From a1bf9472aec6932903163eb008dfcb57a892c7b3 Mon Sep 17 00:00:00 2001
From: Valmo Trindade <val_mo_jr@hotmail.com>
Date: Tue, 24 Jun 2025 19:34:08 -0300
Subject: [PATCH] added static video geoencoding to test KLV data

---
 src/video_stream.rs | 89 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 68 insertions(+), 21 deletions(-)

diff --git a/src/video_stream.rs b/src/video_stream.rs
index e4e34b3..0eac9b6 100644
--- a/src/video_stream.rs
+++ b/src/video_stream.rs
@@ -1,6 +1,7 @@
 use arma_rs::Context;
 use lazy_static::lazy_static;
-use std::process::Command;
+use std::io::Write;
+use std::process::{Command, Stdio};
 use std::sync::mpsc::{self, Receiver, Sender};
 use std::sync::Mutex;
 use std::thread;
@@ -27,6 +28,39 @@ fn build_rtsp_url(address: &str, port: &str, stream_path: &str, username: &str,
     }
 }
 
+fn generate_klv_packet() -> Vec<u8> {
+    fn encode_u16(value: f64, min: f64, max: f64) -> u16 {
+        let scale = (value - min) / (max - min);
+        (scale * u16::MAX as f64).round() as u16
+    }
+
+    fn encode_i64(value: f64, min: f64, max: f64) -> i64 {
+        let scale = (value - min) / (max - min);
+        (scale * i64::MAX as f64).round() as i64
+    }
+
+    let mut pkt = vec![];
+
+    // Heading (0x02)
+    pkt.extend([0x02, 0x02]);
+    pkt.extend(&encode_u16(182.0, 0.0, 360.0).to_be_bytes());
+
+    // Latitude (0x0D)
+    pkt.extend([0x0D, 0x08]);
+    pkt.extend(&encode_i64(-30.123456, -90.0, 90.0).to_be_bytes());
+
+    // Longitude (0x0E)
+    pkt.extend([0x0E, 0x08]);
+    pkt.extend(&encode_i64(-51.123456, -180.0, 180.0).to_be_bytes());
+
+    // Altitude (0x0F)
+    pkt.extend([0x0F, 0x04]);
+    let alt = ((430.0 / 19999.0) * u32::MAX as f64).round() as u32;
+    pkt.extend(&alt.to_be_bytes());
+
+    pkt
+}
+
 #[cfg(any(target_os = "windows", target_os = "linux"))]
 fn spawn_ffmpeg(
     rtsp_url: String,
@@ -35,28 +69,50 @@ fn spawn_ffmpeg(
 ) {
     thread::spawn(move || {
         let mut cmd = Command::new("ffmpeg");
+
         cmd.args(&[
-            "-f",
-            "gdigrab",
-            "-i",
-            "desktop",
-            "-f",
-            "rtsp",
-            "-rtsp_transport",
-            "tcp",
+            "-f", "gdigrab",
+            "-i", "desktop",
+            "-f", "klv",
+            "-i", "-",
+            "-map", "0:v",
+            "-map", "1",
+            "-c:v", "libx264",
+            "-metadata:s:1", "handler_name=klv_data",
+            "-f", "rtsp",
+            "-rtsp_transport", "tcp",
             &rtsp_url,
         ]);
 
         #[cfg(target_os = "windows")]
-        let child_result = cmd.creation_flags(CREATE_NO_WINDOW).spawn();
+        let child_result = cmd
+            .creation_flags(CREATE_NO_WINDOW)
+            .stdin(Stdio::piped())
+            .spawn();
 
         #[cfg(target_os = "linux")]
-        let child_result = cmd.spawn();
+        let child_result = cmd.stdin(Stdio::piped()).spawn();
 
         match child_result {
             Ok(mut child) => {
                 let _ = status_tx.send(Ok(()));
-                let _ = stop_rx.recv();
+
+                if let Some(mut stdin) = child.stdin.take() {
+                    let klv = generate_klv_packet();
+                    loop {
+                        if stop_rx.try_recv().is_ok() {
+                            break;
+                        }
+                        if stdin.write_all(&klv).is_err() {
+                            break;
+                        }
+                        if stdin.flush().is_err() {
+                            break;
+                        }
+                        thread::sleep(Duration::from_secs(1));
+                    }
+                }
+
                 let _ = child.kill();
             }
             Err(e) => {
@@ -74,8 +130,6 @@ pub fn start_stream(
     username: String,
     password: String,
 ) -> &'static str {
-    #[cfg(any(target_os = "windows", target_os = "linux"))]
-    {
         let (stop_tx, stop_rx) = mpsc::channel();
         let (status_tx, status_rx) = mpsc::channel();
 
@@ -109,13 +163,6 @@ pub fn start_stream(
                 "ffmpeg did not respond"
             }
         }
-    }
-
-    #[cfg(not(any(target_os = "windows", target_os = "linux")))]
-    {
-        ctx.callback_null("VIDEO ERROR", "Screen capture is only supported on Windows");
-        "unsupported platform"
-    }
 }
 
 pub fn stop_stream(ctx: Context) -> &'static str {