Cannot use custom recording on RetroArch for iOS (App Store)

Is there an existing issue for this?

• This is a bug in RetroArch frontend
• I have searched the existing issues

Description

FIRST, THIS IS NOT A BUG IN RETROARCH FRONTEND, BUT IT'S NOT FROM THE CORES OR GAMES EITHER!

I can't start the recording when trying to use a custom configuration.

I created a custom recording configuration nice_lossless.cfg:

vcodec = libx264rgb
acodec = flac
format = mkv
pix_fmt = rgb24
video_preset = ultrafast
video_tune = animation
sample_rate = 48000

Saved the file in ~/Documents/RetroArch/records_config/nice_lossless.cfg.

On "RetroArch" App, I went to "Settings" -> "Recording".

• Option "Recording Quality" I changed to "Custom".
• Option "Custom Recording Configuration" I selected my custom config: ~/Documents/RetroArch/records_config/nice_lossless.cfg.

I'm trying to record a Sega Master System game with "Genesis Plux GX Wide".

I can successfully record using any pre-made preset, such as the "lossless" one that comes with RetroArch. However, it records the audio at 44100 Hz, even though I set the audio output to 48000 Hz, which is what made me want to create a custom recording file.

retroarch__2025_02_11__21_32_13.log

Expected behavior

Let the video recording be done just like with the existing presets, respecting the file's settings.

Steps to reproduce the bug

At description.

Version/Commit

1.20.0

Bisect Results

ab3b175848

Present in the nightly version

I don't know

Platform & operating system

iOS 18.3.1

Affected Cores

All

Environment information

No response

Relevant log output

[INFO] [Recording]: Custom timing given: FPS: 59.92, Sample rate: 44100.00
[INFO] [Recording]: Recording to /private/var/mobile/Containers/Data/Application/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/Documents/RetroArch/records/Golvellius - Valley of Doom (UE) [!]-250211-212538.mkv @ 256x192. (FB size: 284x240 pix_fmt: 0)
[INFO] [FFmpeg] Loading FFmpeg config "/private/var/mobile/Containers/Data/Application/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/Documents/RetroArch/records_config/nice_lossless.cfg".
[ERROR] [Recording]: Failed to start recording.
[INFO] [Recording]: Custom timing given: FPS: 59.92, Sample rate: 44100.00
[INFO] [Recording]: Recording to /private/var/mobile/Containers/Data/Application/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/Documents/RetroArch/records/Golvellius - Valley of Doom (UE) [!]-250211-212538.mkv @ 256x192. (FB size: 284x240 pix_fmt: 0)
[INFO] [FFmpeg] Loading FFmpeg config "/private/var/mobile/Containers/Data/Application/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/Documents/RetroArch/records_config/nice_lossless.cfg".
[ERROR] [Recording]: Failed to start recording.

Start with the attached log and the custom records_config/nice_lossless.cfg path, comparing the custom-configuration flow with the working built-in presets on iOS. Reproduce the failure using the listed settings and verify that custom recording starts and honors the requested 48 kHz audio rate.