MP4 file has no sound after clearing the ID tags

[Nineteen]

Hi,
Yesterday I cleared the ID tag of a MP4 video file (from options-> ID Tag -> Clear ) and now I realized the MP4 file plays without sound in my VLC player. I tried also some other players but the result is the same. Could someone help me? Thanks in advance.

[Nineteen]

That's very strange. The video is actually a recording of my screen but it seems that the audio from other MP4 files (not recordings) I cleared the ID-Tags plays normally. :(

[Porcus]

Sounds very strange. What does VLC say when you hit Ctrl-J?

ffmpeg can give you information about the streams. ffmpeg -i <filename>.

[Nineteen]

Hi,
Here's what I get from MediaInfo:

General
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 45.2 MiB
Duration : 8mn 22s
Overall bit rate mode : Variable
Overall bit rate : 754 Kbps
Encoded date : UTC 2013-12-26 22:43:55
Tagged date : UTC 2013-12-26 22:43:55

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L3.0
Format settings, CABAC : No
Format settings, ReFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 8mn 22s
Source duration : 8mn 22s
Bit rate : 625 Kbps
Width : 640 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Variable
Frame rate : 30.000 fps
Minimum frame rate : 30.000 fps
Maximum frame rate : 30.030 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.068
Stream size : 37.5 MiB (83%)
Source stream size : 37.5 MiB (83%)
Language : English
Encoded date : UTC 2013-12-26 22:43:56
Tagged date : UTC 2013-12-26 22:43:56
mdhd_Duration : 502633

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 8mn 22s
Source duration : 8mn 22s
Bit rate mode : Variable
Bit rate : 126 Kbps
Maximum bit rate : 169 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 7.53 MiB (17%)
Source stream size : 7.53 MiB (17%)
Language : English
Encoded date : UTC 2013-12-26 22:43:56
Tagged date : UTC 2013-12-26 22:43:56
mdhd_Duration : 502666

VLC recognizes two streams however there's no audio playback.
I imported the file back into Camtasia but it didn't show the audio stream so I couldn't do anything.
Also, I extracted the audio but I couldn't convert it nor play it. It seems corrupted.

Anyway I think nothing can be done now. Audio is lost forever. :(

[Porcus]

[...]
Encoded date : UTC 2013-12-26 22:43:56
Tagged date : UTC 2013-12-26 22:43:56

Strange, it doesn't even say it has been changed ever ...

Tried ffmpeg?

ffmpeg -i filename.mp4 -acodec copy filename_audioonly.m4a

Error messages?