Audacity Forum

Hi,
I'm trying the 1.3.7 (unicode) version and it seem to have this strange behavior:

Steps to reproduce:
1) Create a new click track;
2) Export the track to an mp3 file;
3) Import the previously exported file to a new track;
4) Play the two tracks.

As you can see, is there a little delay between the sounds (56 ms in my case).
This is a problem for an audio recording application I'm developing...
Can you help me to solve this problem?
Thanks in advance.

This is due to a limitation of the MP3 format.
All mp3 files have a short lead-in before the original audio data.

Cool Edit Pro (Syntrillium) got round this by modifying the MP3 format to create their own "CEL" format. For users of other software (including Audacity) you can either export as WAV, or if you specifically want to use a compressed audio format, use OGG. Neither OGG, FLAC or WAV have this problem.

Many thanks for your reply,
this make a bit more complicated what i'm doing...

Can you point me to some docomentation about ?
I'm searching for a workaround in my application, so I need to know some details like:
- is the length of this "extra time" constant or it depend on the computer is making the mp3 compression?
- can my application relies on the presence of this short lead-in in all MP3 files ?

Thanks

(Sorry, I realized this is not the best place for this tread but initially i have attributed the incorrect behavior to the 1.3.7 version)

gibbo wrote:Can you point me to some docomentation about ?

I would start with Wikipedia. If the information isn't there, there will probably be links to relevant sites.

Any reason that you can't use Ogg Vorbis?
The sound quality of Ogg is bit better than MP3 at equivalent bit rates, and it is open source so that avoids the restricted licensing issues that go with MP3.