mpv crashes on exit if using AMF decoder

mpv Information

mpv v0.40.0-495-g122abdfec Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Dec 16 2025 00:07:26
libplacebo version: v7.358.0 (v7.351.0-100-g3fc2736-dirty)
FFmpeg version: N-122178-g7ee5c907e
FFmpeg library versions:
   libavcodec      62.23.101
   libavdevice     62.2.100
   libavfilter     11.10.101
   libavformat     62.8.100
   libavutil       60.20.100
   libswresample   6.2.100
   libswscale      9.3.100

Other Information

- Windows version: Microsoft Windows [Version 10.0.26200.7462]
- GPU model, driver and version: Rdeon RX Vega (Driver version 25.8.1)
- Source of mpv: https://github.com/shinchiro/mpv-winbuild-cmake/releases/download/20251217/mpv-x86_64-v3-20251217-git-122abdf.7z
- Latest known working version: not sure
- Issue started after the following happened: not sure

Reproduction Steps

(1) Run mpv.com -vd h264_amf https://test-videos.co.uk/vids/bigbuckbunny/mp4/h264/1080/Big_Buck_Bunny_1080_10s_1MB.mp4 in command prompt (cmd.exe)
(2) Press 'q'
(3) Run echo %ERRORLEVEL%

Expected Behavior

mpv exits without crash. (ERRORLEVEL is 0)

Actual Behavior

The result would be -1073741819 (0xc0000005).

Log File

amf-crash.log.zip

mpv.exe.58628.dmp.zip

Sample Files

No response

I carefully read all instruction and confirm that I did the following:

• I tested with the latest mpv version to validate that the issue is not already fixed.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

The cause

I tracked the issue down and found that the cause is that mpv calls av_buffer_unref() after dlclose() for amfrtdrv64.dll.
So this is not a bug of AMD driver.

The code path to dlclose() is as follows.

Called function			From where
avcodec_free_context()	[video/decode/vd_lavc.c:uninit_avctx()]
  |
  v
ff_codec_close()		[libavcodec/options.c:avcodec_free_context()]
  |
  v
amf_decode_close()		[libavcodec/avcodec.c:ff_codec_close():ffcodec(avctx->codec)->close(avctx)]
  |
  v
av_buffer_unref()		[libavcodec/amfdec.c:amf_decode_close()]
  |
  v
buffer_replace()		[libavutil/buffer.c:av_buffer_unref()]
  |
  v
hwdevice_ctx_free()		[libavutil/buffer.c:buffer_replace():b->free(b->opaque, b->data)]
  |
  v
amf_device_uninit()		[libavutil/hwcontext.c:hwdevice_ctx_free():ctxi->hw_type->device_uninit(ctx)]
  |
  v
dlclose()				[libavutil/hwcontext_amf.c:amf_device_uninit()]

After dlclose(), at vo_thread() exit,

uninit()				[video/out/vo.c:vo_thread():vo->driver->uninit()]
  |
  v
(inside libplacebo.dll)
  |
  v
mp_image_destructor()	[(inside libplacebo.dll)]
  |
  v
av_buffer_unref()		[video/mp_image.c:mp_image_destructor()]
  |
  v
buffer_replace()		[libavutil/buffer.c:av_buffer_unref()]
  |
  v
amf_free_amfsurface()	[libavutil/buffer.c:buffer_replace():b->free(b->opaque, b->data)]
  |
  v
Release()				[libavutil/hwcontext_amf.c:amf_free_amfsurface()]

Here, Release() points inside amfrtdrv64.dll. Then crash.

My conclusion is:
mpv calls FFmpeg API's in a way that FFmpeg does not expect.

Start with video/decode/vd_lavc.c:uninit_avctx(), then trace the shutdown path through video/out/vo.c:vo_thread() and the FFmpeg AMF paths named in the report. Reproduce with the provided mpv.com command and inspect whether teardown ordering leaves libplacebo surfaces referencing amfrtdrv64.dll; done means quitting no longer returns 0xc0000005 and ERRORLEVEL is 0.