Merge pull request #1675 from CapSoftware/cursor/cap-export-speed-ad7f

perf: improve export speed with pipeline restructure, cursor precomputation, and encoder tuning

Author: richiemcilroy

apps/desktop/src-tauri/src/editor_window.rs

@@ -37,7 +37,7 @@ async fn do_prewarm(app: AppHandle, path: PathBuf) -> PendingResult {
                         GpuOutputFormat::Rgba => WSFrameFormat::Rgba,
                     };
                     WSFrame {
-                        data: frame.data,
+                        data: Arc::new(frame.data.into_vec()),
                         width: frame.width,
                         height: frame.height,
                         stride: frame.y_stride,
@@ -254,7 +254,7 @@ impl EditorInstances {
                                     GpuOutputFormat::Rgba => WSFrameFormat::Rgba,
                                 };
                                 WSFrame {
-                                    data: frame.data,
+                                    data: Arc::new(frame.data.into_vec()),
                                     width: frame.width,
                                     height: frame.height,
                                     stride: frame.y_stride,

crates/enc-ffmpeg/src/video/h264.rs

@@ -776,6 +776,18 @@ fn get_codec_and_options(
                             _ => "veryfast",
                         },
                     );
+                    if !matches!(preset, H264Preset::Slow | H264Preset::Medium) {
+                        let thread_count = thread::available_parallelism()
+                            .map(|v| v.get())
+                            .unwrap_or(4);
+                        options.set("threads", &thread_count.to_string());
+                        options.set("rc-lookahead", "10");
+                        options.set("b-adapt", "1");
+                        options.set("aq-mode", "1");
+                        options.set("ref", "2");
+                        options.set("subme", "2");
+                        options.set("trellis", "0");
+                    }
                 } else {
                     options.set(
                         "preset",