MP3 files: recommended bitrate, and how to batch-convert

[shmu26]

I have a large collection of lectures in MP3 format, and I have two questions:

1 what is the recommended bitrate for lectures? I don't want to lose quality, but I also don't want to waste storage space.

2 how can I batch-convert them in a way that will preserve the folder structure?

 

[elbert]

Best bit rates is 128~192 and I would suggest audacity. You may want to get Lame mp3 codec.
http://www.audacityteam.org/
http://lame.sourceforge.net/

 

[Hlsgsz]

Unless you have special player device requirements, go for AAC 48kbps.

Here's open surce conversion software: https://sourceforge.net/projects/lamexp/

 

[hang-the-9]

I have a large collection of lectures in MP3 format, and I have two questions:

1 what is the recommended bitrate for lectures? I don't want to lose quality, but I also don't want to waste storage space.

2 how can I batch-convert them in a way that will preserve the folder structure?

If they are already in MP3 format I suggest leaving them as is unless they are large or are setup in high bit rates.

For just speech, you can probably deal with 64 kb/s or even lower, set it for mono instead of stereo and have things sound good.