[Bug]: MOV to MP4 conversion fails with Apple APAC audio stream (FFmpeg exit code -22) #781

What happened?

When converting iPhone-recorded MOV videos to MP4 or MP4 HEVC, Filee fails with the following error:

The engine reported an error (FFmpeg failed (exit code -22):
Decoding requested, but no decoder found for: apple_apac
Error opening output file C:\Users\ALM\Dropbox\Work\IMG_7460.mp4.
Error opening output files: Invalid argument)

All four tested MOV files fail with the same error.

FFprobe confirms that the files contain a supported AAC stereo audio stream alongside an unsupported Apple APAC four-channel audio stream.

Troubleshooting performed:

• Updated FFmpeg from 8.1 to Filee's recommended 9.0.
• Retried MP4 conversion: failed.
• Retried MP4 HEVC conversion: failed.
• Enabled "Remove the sound" in Filee.
• Retried MP4 conversion: succeeded.

This strongly suggests that Filee attempts to decode the unsupported Apple APAC audio stream instead of selecting the compatible AAC audio stream.

What did you expect?

Filee should successfully convert MOV files to MP4 or MP4 HEVC while preserving the supported AAC stereo audio.

Unsupported audio streams, such as Apple APAC, should be automatically skipped when a compatible audio stream is available.

Users should not need to remove all audio to complete the conversion.

Steps to reproduce

1. Open Filee on Windows 11.
2. Add an iPhone-recorded MOV file containing both AAC stereo audio and Apple APAC four-channel audio.
3. Select the MP4 conversion preset.
4. Set the video codec to H.264, quality to Balanced, maximum height to Original, and audio bitrate to Automatic.
5. Leave "Remove the sound" unchecked.
6. Start the conversion.
7. Observe FFmpeg exit code -22 and the apple_apac decoder error.
8. Enable "Remove the sound" and retry the same file.
9. Observe that the conversion succeeds without audio.

The same issue occurs when selecting MP4 HEVC.

Files involved

Four MOV files tested:

• IMG_7460.MOV
• IMG_7461.MOV
• IMG_7462.MOV
• IMG_7458.MOV

All files have the same stream structure.

Video:

• Codec: H.264 (High Profile)
• Resolution: 1920 × 1080

Audio:

• Stream 0: AAC LC, stereo, codec tag mp4a
• Stream 1: Apple APAC, 4 channels, codec tag apac

Additional streams:

• Streams 3–8: Unknown data streams

FFprobe output for IMG_7462.MOV:

index=0|codec_name=aac|codec_tag_string=mp4a|channels=2
index=1|codec_name=unknown|codec_tag_string=apac|channels=4

The exact file sizes have not been recorded. A sample MOV file can be provided if needed.

Filee version

2.2.0

Operating system

Windows 11 Pro (64-bit)

Engines page status

Log

Filee version: 2.2.0
OS: Windows 11 x64 (build 26200)

All four MOV files fail with the same FFmpeg error:


WARN JobQueue: Converting IMG_7460.MOV failed
System.InvalidOperationException: FFmpeg failed (exit code -22):
Decoding requested, but no decoder found for: apple_apac
Error opening output files: Invalid argument

at Filee.Engines.Media.FfmpegConverter.RunPassAsync(...) in FfmpegConverter.cs:line 521
at Filee.Engines.Media.FfmpegConverter.RunPassesAsync(...) in FfmpegConverter.cs:line 498
at Filee.Engines.Media.FfmpegConverter.RunWithFallbackAsync(...) in FfmpegConverter.cs:line 474
at Filee.Engines.Media.FfmpegConverter.ConvertAsync(...) in FfmpegConverter.cs:line 206


The same error occurs for IMG_7458.MOV, IMG_7461.MOV and IMG_7462.MOV.

At 22:57:01, Filee started another conversion using the `to-mp4` preset with "Remove the sound" enabled. This conversion succeeded.

The files contain both AAC stereo audio (supported) and Apple APAC four-channel audio (unsupported).

**Expected behavior:** Filee should select the supported AAC audio stream and automatically skip the unsupported Apple APAC stream, preserving audio in the converted MP4.