No audio tracks showing up (but audio plays in VLC)

[jlyon1515]

I'm having trouble combining several MP4 files. The video is fine, but Avidemux is saying there are no audio tracks. The individual files all play with audio in VLC fine though.

Maybe Avidemux doesn't support this audio type?

Here's the media info:

Audio
ID                      : 482 (0x1E2)
Menu ID            : 1 (0x1)
Format               : AAC
Format/Info       : Advanced Audio Codec
Format version   : Version 4
Format profile    : LC
Muxing mode     : ADTS
Codec ID           : 15
Duration            : 39 min 7 s
Bit rate mode                : Variable
Maximum bit rate          : 177 kb/s
Channel(s)                    : 2 channels
Channel positions          : Front: L R
Sampling rate                : 44.1 kHz
Frame rate                     : 43.066 FPS (1024 spf)
Compression mode       : Lossy
Delay relative to video   : -36 ms
Language                      : English

In the past I've seen the first reply asking to provide a sample file. In hopes that it will help, I've uploaded a file here:
https://www.dropbox.com/s/ztxu3tbsobj8gai/3.mp4?dl=0

Thanks for any help you can provide.

[Jan Gruuthuse]

Confirmed: avidemux 2.6.18 commit  c255a13 is not detecting the audio track:

Simple loading:
file: 3.mp4, size: 10142224
found 1 files
Done
[TsPacket] Detecting TS/TS2...
[TsPacket] Score : 188:20, 192:1 out of 20
[TsPacket] Probably TS1 (188)...
[tsDemuxer] Loaded 1
[ADM_PP] 05:25:48-953  Initializing postproc
[cleanup] 05:25:48-953  Deleting post proc
[update] 05:25:48-953  updating post proc
[update] 05:25:48-953  Disabled
[addFile] 05:25:48-953  Clearing video filters
[ADM_vf_clearFilters] 05:25:48-953  clear filters
[Editor] *** NO AUDIO ***

weird is, mediainfo reports
Video:

Frame rate                               : 29.970 (30000/1001) fps

Audio:

Frame rate                               : 43.066 fps (1024 spf)

no idea if this has any to do with it.

vlc reports audio track as: MPEG AAC Audio (mp4a)

[mean]

The file is a MPEG TS file
It does not contain PAT/PTM so brute force is used to detect the tracks
Brute force is not very good at detecting audio

[mean]

use mkvmerge to convert it to a mkv (it's very fast, no quality loss at all)
the resulting mkv can be opened without troubles

[Jan Gruuthuse]

confirmed, passing through mkvtoolnix, then loading the newly saved .mkv has avidemux detecting the audio track.

[jlyon1515]

Awesome, thanks for the speedy responses! I'll look into it this. The only drawback is that there are 238 MP4 files that I was trying to combine. All of them have this same issue. So converting all the files will take a while, but it's obviously doable!

Again, thanks for the quick responses. It's great to see such an active community!

[jlyon1515]

An update. Texting just 4 of the files, I converted them all toe MKV files with MKVToolNix. I then tried joining them via Avidemux. Unfortunately at every seam point of the files, there was a weird audio and video hiccup. I was surprised by the video hiccup because when I had previously used Avidemux when it didn't find any audio tracks, the joined file had no video problems. In the end, I found the final solution via this video:
https://www.youtube.com/watch?v=1Xf1DfvVJbs

Though running the exact command line stated in the video didn't work. The line in the video:
ffmpeg -f concat -i mylist.txt -c copy output.mp4
gave me an error statement and said conversion failed.

Thankfully, the error statement told me what I needed to add to the command line. So here is the perfectly working line I used (just posting here for others in the future):
ffmpeg -f concat -i mylist.txt -bsf:a aac_adtstoasc -c copy output.mp4