From 69062205fd9c6d403b6e368ddf7ebfe0e0908e78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastjan=20Arti=C4=8D?= <sebastjan@folx.tv>
Date: Thu, 30 Apr 2026 12:01:06 +0000
Subject: [PATCH] Fix preview-clip ffmpeg: force even dimensions for libx264

Bug: 'width not divisible by 2 (853x480)' from screenshot.
libx264 requires even width/height. scale=854:480 + decrease can result
in 853x480 (odd width).

Fix: chain second scale filter that truncates to nearest even number:
  scale=trunc(iw/2)*2:trunc(ih/2)*2

Verified locally: 4.4MB clip in 4.8s on CPU.
---
 app/main.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/main.py b/app/main.py
index 34278f1..88ac19b 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1291,7 +1291,7 @@ async def preview_clip(
             "-i", str(src),
             "-ss", f"{min(0.5, start):.2f}",  # fine seek
             "-t", f"{duration:.2f}",
-            "-vf", "scale=854:480:force_original_aspect_ratio=decrease",  # 480p
+            "-vf", "scale=854:480:force_original_aspect_ratio=decrease,scale=trunc(iw/2)*2:trunc(ih/2)*2",  # 480p, even dimensions for libx264
             "-c:v", "libx264",
             "-preset", "ultrafast",  # NAJHITREJŠI preset
             "-crf", "30",  # nižja kvaliteta = hitrejše