Possibly corrupted MP3 won't play properly in Audacity

Audacity 3 Help Forum Windows
1

I’m using Audacity 2.0.6. I’m on Windows 7 x64 SP1.

I really don’t know anything about audio files, codecs, etc and I’ve never used Audacity before today.

I work as a journalist, and yesterday I conducted an interview on my android phone. I used a third party app - Steady Call Recorder https://play.google.com/store/apps/details?id=com.steadycallrecorder&hl=en_GB to do so.

I sent the file to my computer. I noticed the audio was very choppy - the person I was interviewing is very quiet, and combined with some background noise and their thick accent, it’s almost impossible to understand them in the recording. A friend recommended I try using Audacity to clean the interviewee’s audio up.

However, when I open the file in Audacity (or import it) it plays as a 1 second ‘record scratch’ noise.

I think the file may be corrupted somehow. If I try playing it in MediaMonkey, it comes up as a 0:00 track and therefore doesn’t play anything. In VLC, it plays ok, but if I try skipping forward it goes silent (continuing to play. but with no sound).

The only program I’ve managed to get it working fine in is Media Player Classic. This suggested to me that it might be a problem with the file requiring an unusual codec, for some reason, that MPC has in its library and most other media players don’t. I don’t know why this would be the case however - the file is definitely an MP3.

I installed LAME for Audacity to increase its codec library but it’s made no difference.

I tried running MP3 Validator. It said it’s an ‘unknown file format’ - despite, as I say, it definitely being an MP3. I tried running Codec Installer to see what codec it requires - it said “this file seems corrupted”.

If the file is corrupted, is there any way of diagnosing the corruption and fixing it? If it’s just an unusual type of mp3 (if such a thing exists!) is there a way for me to find out what codec it requires that both Audacity and LAME don’t have, so I can search for it directly?

It’s really important for my job that I can salvage this file for transcription so I’d really appreciate any help. I’m really out of my depth when it comes to audio and codec issues so apologies if anything I’ve said here doesn’t make any sense!

I’d prefer not to upload the actual file for others to look at, as the interview itself contains somewhat sensitive information. If it’s impossible to diagnose the problem without looking at the actual file then let me know and I’ll see if I’m able to work something out.

Thanks all

2

LAME is for writing MP3’s - Audacity already comes with an MP3 decoder that can read MP3.

Try installing FFmpeg ( http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#ffdown ). Then File > Import > Audio… , choose “FFmpeg-compatible files” in “Files of type”, select the file and “open” it.

If that does not help you can examine the file in “MediaInfo” from http://mediainfo.sourceforge.net/en/Download/Windows to see if it really contains MP3 audio. Get the version without installer, because the installer may have malware or adware.


Gale

3

Installing FFmpeg fixed it! Thank you, you’ve been a real life saver :slight_smile:

4

There is a free program called [u]TAudioConverter[/u] that can convert between many different audio formats. You can try converting your file to WAV. (But, I assume TAudioCoverter uses the same open source FFMPEG decoders that Audacity can optionally use.)

If you have a desktop/tower computer with a regular soundcard, you can get the appropriate cable, plug the phone’s headphone output into the soundcard’s line-in, and make an “analog recording” with Audacity. (Most laptops only have mic-in and headphone out.)

the person I was interviewing is very quiet, and combined with some background noise and their thick accent, it’s almost impossible to understand them in the recording.

:frowning: I’m not sure how much Audacity (or any other software) can help… The human brain is a better “speech recognition analyzer” and filter than any software. If you are not sure what was said, you may need to call the interviewee for a clarification.

Some processing may make it “easier” to understand, but I’m not sure it will bring-out anything you can’t understand by listening carefully 3 or 4 times…

There’s probably nothing you can do about the choppy playback.

Of course, you can bring-up the volume, but this will also bring-up the background noise. And, noise removal works best with a constant low-level background noise. If the noise is bad, the noise removal will also remove/damage some of the good audio and sometimes, "the cure is worse than the disease".

I assume the audio player on your Andriod has an [u]Equalizer[/u]. Media Player Classic may also have one, and of course Audacity has an Equalization effect. Try reducing the low-frequencies below 200 or 300 Hz. This will reduce any low frequency noise, and those “bass” frequencies are not important for intelligibility. Boosting frequencies above 3000 or 4000 Hz (treble) will bring-out the “T” and “S” sounds, and this can help with intelligibility. The very-high frequencies above ~8000Hz can be reduced if there is any very-high-frequency noise.

If you can get it open in Audacity, try the Compressor effect and/or the Hard Limiter effect. These processes tend to bring everything toward the same loudness. That is, they will tend to make the quiet parts louder without boosting the already-loud parts. If the noise is in the background this will make it worse, but if the noise is in the foreground it may help to bring the voice up out of the background. (Actually these effects work the opposite way and “push down” the loud parts, so use the Make-up Gain option with the Compressor and Amplify after running the Limiter.)


P.S.

I work as a journalist…

Take notes!!! :stuck_out_tongue:

Try to find out what apps other journalists are using, and test-out the technology before it’s critically needed.

For in-person interviews, I’d suggest a solid-state recorder, maybe with the phone also recording as a back-up. And, take notes. :stuck_out_tongue: I always say, “Computers are the least reliable things we own.” Maybe smart phones are the 2nd least reliable (especially if you are running lots of apps).