So you’ve written your podcast. You’ve recorded it. You’ve edited it and added music. You’re all set. Everything has come together well.
And then along comes a problem. It’s time to save the audio file. So you hit the save button and you get a long, long list of file formats.
What file format should you choose?
The choice can be overwhelming at first glance. After all audacity provides more than twelve different file formats. It seems like everyone who is producing a sound program produces their own format. And instead of becoming obsolete each of the formats seems to hold on for ever after.
Of course, in an article of this size discussing all the formats possible isn’t possible. So in this article I’m going to discuss nine different podcast file formats available to you.
1. Moving Pictures Expert Group – Standard 1 or 2 Audio Layer III (MPG or MP3). This is the de-facto standard for audio files — podcast or otherwise. Usable on most players it has only one problem. It is a lossy format meaning that it reduces file size by discarding frequencies outside of the given range. As a result, the quality of the recording can vary from tinny telephone up to near-CD quality.
2. Microsoft Waveform Audio File Format (WAV). This format is raw and uncompressed — meaning it takes up a lot of space but gives a high quality, lossless sound. Occasionally, these are used for podcasting but frankly they are ill-suited to a talk show format where lost frequencies will improve the overall sound rather than reduce the quality.
3. Audio Interchange File Format (AIFF). This is Apple’s version of the WAV file. While it is used for professional sound recording it is both specialized and massive meaning that it, like the WAV is ill-suited for podcasts.
4. Windows Media Audio (WMA). This is a proprietary format which can be either lossless or lossy. It was developed to overcome deficiencies in the MP3 format. However, because it is proprietary it varies in acceptance. Use of this format for your podcast may mean some potential customers cannot play your audio files.
5. Ogg Vobis. This is actually an Open Source media container. While the fact that it is open source encourages its adoption, it has not in fact caught on. The majority of your audience probably doesn’t know what it is or how to use it.
6. Compact Disk Audio (CDA or PCM). This is the format used by Compact Discs. CDA format is actually a pointer to a Pulse-Code Modulation (PCM) file. These files are often used as the basis for WAV and other files. However, they aren’t used very often for podcasts due to their size.
7. Advanced Audio Coding (AAC). This was originally designed to be the replacement for the MP3 format. Although it is loss (like the MP3) it is generally achieves lower files sizes than MP3 for the same quality. It is the default format for Sony, Apple and several smartphone manufacturers. Unfortunately, it doesn’t have the same adoption rate as MP3.
8. Real Audio (RA or RAM). This was originally a streaming media format. While it is used in the PC world, it is frequently not supported in other industries.
9. Audio (AU). Developed by Sun Microsystems for the NexT computer, it is a lossy file format. In practice it is not used a great deal as most podcast players consider it as a proprietary format.