In LAN mode, some MP4 playback is very choppy.

mpv Information

mpv v0.40.0-dev-g2e5e2938d Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Nov 10 2025 08:05:24
libplacebo version: v7.357.0
FFmpeg version: bebbdca
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

Other Information

- Windows version: 11
- GPU model, driver and version: navida 2060 super
- Source of mpv: mpv-x86_64-pc-windows-msvc in nightly.link
- Latest known working version: no
- Issue started after the following happened: always

Reproduction Steps

Put the mp4 in my nas with http server, and play the url with mpv.

Expected Behavior

The playback should not choppy.

Actual Behavior

The playback is very choppy.

And the total cache time is always less than 1s.

If I remux the mp4 to mkv (use Mkvtoolnix), then the issue is gone.

Log File

output.txt

Sample Files

https://drive.google.com/file/d/1diN94Wx7kbbELmwKbAC6xWT678vqRzIy/view?usp=drive_link

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.

Start by reviewing output.txt and reproducing playback of the supplied MP4 over the NAS HTTP server in mpv on Windows 11. Compare the choppy MP4 playback and cache time with the remuxed MKV case; done means the supplied MP4 no longer plays choppily under the reported LAN conditions.