UPDATE 2024-12-04: This is no longer a work-in-progress. This experiment is done. Keeping the notes below as-is, and archiving the repository for reference.
Use Azure Durable Functions to process audio with the SoX utility.
NOTE: This is a work-in-progress learning project. It is not ready for consumption (unless you want a bellyache).
After completing a Pluralsight course called Azure Durable Functions Fundamentals by Mark Heath, I wanted to do my own project to build my understanding of the topic. I have been using a set of shell scripts that run open source audio utilities to automate processing audio from MP3 files. The files are downloads of a few podcasts where I think the audio levels could use a boost. My scripts also produce a couple faster (increased tempo) versions of the audio (in case the pace of the podcast could use a boost too). I wrote these scripts years ago, but they still work.
This local automation process seemed like a good candidate for an Azure Functions project. Because it processes audio using external tools, the workflow could be similar to Mark's Durable Functions Video Processor Demo from his course.
My FunciSox application was built following a lot of the patterns from Mark's course. I did not use any of his code directly, though much of mine will be similar.
Why this project is not ready for consumption:
I am using the same versions of the audio utilities (sox.exe, lame.exe, id3.exe) as in my local process. I had trouble running the current versions of those executables in the Azure Functions environment (actually, I had trouble running the old versions, but eventually sorted that out). I am not going to make my copies of the executables available for download. Anyone trying to use the FunciSox project, as it stands, will have to find versions of those utilities and incorporate them into their project.
Mark Heath's Azure Functions Links
2022-04-13
Just having the Table attribute in SendDownloadAvailableEmail did not result in the Downloads table being created automatically. The workflow would fail because the table did not exist. I used Microsoft Azure Storage Explorer to create an empty Downloads table. After that the workflow would successfully add rows to the table.
Table Support in Azurite is in PREVIEW. Maybe it behaves differently from the (now deprecated) Azure Storage Emulator. Maybe I misunderstood when I expected using the Table attribute would cause the table to be created if it did not exist.
2022-04-14
For sox.exe to convert from mp3 format libmad.dll is required. That DLL is not part of the SoX project and is not provided in the download. I found a version of libmad.dll that I complied from source in 2009. I copied it to the Tools directory but it did not work with the more recent sox.exe. I had to use the version of sox.exe (SoX v14.3.0) from the same era as the found libmad.dll.