Upgrade FFmpeg version

[mikeyaworski]

TLDR

Seeking an HLS playlist that uses fMP4 segments does not work on nightly builds of MPV for Windows. This is because nightly builds use FFmpeg 7.1 and there is a bugfix in FFmpeg v8 which addresses it.

I'll also leave my investigation below for future readers.

---

My Problem

I'm wondering if it's straightforward to upgrade FFmpeg in the nightly builds from v7 to v8 since there is an important bugfix in v8. The bug is that seeking in HLS streams that use fMP4 segments (example below) does not work. It will play the stream just fine if you let it run from the beginning, but seeking to any point past the cache will not load segments. Tested on both Mac and Windows.

This is due to a bug in FFmpeg. It was tracked here https://trac.ffmpeg.org/ticket/7359 and patched here FFmpeg/FFmpeg@380a518. This eventually made its way into release 8.0, but was not part of release 7.1.2. The patch was in Nov 2024, and "7.1.2 was released on 2025-09-14. It is the latest stable FFmpeg release from the 7.1 release branch, which was cut from master on 2024-09-24." (https://www.ffmpeg.org/download.html)

Questions:

1. So, my option to avoid this bug is to use a third party build for mpv (which I don't want to do because I prefer first party for trust). Or I can wait until the nightly build upgrades FFmpeg to v8. I'm wondering if it's easy to bump the version, or if I should just use a third party build in the meantime.
2. Is there alternative way for me to upgrade the FFmpeg version myself, without it being super involved? Or can I link an existing mpv build to another FFmpeg build? I don't believe so.

---

Context of my findings

My investigation led me to understand:

• FFmpeg is compiled with the MPV build itself and is independent of the FFmpeg you may have on your system
• According to the win32 build script (

  mpv/ci/build-win32.ps1

  Lines 143 to 144 in aa2dad0

  	URL = "https://gitlab.freedesktop.org/gstreamer/meson-ports/ffmpeg.git"
  	Revision = "meson-7.1"

  ), mpv nightly uses this port of FFmpeg (revision 7.1), which is currently 7.1.2 at the time of writing https://gitlab.freedesktop.org/gstreamer/meson-ports/ffmpeg/-/commit/189eba2

   $ mpv -version
   mpv v0.40.0-dev-g7b6fb2bbc Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
    built on Oct 11 2025 10:16:12
   libplacebo version: v7.357.0
   FFmpeg version: 189eba2
   FFmpeg library versions:
      libavcodec      61.19.101
      libavdevice     61.3.100
      libavfilter     10.4.100
      libavformat     61.7.100
      libavutil       59.39.100
      libswresample   5.3.100
      libswscale      8.3.100
  

• This seeking issue was raised with mpv here https://trac.ffmpeg.org/ticket/7359 and it was patched here FFmpeg/FFmpeg@380a518
• https://www.ffmpeg.org/download.html shows the release history of FFmpeg, and that commit did not make it to a release until version 8.

HLS with fMP4 segments example:

https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/index-dvr.m3u8 or

#EXTM3U
#EXT-X-VERSION:6
#EXT-X-TARGETDURATION:10
#ID3-EQUIV-TDTG:2025-10-24T02:05:22
#EXT-X-PLAYLIST-TYPE:EVENT
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-TWITCH-ELAPSED-SECS:0.000
#EXT-X-TWITCH-TOTAL-SECS:10520.000
#EXT-X-MAP:URI="https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/init-0.mp4"
#EXTINF:10.000,
https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/0.mp4
#EXTINF:10.000,
https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/1.mp4
#EXTINF:10.000,
https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/2.mp4
#EXTINF:10.000,
https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/3.mp4
#EXTINF:10.000,
https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/4.mp4
#EXTINF:10.000,
https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/5.mp4
#EXT-X-ENDLIST

You can run it with mpv via:

mpv --demuxer-lavf-format=hls --stream-lavf-o-append=protocol_whitelist="file,http,https,tcp,tls,crypto,hls,applehttp" https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/index-dvr.m3u8

Just to verify this bug is part of FFmpeg itself, I reproduced this issue on FFmpeg 7.1.1:

ffmpeg -ss 30 -to 50 -i https://ds0h3roq6wcgc.cloudfront.net/e052e87e5a4f6b004d85_merytz_315428141271_1761260987/chunked/index-dvr.m3u8 -c copy -bsf:a aac_adtstoasc test.mp4

This will fail on v7 but succeed on v8. If you remove the -ss option, it will succeed on both.