From 8a796c76c81f8bffd0b7ce94342d771d5f5cc4e4 Mon Sep 17 00:00:00 2001
From: Christoph Reiter <reiter.christoph@gmail.com>
Date: Fri, 17 Nov 2023 15:07:12 +0100
Subject: [PATCH] ffmpeg: add patch to workaround vlc crash with dxva2 hwaccel

---
 .../0015-guard-null-hw-frames-ctx.patch       | 69 +++++++++++++++++++
 mingw-w64-ffmpeg/PKGBUILD                     |  9 ++-
 2 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 mingw-w64-ffmpeg/0015-guard-null-hw-frames-ctx.patch

diff --git a/mingw-w64-ffmpeg/0015-guard-null-hw-frames-ctx.patch b/mingw-w64-ffmpeg/0015-guard-null-hw-frames-ctx.patch
new file mode 100644
index 0000000000..57545acdeb
--- /dev/null
+++ b/mingw-w64-ffmpeg/0015-guard-null-hw-frames-ctx.patch
@@ -0,0 +1,69 @@
+Guard against segfault running VLC decoding under msys2 [1]:
+
+Thread 33 received signal SIGSEGV, Segmentation fault.
+[Switching to Thread 37728.0xadd0]
+ff_hwaccel_frame_priv_alloc (avctx=0x6447b00, hwaccel_picture_private=0x65dfd00)
+    at libavcodec/decode.c:1848
+1848        frames_ctx = (AVHWFramesContext *)avctx->hw_frames_ctx->data;
+(gdb) bt
+    at libavcodec/decode.c:1848
+    at libavcodec/h264_slice.c:208
+    first_slice=1) at libavcodec/h264_slice.c:1599
+    at libavcodec/h264_slice.c:2130
+    at libavcodec/h264dec.c:652
+    got_frame=0x646e4b0, avpkt=0x64522c0) at libavcodec/h264dec.c:1048
+
+(gdb) p avctx
+$1 = (AVCodecContext *) 0x6447b00
+(gdb) p avctx->hw_frames_ctx
+$2 = (AVBufferRef *) 0x0
+
+v2: check for free_frame_priv (Hendrik)
+v3: return EINVAL (Christoph Reiter)
+
+See[1]: https://github.com/msys2/MINGW-packages/pull/19050
+Fixes: be07145109 ("avcodec: add AVHWAccel.free_frame_priv callback")
+CC: Lynne <dev at lynne.ee>
+CC: Christoph Reiter <reiter.christoph at gmail.com>
+Signed-off-by: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
+---
+ libavcodec/decode.c | 18 +++++++++++++-----
+ 1 file changed, 13 insertions(+), 5 deletions(-)
+
+diff --git a/libavcodec/decode.c b/libavcodec/decode.c
+index ad39021..50c3995 100644
+--- a/libavcodec/decode.c
++++ b/libavcodec/decode.c
+@@ -1838,17 +1838,25 @@ int ff_copy_palette(void *dst, const AVPacket *src, void *logctx)
+ int ff_hwaccel_frame_priv_alloc(AVCodecContext *avctx, void **hwaccel_picture_private)
+ {
+     const FFHWAccel *hwaccel = ffhwaccel(avctx->hwaccel);
+-    AVHWFramesContext *frames_ctx;
+ 
+     if (!hwaccel || !hwaccel->frame_priv_data_size)
+         return 0;
+ 
+     av_assert0(!*hwaccel_picture_private);
+ 
+-    frames_ctx = (AVHWFramesContext *)avctx->hw_frames_ctx->data;
+-    *hwaccel_picture_private = ff_refstruct_alloc_ext(hwaccel->frame_priv_data_size, 0,
+-                                                      frames_ctx->device_ctx,
+-                                                      hwaccel->free_frame_priv);
++    if (hwaccel->free_frame_priv) {
++        AVHWFramesContext *frames_ctx;
++
++        if (!avctx->hw_frames_ctx)
++            return AVERROR(EINVAL);
++
++        *hwaccel_picture_private = ff_refstruct_alloc_ext(hwaccel->frame_priv_data_size, 0,
++                                                          frames_ctx->device_ctx,
++                                                          hwaccel->free_frame_priv);
++    } else {
++        *hwaccel_picture_private = ff_refstruct_allocz(hwaccel->frame_priv_data_size);
++    }
++
+     if (!*hwaccel_picture_private)
+         return AVERROR(ENOMEM);
+ 
+-- 
+1.8.3.1
\ No newline at end of file
diff --git a/mingw-w64-ffmpeg/PKGBUILD b/mingw-w64-ffmpeg/PKGBUILD
index c5bb455c87..7af00eec7d 100644
--- a/mingw-w64-ffmpeg/PKGBUILD
+++ b/mingw-w64-ffmpeg/PKGBUILD
@@ -69,14 +69,16 @@ source=(https://ffmpeg.org/releases/${_realname}-${pkgver}.tar.xz{,.asc}
         "pathtools.c"
         "pathtools.h"
         "0005-Win32-Add-path-relocation-to-frei0r-plugins-search.patch"
-        "0009-wrong-null-type.patch")
+        "0009-wrong-null-type.patch"
+        "0015-guard-null-hw-frames-ctx.patch")
 validpgpkeys=('FCF986EA15E6E293A5644F10B4322F04D67658D8')
 sha256sums=('488c76e57dd9b3bee901f71d5c95eaf1db4a5a31fe46a28654e837144207c270'
             'SKIP'
             'ebf471173f5ee9c4416c10a78760cea8afaf1a4a6e653977321e8547ce7bf3c0'
             '1585ef1b61cf53a2ca27049c11d49e0834683dfda798f03547761375df482a90'
             '8c74e9b5800dbb41c33a60114712726ec768ad6de8f147c2eb30656fd4c899cc'
-            'f76048e6e1944e15f646a52b75e75bc8906ca80f2a3124fba6a2050722750447')
+            'f76048e6e1944e15f646a52b75e75bc8906ca80f2a3124fba6a2050722750447'
+            'ddad247ff44287b5d0089b5b910b4ba0272404c71b2ffb127e3cf833e8b1cb74')
 
 # Helper macros to help make tasks easier #
 apply_patch_with_msg() {
@@ -100,6 +102,9 @@ prepare() {
     0005-Win32-Add-path-relocation-to-frei0r-plugins-search.patch
 
   apply_patch_with_msg 0009-wrong-null-type.patch
+
+  # https://github.com/msys2/MINGW-packages/pull/19050#issuecomment-1810884473
+  apply_patch_with_msg 0015-guard-null-hw-frames-ctx.patch
 }
 
 build() {