invert scroll zoom direction

closes #2703

src/main/ffmpeg.ts

@@ -141,7 +141,10 @@ function runFfmpegProcess(args: readonly string[], customExecaOptions?: ExecaOpt
 }
 
 export async function runFfmpegConcat({ ffmpegArgs, concatTxt, totalDuration, onProgress }: {
-  ffmpegArgs: string[], concatTxt: string, totalDuration: number, onProgress: (a: number) => void
+  ffmpegArgs: string[],
+  concatTxt: string,
+  totalDuration: number,
+  onProgress: (a: number) => void,
 }) {
   const process = runFfmpegProcess(ffmpegArgs);
 

src/renderer/src/hooks/useTimelineScroll.ts

@@ -42,7 +42,8 @@ function useTimelineScroll({ wheelSensitivity, mouseWheelZoomModifierKey, mouseW
     const makeUnit = (v: number) => ((direction * v) > 0 ? 1 : -1);
 
     if (wheelEvent[keyMap[mouseWheelZoomModifierKey]]) {
-      zoomRel(direction * pixelY * wheelSensitivity * 0.4);
+      // negative because https://github.com/mifi/lossless-cut/issues/2703
+      zoomRel(-direction * pixelY * wheelSensitivity * 0.4);
     } else if (wheelEvent[keyMap[mouseWheelFrameSeekModifierKey]]) {
       shortStep(makeUnit(pixelX + pixelY));
     } else if (wheelEvent[keyMap[mouseWheelKeyframeSeekModifierKey]]) {