audacity and infraexpress

[robby]

Hi,

I'm not an expert on making audio files, so I may have a stupid question...

I've made an audio file with Audacity with the default settings. I exported to MP3 to save disk space. I always used Nero to create audio files (WAV?) to play the records in a conventional CD player. No problems with that. Now I want to use InfraExpress to do the same. Everything goes fine to a certain point. The MP3 files are converted with Lame to audio format but when I is going to burn I get an error saying there is a error saying there is an incorrect audio coding.

I have contacted Christian Kindahl, the maker of Infraexpress and he explained me that the file have meet the CDDA audio specification. This means that the audio must have two channels, 16-bit samples and a sample rate of 44100 Hz. When I open the MP3 files in Audacity the seem to meet this specifications. After importing the MP3 file in Audacity the info penal says Mono, 44100Hz 16-bit PCM. (It's mono but on two channels I think).

Does anybody have any idea in what I'm doing wrong and how to correct it?

Thanks,

Robby

[steve]

he explained me that the file have meet the CDDA audio specification. This means that the audio must have two channels, 16-bit samples and a sample rate of 44100 Hz.

For the CDDA audio specification they must be uncompressed audio - in other words WAV (or AIFF) files.

You need to decode (un-compress) the files before putting them into infraexpress.

To save disk space, you may want to consider using FLAC format. It does not compress audio as much as MP3 or OGG, but it is lossless. You will still need to decode a FLAC file before putting it into infraexpress, but FLAC files can be encoded/decoded as often as you like without any loss in sound quality. FLAC will usually compress audio to about 50% of the original file size. When you decode a FLAC file, the audio is identical to the original. "FlacDrop" is a useful utility for quickly and easily encoding and decoding FLAC files. Another option would be to buy an external hard drive so that you have more storage capacity. 500GB external drives are quite inexpensive these days.

[robby]

Hi Steve,

Thanks for your reply.

I'm not sure if I understand what you're saying. I understand that before Infra-Express can burn a audio-file it has to be in a WAV format. But when the option "create audiofile" in Infra-Express is chosen it will automatically start Lame to decode the MP3 to WAV and save it to a temp folder. This WAV file will then be used to burn the compilation to a audio disk. Well, at least this is what happens to a commercial MP3 file. In my case the MP3 files created by Audacity are decoded in the Temp folder but an error occurs when the WAV file is about to be burned to the compilation. (Saying: "incorrect audio coding). So I think I used some wrong settings to export the Audacity file to the MP3 format... It is the only thing I can think of because commercial MP3 files are being burned correctly by Infrarecorder/Infraexpress to a audiodisk. Nero causes no problems...

Any suggestions what settings could be wrong? I used only one microphone to record the original sound, assuming Audacity is then creating a mono recording on two channels. Perhaps this assumption is wrong?

Robby

[steve]

assuming Audacity is then creating a mono recording on two channels. Perhaps this assumption is wrong?

That could be the problem. If you export a mono recording, Audacity will export it as a mono file. This is normally a good thing because mono MP3's are much smaller than stereo MP3s.

You may be able to work around this by adding a silent stereo track before exporting.

As you have probably guessed, I don't use infraexpress, so I'm having to guess at what it is doing. Nero and K3B which I use are both pretty good at automatically converting audio to the correct format.

Another possibility is that infrexpress may be having trouble with the ID3 Metadata that Audacity uses, in which case you may need to manually decode your MP3s to WAV before burning with infrexpress.

If you know that you are going to burn audio to CD, it is better to Export from Audacity as 16bit 44100Hz stereo WAV. This will avoid loss in sound quality from the MP3 encoding. You can always encode as MP3 (or OGG or FLAC) later if you wish.

[robby]

OK thanks,

For others... I've find out that the burning program Cdrtfe http://cdrtfe.sourceforge.net/ is able to do the decoding correctly. It is also Open source and has the same functionality as infrarecorder but the UI is a bit less nice.

Robby