--screenshot-template='%{title}' only half expanded (to `${?media-title: ….jpg`

mpv Information

mpv 021c5de Copyright © 2000-2024 mpv/MPlayer/mplayer2 projects
 built on May 26 2024 16:07:27
libplacebo version: v7.349.0
FFmpeg version: git-2024-05-26-63697d3
FFmpeg library versions:
   libavutil       59.20.100
   libavcodec      61.5.104
   libavformat     61.3.104
   libswscale      8.2.100
   libavfilter     10.2.102
   libswresample   5.2.100

and

mpv 0.37.0 Copyright © 2000-2023 mpv/MPlayer/mplayer2 projects
libplacebo version: v6.338.2
FFmpeg version: 6.1.1-3ubuntu5
FFmpeg library versions:
   libavutil       58.29.100
   libavcodec      60.31.102
   libavformat     60.16.100
   libswscale      7.5.100
   libavfilter     9.12.100
   libswresample   4.12.100

Other Information

- Linux version: Ubuntu 24.04.1 LTS
- Kernel Version: 6.8.0-41-generic #41-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug  2 20:41:06 UTC 2024
- GPU Model: Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b)
- Mesa/GPU Driver Version: OpenGL version string: 4.6 (Compatibility Profile) Mesa 24.0.9-0ubuntu0.1
- Window Manager and Version: xfce 4.18
- Source mpv: ubuntu & fruit repo
- Introduced in version: unknown

Reproduction Steps

Trying to find a suitable screenshot template, i stumbled over this glitch that %{title} is only being half expanded.
To reproduce, play any file with mpv -v --screenshot-template='%{title}' and press s to take a snap than check the name.

example: mpv --no-config -v --screenshot-template='%{title}' --gpu-debug --log-file=output.mpv.txt https://www.youtube.com/watch?v=3cdt-aECOCg

Expected Behavior

That the title is filled into the filename.

Actual Behavior

Actual file name created is ${?media-title:${media-title}}${!media-title:No file} - mpv.jpg

Log File

• v0.37: output.mpv.txt
• v0.38-021c5de: output.mpv.txt

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.

Start by tracing the --screenshot-template option and the screenshot action triggered by the s key, using the linked output.mpv.txt logs to follow how %{title} is expanded. Reproduce with the command shown and verify that the resulting filename contains the media title rather than the unexpanded conditional template.