Hi,
I am currently writing a plugin in Rust that receives (video) metadata and writes it to file. I’ve based it on gst_base::BaseSink and implemented the functions start(), stop() and render(). The intention is to collect the metadata (VideoRegionOfInterest) and write it to file once the pipeline reaches eos and calls stop(). I am able to run the plugin in the pipeline and can verify that the functions above are called. However, I don’t seem to be able to retrieve the metdata from the gst::Buffer even though it has been added in previous plugins. If I use a video filter plugin, the metadata is available. Here are the snippets:
When using the sink plugin, no metadata available:
fn render(&self, buffer: &gst::Buffer) -> Result<gst::FlowSuccess, gst::FlowError> {
event!(Level::INFO, "Render");
let mut state = self.state.lock().unwrap();
match *state {
State::Stopped => {
event!(Level::ERROR, "State was not started");
return Err(gst::FlowError::Error);
},
State::Started(ref mut value) => {
let roi_metas = buffer.iter_meta::<VideoRegionOfInterestMeta>();
event!(Level::INFO, "Meta count {}", roi_metas.count()); //<- always 0
...
}
when using this Video Filter plugin, the metadata is available
/// Implementation of gst::VideoFilter virtual methods
impl VideoFilterImpl for AdvPrint {
fn transform_frame_ip(
&self,
frame: &mut gst_video::VideoFrameRef<&mut gst::BufferRef>,
) -> Result<gst::FlowSuccess, gst::FlowError> {
let width = frame.width() as usize;
let height = frame.height() as usize;
let stride = frame.plane_stride()[0];
println!(
"ADVPRINT width: {}, height: {} stride: {}",
width, height, stride
);
let roi_metas = frame.buffer().iter_meta::<VideoRegionOfInterestMeta>(); // metadata available
What could be the issue? Is there a better approach to accomplish what I am trying to do? Thanks for any input.
PS: I cannot provide an running example at the moment.