From 43d43084360ce557c1d8bb7a44279567219a49d9 Mon Sep 17 00:00:00 2001
From: Jonny Burger <jonathanburger11@gmail.com>
Date: Mon, 23 Feb 2026 09:39:01 +0100
Subject: [PATCH] Fix x265 SIGSEGV by patching FFmpeg x265 API guard

x265 build 210 changed x265_encoder_encode() to accept an array of
picture pointers, then build 213 reverted this. FFmpeg n7.1 only checks
`#if X265_BUILD >= 210`, so with our x265 build 215 it uses the wrong
calling convention, causing a SIGSEGV during h265 encoding.

Apply upstream FFmpeg fix (099f88b864) that narrows the guard to
`(X265_BUILD >= 210) && (X265_BUILD < 213)`.

Also adds x265 encoding test to CI to prevent regressions.

Closes https://github.com/remotion-dev/remotion/issues/6630

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 Dockerfile         |  1 +
 Dockerfile-aws     |  1 +
 compile-ffmpeg.mjs |  6 ++++++
 test-ffmpeg.mjs    | 22 ++++++++++++++++++++++
 x265-api.patch     | 31 +++++++++++++++++++++++++++++++
 5 files changed, 61 insertions(+)
 create mode 100644 x265-api.patch

diff --git a/Dockerfile b/Dockerfile
index 68790b4..f7f427c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,6 +13,7 @@ COPY sample.mp4 app/sample.mp4
 COPY sample-av1.webm app/sample-av1.webm
 COPY aac.patch app/aac.patch
 COPY hevc_ps.patch app/hevc_ps.patch
+COPY x265-api.patch app/x265-api.patch
 
 RUN apk add curl 
 RUN curl https://sh.rustup.rs -sSf | sh -s -- -y
diff --git a/Dockerfile-aws b/Dockerfile-aws
index 4364962..c7edec3 100644
--- a/Dockerfile-aws
+++ b/Dockerfile-aws
@@ -13,6 +13,7 @@ COPY sample.mp4 app/sample.mp4
 COPY sample-av1.webm app/sample-av1.webm
 COPY aac.patch app/aac.patch
 COPY hevc_ps.patch app/hevc_ps.patch
+COPY x265-api.patch app/x265-api.patch
 
 RUN curl https://sh.rustup.rs -sSf | sh -s -- -y
 RUN source "$HOME/.cargo/env"
diff --git a/compile-ffmpeg.mjs b/compile-ffmpeg.mjs
index 8e67daf..bd7de15 100644
--- a/compile-ffmpeg.mjs
+++ b/compile-ffmpeg.mjs
@@ -159,6 +159,9 @@ if (fs.existsSync("ffmpeg")) {
   execSync("git apply hevc_ps.patch --directory ffmpeg", {
     stdio: "inherit",
   });
+  execSync("git apply x265-api.patch --directory ffmpeg", {
+    stdio: "inherit",
+  });
 } else {
   execSync("git clone https://github.com/ffmpeg/ffmpeg.git", {
     stdio: "inherit",
@@ -173,6 +176,9 @@ if (fs.existsSync("ffmpeg")) {
   execSync("git apply hevc_ps.patch --directory ffmpeg", {
     stdio: "inherit",
   });
+  execSync("git apply x265-api.patch --directory ffmpeg", {
+    stdio: "inherit",
+  });
 }
 
 const extraCFlags = [
diff --git a/test-ffmpeg.mjs b/test-ffmpeg.mjs
index 3b3c5bf..507ab53 100644
--- a/test-ffmpeg.mjs
+++ b/test-ffmpeg.mjs
@@ -101,6 +101,28 @@ const exit5 = spawnSync(
 );
 assert(exit5.status === 0);
 
+const exit_x265 = spawnSync(
+  ffmpegBinary,
+  [
+    "-i",
+    "sample.mp4",
+    "-t",
+    "1",
+    "-c:v",
+    "libx265",
+    "out-test-x265.mp4",
+    "-y",
+  ],
+  {
+    env,
+    stdio: "inherit",
+  }
+);
+if (exit_x265.status !== 0) {
+  console.log("x265 encoding test failed with status", exit_x265.status, "signal", exit_x265.signal);
+}
+assert(exit_x265.status === 0);
+
 const exit6 = spawnSync(
   ffmpegBinary,
   [
diff --git a/x265-api.patch b/x265-api.patch
new file mode 100644
index 0000000..9de8484
--- /dev/null
+++ b/x265-api.patch
@@ -0,0 +1,31 @@
+diff --git a/libavcodec/libx265.c b/libavcodec/libx265.c
+index 38f0ab6b15..5d4fc43e92 100644
+--- a/libavcodec/libx265.c
++++ b/libavcodec/libx265.c
+@@ -661,7 +661,7 @@ static int libx265_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+ {
+     libx265Context *ctx = avctx->priv_data;
+     x265_picture x265pic;
+-#if X265_BUILD >= 210
++#if (X265_BUILD >= 210) && (X265_BUILD < 213)
+     x265_picture x265pic_layers_out[MAX_SCALABLE_LAYERS];
+     x265_picture* x265pic_lyrptr_out[MAX_SCALABLE_LAYERS];
+ #else
+@@ -805,7 +805,7 @@ static int libx265_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+ #endif
+     }
+
+-#if X265_BUILD >= 210
++#if (X265_BUILD >= 210) && (X265_BUILD < 213)
+     for (i = 0; i < MAX_SCALABLE_LAYERS; i++)
+         x265pic_lyrptr_out[i] = &x265pic_layers_out[i];
+
+@@ -844,7 +844,7 @@ static int libx265_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+             pkt->flags |= AV_PKT_FLAG_KEY;
+     }
+
+-#if X265_BUILD >= 210
++#if (X265_BUILD >= 210) && (X265_BUILD < 213)
+     x265pic_out = x265pic_lyrptr_out[0];
+ #else
+     x265pic_out = &x265pic_solo_out;