Why is exported MP3 file longer than original MP3 file?

[bkelorian]

Here's what I did:

1. Opened and Edited/trimmed an MP3 file (mono, 48 kHz, 24-bit PCM) from 1.176 seconds in length down to 1.139 seconds.

2. Export file to MP3 (mono, 256 kbps 48 kHz and using LAME3.97 with ID3 Tag v2.3)

3. Open exported file from step 2 above and find that it is 1.176 again with an inserted blank or silence (about .037 seconds long) on the front end of the wave form.

How do I get Audacity to not add in silence at the beginning of an exported MP3 file???
(and, yes having the .037 seconds removed is important to this project)

Is this something that MP3's just do? Or, is there an editor out there (besides mp3trimmer - tried it but not happy with results) that will allow audacity style editing?

[steve]

How do I get Audacity to not add in silence at the beginning of an exported MP3 file???

There's only one way to do that - don't export as MP3.
One of the limitations of the MP3 format is that there is always a short bit of silence added to the beginning (regardless of what encoder is used - it's a limitation of the format).

Other formats such as OGG, WAV, FLAC, AIFF don't do that.