pallete gen ffmpeg

server/src/services/discordBotService.js

@@ -272,6 +272,7 @@ async function buildReplayGif() {
       await fsp.writeFile(path.join(tmpDir, filename), frames[i].buffer);
     }
     const outPath = path.join(tmpDir, 'replay.gif');
+    const palettePath = path.join(tmpDir, 'palette.png');
     const delayMs = getRoomCameraReplayDelayMs();
     const fps = (1000 / delayMs).toFixed(3);
     await execFileAsync('ffmpeg', [
@@ -284,7 +285,22 @@ async function buildReplayGif() {
       '-i',
       'frame-%04d.jpg',
       '-vf',
-      'scale=640:-1:flags=lanczos',
+      'palettegen',
+      palettePath,
+    ], { cwd: tmpDir });
+    await execFileAsync('ffmpeg', [
+      '-y',
+      '-hide_banner',
+      '-loglevel',
+      'error',
+      '-framerate',
+      fps,
+      '-i',
+      'frame-%04d.jpg',
+      '-i',
+      'palette.png',
+      '-lavfi',
+      'paletteuse=dither=bayer:bayer_scale=5',
       '-loop',
       '0',
       outPath,