GStreamer videotestsrc through Wisp
Real GStreamer frames through the same VideoTexture path that
M-MEDIA.12 stood up with synthetic frames. Closes the loop: the
recorder's video intake (M-MEDIA.6) feeds wisp's rendering pipeline
(M-MEDIA.12) end-to-end.
Frame 0 of videotestsrc's default SMPTE-colorbars pattern at
320×180, captured via the M-MEDIA.6 CLI-pipe wrapper, uploaded to a
wisp VideoTexture, and rendered through Sprite.
Run
cargo run -p media --example gst_video_to_wisp
Eight frames at 30 fps are captured and rendered. Output lands under
target/gst-video-frames/frame_NN.png with a per-frame PTS log:
frame 00: pts = 0.000 s ( 0 ns), index = 0
frame 01: pts = 0.033 s ( 33333333 ns), index = 1
frame 02: pts = 0.067 s ( 66666667 ns), index = 2
…
frame 07: pts = 0.233 s ( 233333333 ns), index = 7
Summary: 8 frames captured, 8 VideoTexture uploads,
8 cumulative gst frames emitted.
The wiring
sequenceDiagram
participant Gst as gst-launch-1.0 videotestsrc
participant Cap as GstreamerVideoCapture
participant Tex as wisp::VideoTexture
participant Ren as wisp::Renderer
participant Out as PNG
loop frame i ∈ [0, 8)
Gst->>Cap: BGRA frame via fdsink
Cap->>Tex: upload_bgra(app, frame.bgra)
Tex->>Ren: Stage with Sprite(tex)
Ren->>Out: render_target.read_pixels → PNG
end
The media library never imports wisp or wgpu. The example
brings them in as dev-dependencies so cargo run -p media --example gst_video_to_wisp works, but cargo doc -p media and
downstream consumers of the library don't pull wgpu into their tree.
The boundary stays clean.
Manual regression
After running, verify:
| Field | Expected |
|---|---|
| PTS cadence | 33_333_333 ns between frames (30 fps) |
| frame_index | monotonic 0..8 |
| png count | 8 files under target/gst-video-frames/ |
| frame 0 content | SMPTE colorbars (white, yellow, cyan, green, magenta, red, blue stripes + noise band on top) |
Real-webcam capture (M-MEDIA.16) drops in here without any of the wisp-side code changing. The video texture is format-agnostic at the contract level — caps to BGRA on the GStreamer side, upload, render.
Next
Synced video + audio histogram in one Wisp scene — combines this video render with the M-MEDIA.10 audio histogram so the two shows the recorder's two intake streams composed against one timeline.