Saving as MP4 Muxer - no audio

[braaad]

The.mp4 created by Avidemux has no audio, even though the preview does. Mov's play as expected, with audio. What am I not doing?

[eumagga0x2a]

The.mp4 created by Avidemux has no audio

No audio track included into the resulting MP4 file? Or audio track present but not played by an unspecified video player? MOV supports much more codecs than MP4 does.

If it is the former, please make sure you have not suppressed info messages and warnings in Avidemux preferences (Message level: Display all alerts) and check that the audio track you try to mux into MP4 container is supported by QuickTime. In any case, make sure you use the latest build (unless you build from source yourself, try the latest one from https://www.avidemux.org/nightly/osx_monterey/).

If the issue is still persists, please provide specific info (the output of mediainfo) for the source video and for the resulting mp4 file as well as Avidemux project script (you may anonymize paths and file names it contains).

[braaad]

Thanks for your quick reply! Merry Christmas BTW 😎

No audio track included into the resulting MP4 file?

Correct- when playing MP4 in QuickTime, VLC, or from my iPhone there's no audio. But when I play in Avidemux, before saving, the audio plays just fine.

please make sure you have not suppressed info messages and warnings in Avidemux preferences (Message level: Display all alerts)

Alerts are set to display in my prefs

check that the audio track you try to mux into MP4 container is supported by QuickTime

Yes, my MP3 plays in QT

In any case, make sure you use the latest build

Downloaded 2.8.2

If the issue is still persists, please provide specific info (the output of mediainfo) for the source video and for the resulting mp4 file as well as Avidemux project script (you may anonymize paths and file names it contains).

I'm not sure how to get the mediainfo or project script, but here's the Properties:

=====================================================
Video
=====================================================
Codec 4CC:         H264
Image Size:         1280 x 2304
Aspect Ratio:         1:1 (1:1)
Frame Rate:         24.000 fps
Average Bitrate:      23587 kbps
Total Duration:         00:00:17.999
Pixel format:         YUV 4:2:0, 8-bit
Color range:         Limited (MPEG)
Color primaries:      BT.709
Transfer characteristics:   BT.709
Color space:         BT.709

=====================================================
Video Codec Extradata
=====================================================
Size:            42
Extradata:         01 64 00 1F FF E1 00 19 67 64 00 1F AC D9 40 50 01 21 A1 00 00 03 00 01 00 00 03 00 30 0F 18 31 96 01 00 06 68 EF 82 F2 C8 B0

=====================================================
Audio (1 active track)
=====================================================
Codec:            MP3
Channels:         Stereo
Bitrate:         40000 Bps / 320 kbps
Frequency:         44100 Hz
Total Duration:         00:00:18.050

[eumagga0x2a]

Code Select Expand

=====================================================
Audio (1 active track)
=====================================================
Codec:            MP3

Merry Christmas!

Indeed, I can confirm that QuickTime or rather underlying operating system infrastructure at least on macOS (probably on iOS / iPadOS as well) is uncapable of detecting and playing MP3 or MP2 audio tracks in MP4 containers. In MOV containers, MP3 audio tracks are tagged differently from MP4 standard, in a way macOS understands.

In MP4, at least in those created by libavformat – the FFmpeg library Avidemux uses under the hood – MP3 is tagged like many other audio codecs as "mp4a" with the exact codec specified in esds (elementary stream descriptor) atom which macOS seems either to ignore or to misparse. In MOV, MP3 is tagged as ".mp3". I cannot tell whether FFmpeg violates any standard here. More likely, macOS simply doesn't bother to support anything Apple own software doesn't produce by default.

Long story short: Avidemux cannot do anything to work around this Apple bug or limitation. Either re-encode all MP3 audio tracks to AAC when you want to stick with MP4 container or use MOV instead.

BTW, mpv on macOS handles MP4 with MP3 audio tracks just fine. I am very surprised to hear that VLC stumbles (probably there is some setting to not rely on macOS infrastructure here).

[braaad]

Thanks for the reply! I don't mind exporting mov, although I prefer MP4. I'll try encoding the audio as AAC and see if that fixes anything. Anyway, not a big deal and I really appreciate the support. Great product!