Module gstreamer_pipe

Expand description

Real video decode via the gst-launch-1.0 and gst-discoverer-1.0 CLIs.

Mirrors the spirit of crate::mock::MockVideoStream but reads bytes from a real GStreamer pipeline:

filesrc location=<path>
  ! decodebin
  ! videoconvert
  ! video/x-raw,format=BGRA
  ! fdsink fd=1

§Trade-offs

+ Zero compile-time integration with libgstreamer; works against any system GStreamer the user installs (brew install gstreamer, apt install gstreamer1.0-tools, …). No FFI surface.
+ GStreamer is LGPL — friendlier than FFmpeg’s GPL-or-LGPL split, no licensing entanglement for our binary either way.
+ Hardware decode picks up automatically when GStreamer’s vah264dec / vtdec / nvh264dec plugins are present.
− Per-process fork; for the player loop that’s one fork for the whole stream, not per-frame.
− Assumes gst-launch-1.0 and gst-discoverer-1.0 on PATH. Reported as Error::Spawn rather than a panic.

For a proper Rust-bound integration via gstreamer-rs see M-DEC.3+; the crate::VideoStream trait makes it a swap-in replacement.

GstreamerPipeStream: Streams BGRA frames from a video file by piping it through gst-launch-1.0.
VideoMetadata: Per-stream metadata, as reported by gst-discoverer-1.0.

file_uri 🔒
gstreamer_available: Whether both gst-launch-1.0 and gst-discoverer-1.0 are on PATH and runnable. Useful as a runtime guard for tests + production code that wants to gracefully degrade when GStreamer isn’t installed.
parse_clock 🔒: Parses gst-discoverer-1.0 Duration: clocks like 0:00:00.266666666.
parse_discoverer 🔒: Parse gst-discoverer-1.0 -v output for the first video stream.
parse_rational 🔒: Parses gst-discoverer-1.0 rationals like 30/1 or 30000/1001.