lesavka/client/src/output/video.rs

use gstreamer as gst;
use gstreamer_app as gst_app;
use gst::prelude::*;
use lesavka_common::lesavka::VideoPacket;
use winit::{
    event_loop::EventLoop,
    window::{Window, WindowAttributes},
};

pub struct MonitorWindow {
    id:     u32,
    _window: Window,
    src:    gst_app::AppSrc,
}

impl MonitorWindow {
    pub fn new(id: u32, el: &EventLoop<()>) -> anyhow::Result<Self> {
        gst::init()?;   // idempotent

        /*────────────────────── window ──────────────────────*/
        let window = el.create_window(
            WindowAttributes::default()
                .with_title(format!("Lesavka‑monitor‑{id}"))
                .with_decorations(false),
        )?;

        /*────────────────────── pipeline ────────────────────*/
        let caps = gst::Caps::builder("video/x-h264")
            .field("stream-format", &"byte-stream")
            .field("alignment",     &"au")
            .build();

        // Optional HW decode with VA‑API if LESAVKA_HW_DEC is set.
        let desc = if std::env::var_os("LESAVKA_HW_DEC").is_some() {
            concat!(
                "appsrc name=src is-live=true format=time do-timestamp=true block=false ! ",
                "capsfilter caps=video/x-h264,stream-format=byte-stream,alignment=au ! ",
                "queue max-size-buffers=0 max-size-bytes=0 max-size-time=0 leaky=downstream ! ",
                "h264parse ! vaapih264dec low-latency=true ! videoconvert ! ",
                "autovideosink sync=false",
            )
        } else {
            concat!(
                "appsrc name=src is-live=true format=time do-timestamp=true block=false ! ",
                "capsfilter caps=video/x-h264,stream-format=byte-stream,alignment=au ! ",
                "queue max-size-buffers=0 max-size-bytes=0 max-size-time=0 leaky=downstream ! ",
                "h264parse ! decodebin ! videoconvert ! autovideosink sync=false",
            )
        };

        let pipeline = gst::parse::launch(desc)?
            .downcast::<gst::Pipeline>()
            .expect("pipeline down‑cast");

        let src = pipeline
            .by_name("src")
            .expect("appsink")
            .downcast::<gst_app::AppSrc>()
            .expect("appsink down‑cast");

        src.set_caps(Some(&caps));
        src.set_format(gst::Format::Time);      // running‑time PTS
        src.set_property("blocksize", &0u32);   // whole AU per buffer
        src.set_latency(gst::ClockTime::NONE, gst::ClockTime::NONE);

        pipeline.set_state(gst::State::Playing)?;

        Ok(Self { id, _window: window, src })
    }

    /// Push one encoded access‑unit into the local pipeline.
    pub fn push_packet(&self, pkt: VideoPacket) {
        let mut buf = gst::Buffer::from_slice(pkt.data);
        if let Some(mut b) = buf.get_mut() {
            b.set_pts(Some(gst::ClockTime::from_useconds(pkt.pts)));
        }
        let _ = self.src.push_buffer(buf);      // ignore Eos / Flushing
    }
}