How to remove 50% length of tracks ?

I have few hundreds imported tracks in Audacity. Now, I want to keep 50% length of tracks from the start.
For example: if length of track is from 0 —> 10 seconds. After processing, the length of track is from 0 —>5 seconds. How do do it with multiple tracks. Thank you very much ! :slight_smile:

I presume that the files are different lengths?
What format are the files and what format do the trimmed files need to be?

Audacity has a simple batch processing mechanism called “Chains”. It has some strict requirements / limitations (such as, all the files must be in the same folder). Have a play with Chains - do you think this will work for you if we can adapt the “Trim / Extend” plug-in to work with percentage length?
See these links:

Yes, the files are different lengths. The format of files is mp3 and mp3 is format of trimmed files. Thank you for giving above links :slight_smile:

Are you aware that the length of MP3s is imprecise?
One of the limitations of the MP3 format is that it does not define the overall encoder/decoder delay. A consequence of that is that there is always a few milliseconds of padding at the start of an MP3 file. Will that matter to you?

Another issue is that MP3 is a “lossy” compressed format. The encoding method discards some of the information in order to reduce the file size, which results in some loss of quality, This quality loss is cumulative - every time the audio is encoded, a bit more sound quality is lost, and it is impossible to recover the lost sound quality. Audacity needs to decode MP3s before it can work on them - the files are decoded on import, which means that when exported as MP3 they must be re-encoded, which reduces the sound quality. Will that matter to you?