Audacity is the wonderful open-source audio-processing program that I use every day. I use it for a couple of reasons.
First, I use Audacity to record and prepare my own podcast shows, which are mostly for Hacker Public Radio. I seem to have done over 200 shows for them, and I am still actively recording shows, and I expect to continue as long as I can, though at the age of 69 I can see that there may come an end sooner rather than later. And Audacity does a great job for me. I just plug in my Blue Snowball microphone, open Audacity, and press the Record button. When I am done I add a little volume boost, save the project, then export the FLAC file for upload to Hacker Public Radio.
Second, I like to listen to podcasts speeded up. I listen to a lot of podcasts, and even when I weed out the ones that just go on for too long, it is still hard to keep up. I know that people who use smartphone apps can speed up podcasts in the app, which is fine, but I don’t listen to podcasts on my phone. I use small, inexpensive MP3 players and this lets me save my phone’s battery so I get through the day without problems. So my method is to download my podcasts using GPodder on my Kubuntu box, and about once a day I will delete the ones I have finished listening to and prepare a new bunch to load on the player. And Audacity is what I use to prepare the files. I created a “chain” some years back on the old version of Audacity, which would take the files, speed them up by 70%, boost the volume a bit, and then export the finished file. And I could do it as a batch process on a whole directory of files. It would open the files one at a time, apply the “chain”, and then move on the the next file. This was very handy.
Then I made the jump from Kubuntu 18.04 to 20.04. I tend to stick to LTS releases and be fairly conservative because I would rather use my computer to do things than spend time fixing software issues, and LTS releases work well for me in this respect. In fact, I did not move from 18.04 to 20.04 until February of 2021. And with the OS upgrade came the software upgrades, including Audacity. And when I went looking for chains, they weren’t there! I did some investigating on the Web and found that they were replaced by “macros”, and instead of being on the File menu they were on the Tools menu, which is reasonable enough I guess. I looked in the Tools menu, found Apply Macro, and when I opened that I found that my chains had all been moved over to the Macros, which was great since I did not have to recreate any of them, not that it would be all that difficult to do. But I could only apply a macro to one file at a time. The process seemed to be that I had to open a file, then apply the macro. And when I tried to do that to a directory with about 20 files in it, each file opened seperately in its own window (a big mess right there), then I had to go through them one at a time to apply the macro and then close the window. Ugg.
As I considered this, it did occur to me that in all likelihood I was doing it all wrong, and that the capability was still there. I started by going to the Audacity Forum, where I did see some references to batch processing, but none of them ever explained how to do that. So I started searching for “audacity batch processing”, and the first few results got me nowhere. They either went back the to the page that referred to batch processing without explaining how to do it, or they went back to the older version with “chains”. But then I found a YouTube video called Audacity Macros – Easily Apply Effects to Multiple Files, and that was where I got my answer. On the Tools menu there was another option, called simply “Macros…”. Selecting this opened a window called Manage Macros, and on the bottom there was a section to “Apply Macro to” and you could either do it to the current project, or to a group of files. So it was there all along, I just missed it.