How Should I Compress My Files?

What is File Compression?

File compression refers to reducing the size of a recording file – usually by applying a compression algorithm, like the MP3 algorithm, to produce a smaller file that still sounds great. While it's similarly named to dynamic compression, they are not related.

Compression is important on your end, because your files need to be hosted somewhere for people to download (either with Cast or with another host), and also for your listeners because they need to download and store your files while they're listening to them. Larger files are going to take longer to download, use up more of your listener's data plan, and take up more local storage space.

In short: you want the smallest possible file that still sounds good.

Compression Considerations

All computer files can be compressed in two broad ways:

Compression algorithms have all been designed to capitalize on the things that human beings are good and bad at hearing; they aim to alter your recording files in ways that sound nearly the same to the human ear, but result in big file-size savings. In particular, many algorithms have been further optimized to compress the human voice very well without altering its sound. (This is, obviously, what you want.)

If You're Mixing With Cast

Cast's mixer chooses compression values that we've found work well for podcasters, and result in podcasts that sound great to your listners, but don't waste the free space on their devices. If you're mixing with Cast, you're all done here. Take a break – you've earned it!

If You're Mixing On Your Own

If you're compressing your audio on your own, your first step might be to take a look at the compression used on some of the podcasts you listen to by opening the files in an audio tool.

We have a few suggestions, though:

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