From b1efd289d3f04bd01b8aa503aba2055648add04d Mon Sep 17 00:00:00 2001
From: Manav Rathi <manav@mnvr.in>
Date: Tue, 29 Apr 2025 13:04:15 +0530
Subject: [PATCH] tm thumb

---
 web/packages/gallery/services/ffmpeg/index.ts | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/web/packages/gallery/services/ffmpeg/index.ts b/web/packages/gallery/services/ffmpeg/index.ts
index 2c408c3c66..d0309b22a6 100644
--- a/web/packages/gallery/services/ffmpeg/index.ts
+++ b/web/packages/gallery/services/ffmpeg/index.ts
@@ -83,12 +83,23 @@ const makeGenThumbnailCommand = (seekTime: number) => [
     ffmpegPathPlaceholder,
     "-i",
     inputPathPlaceholder,
+    // Seek to seekTime in the video.
     "-ss",
     `00:00:0${seekTime}`,
+    // Take the first frame
     "-vframes",
     "1",
+    // Apply a filter to this frame
     "-vf",
-    "scale=-1:720",
+    [
+        // - Scale it to a maximum height of 720 keeping aspect ratio
+        "scale=-1:720",
+        // - Apply a tonemap to ensure that thumbnails of HDR videos do not look
+        //   washed out. See: [Note: Tonemapping HDR to HD].
+        "zscale=transfer=linear",
+        "tonemap=tonemap=hable:desat=0",
+        "zscale=primaries=709:transfer=709:matrix=709",
+    ].join(","),
     outputPathPlaceholder,
 ];