protocol (RDP) to efficiently transmit full chroma video over two separate 4:2:0 video streams.
+
+### Elements
+
+- **rdp444split** - Splits Y444 (4:4:4) video into two I420 (4:2:0) streams
+- **rdp444combine** - Combines two I420 (4:2:0) streams back into Y444 (4:4:4) video
+
+## rdp444split
+
+### Description
+
+The `rdp444split` element takes a single Y444 input stream and splits it into two I420 outputs according to the Microsoft RDP AVC444v2 specification. The element distributes the chroma information across two 4:2:0 streams in a way that allows perfect reconstruction.
+
+### Pads
+
+- **Sink pad**: `sink`
+  - Caps: `video/x-raw, format=Y444`
+
+- **Source pads**:
+  - `src_yuv420` - Main view containing full luma and even-pixel chroma
+  - `src_chroma420` - Auxiliary view containing odd-pixel chroma information
+  - Caps: `video/x-raw, format=I420`
+
+### Encoding Scheme
+
+The element implements the Microsoft RDP AVC444v2 encoding specification:
+
+**Main View (src_yuv420):**
+- B1: Y₄₂₀(x,y) = Y₄₄₄(x,y) - Full luma plane
+- B2: U₄₂₀(x,y) = U₄₄₄(2x, 2y) - Even pixel U samples
+- B3: V₄₂₀(x,y) = V₄₄₄(2x, 2y) - Even pixel V samples
+
+**Auxiliary View (src_chroma420):**
+- B4: Y₄₂₀(x,y) = U₄₄₄(2x+1, y) - U odd columns (left half)
+- B5: Y₄₂₀(W/2+x,y) = V₄₄₄(2x+1, y) - V odd columns (right half)
+- B6: U₄₂₀(x,y) = U₄₄₄(4x, 2y+1) - U odd rows (left quarter)
+- B7: U₄₂₀(W/4+x,y) = V₄₄₄(4x, 2y+1) - V odd rows (right quarter)
+- B8: V₄₂₀(x,y) = U₄₄₄(4x+2, 2y+1) - U odd rows offset (left quarter)
+- B9: V₄₂₀(W/4+x,y) = V₄₄₄(4x+2, 2y+1) - V odd rows offset (right quarter)
+
+### Properties
+
+None
+
+## rdp444combine
+
+### Description
+
+The `rdp444combine` element performs the inverse operation of `rdp444split`. It takes two I420 input streams and reconstructs the original Y444 output by reversing the AVC444v2 encoding scheme.
+
+### Pads
+
+- **Sink pads**:
+  - `sink_yuv420` - Main view (full luma + even chroma)
+  - `sink_chroma420` - Auxiliary view (odd chroma samples)
+  - Caps: `video/x-raw, format=I420`
+
+- **Source pad**: `src`
+  - Caps: `video/x-raw, format=Y444`
+
+### Decoding Scheme
+
+The element reconstructs Y444 by reversing the encoding:
+
+- Y₄₄₄(x,y) = Y₄₂₀_main(x,y) - From B1: Full luma
+- U₄₄₄(2x, 2y) = U₄₂₀_main(x,y) - From B2: Even pixel U
+- V₄₄₄(2x, 2y) = V₄₂₀_main(x,y) - From B3: Even pixel V
+- U₄₄₄(2x+1, y) = Y₄₂₀_aux(x,y) - From B4: U odd columns
+- V₄₄₄(2x+1, y) = Y₄₂₀_aux(W/2+x,y) - From B5: V odd columns
+- U₄₄₄(4x, 2y+1) = U₄₂₀_aux(x,y) - From B6: U odd rows
+- V₄₄₄(4x, 2y+1) = U₄₂₀_aux(W/4+x,y) - From B7: V odd rows
+- U₄₄₄(4x+2, 2y+1) = V₄₂₀_aux(x,y) - From B8: U odd rows offset
+- V₄₄₄(4x+2, 2y+1) = V₄₂₀_aux(W/4+x,y) - From B9: V odd rows offset
+
+### Properties
+
+None
+
+## Example Pipelines
+
+### Round-trip Test
+
+Complete pipeline that splits and recombines Y444 video:
+
+```bash
+gst-launch-1.0 -v videotestsrc ! \
+  "video/x-raw,format=Y444,width=640,height=480,framerate=30/1" ! \
+  rdp444split name=split \
+  split.src_yuv420 ! queue ! combine.sink_yuv420 \
+  split.src_chroma420 ! queue ! combine.sink_chroma420 \
+  rdp444combine name=combine ! \
+  "video/x-raw,format=Y444,width=640,height=480" ! \
+  videoconvert ! autovideosink
+```
+
+This pipeline demonstrates:
+1. Generating Y444 test pattern (640x480)
+2. Splitting into two I420 streams (main + auxiliary)
+3. Routing through queues for synchronization
+4. Recombining back to Y444
+5. Displaying the reconstructed video
+
+### Viewing Split Output
+
+To visualize the split streams (note: auxiliary view will appear corrupted as shown in the example image):
+
+```bash
+# View main stream
+gst-launch-1.0 videotestsrc ! \
+  "video/x-raw,format=Y444,width=640,height=480" ! \
+  rdp444split name=split \
+  split.src_yuv420 ! videoconvert ! autovideosink
+
+# View auxiliary stream (chroma data packed into I420)
+gst-launch-1.0 videotestsrc ! \
+  "video/x-raw,format=Y444,width=640,height=480" ! \
+  rdp444split name=split \
+  split.src_chroma420 ! videoconvert ! autovideosink
+```
+
+**Note**: When viewing the auxiliary stream directly, the output will appear corrupted/fragmented because it contains packed chroma samples that are not meant to be displayed as a normal image. This is expected behavior - the auxiliary stream only makes sense when recombined with the main stream.
+
+## Technical Details
+
+### Implementation
+
+Both elements are implemented as GStreamer bin elements:
+- `rdp444split` extends `GstElement` with custom pad management
+- `rdp444combine` extends `GstAggregator` for synchronized input handling
+
+### Performance Considerations
+
+- The split operation uses `memcpy()` for luma plane copying (efficient)
+- Chroma resampling involves per-pixel operations
+- Combine operation reconstructs full chroma resolution
+- Both elements preserve timestamps and metadata
+
+### Use Cases
+
+1. **Remote Desktop Protocol**: Transmit 4:4:4 video over RDP using two H.264 streams
+2. **High-quality video transmission**: Leverage existing 4:2:0 encoders for 4:4:4 content
+3. **Video conferencing**: Maintain full chroma resolution in bandwidth-constrained scenarios
+4. **Testing**: Verify codec implementations and video processing pipelines
+
+## Building
+
+The plugin is built as part of the flu-plugins-oss project:
+
+```bash
+meson setup builddir
+ninja -C builddir
+```
+
+## References
+
+- [MS-RDPEGFX]: Remote Desktop Protocol: Graphics Pipeline Extension
+## License
+
+Copyright (C) 2026 Fluendo <engineering@fluendo.com>
+
+See LICENSE file for details.