> What format would you recommend? It would need to be well-supported by podcast players.
HE-AAC. Support for HE-AAC and HE-AAC v2 has been universal on modern media platforms and operating systems for well over a decade.¹
• All versions of Android support HE-AAC v2 playback²
- Google also added encoders in Android 4.1 (2012)
• iOS introduced support for HE-AAC v2 playback in iOS 4 (released 2010)
• macOS introduced support for HE-AAC v2 playback with iTunes 9.2 (released 2010)
• I'm not sure when Windows added support, but it was available in Windows 8
• All open source players support HE-AAC v2 playback via FAAD2
FWIW, I distributed a reasonably-popular podcast (1.2M downloads over its lifetime) using HE-AAC v2 several years ago, and never received a complaint, or found a player it didn't work on.
¹ I read the other comments recommending Opus before responding, and although Opus is very nice, it's not as efficient or as ubiquitous as HE-AAC.
FAAD2 is in non-free repositories; for open source, it presents a problem with distribution outside of freeworld.
Neither Opus nor mp3 have this problem. So to maximize compatibility, mp3 is still the best choice, due to the attitude to Opus and other free codecs that Apple has.
> FAAD2 is in non-free repositories; for open source, it presents a problem with distribution outside of freeworld.
I may be misspeaking about FAAD2, but I've never run into an open-source player (like VLC) or library (like ffmpeg) which hasn't supported at least HE-AAC decode for a decade or more. If that's wrong, I'd love to be corrected in the most detailed way possible.
FFmpeg is exactly the kind of application, that in non-pruned configuration (i.e. with codecs like AAC) distributions cannot distribute binaries legally in some countries.
E.g. for Fedora, it is in rpmfusion repository and not in the distribution proper. Other distributions have similar arrangement for license-os-ok-but-patents-are-problem situation. These servers are outside US (or other countries that recognize software patents), and for the US users, the issue of obtaining the license is up to them.
The situation is so bad, that Fedora stopped shipping support for hardware acceleration of patented codecs (i.e. not complete codecs, but support to use the implementation in hardware, for example in your GPU), because they could be sued for contributory infringement.
Also note, that binaries for VLC or ffmpeg for Windows or Mac are similarly distributed from non-US servers, so basically the same situation as rpmfusion.
Note how AAC has effectively the same efficiency as Opus? HE-AAC and HE-AACv2 are notably better in comparison, and are usable at lower bitrates than AAC.
In cases where "the opposite is very well established", they're talking about AAC-LC. Citations that show otherwise are welcome! In any case, HE-AAC's universality is really beaten only by MP3 (which it trounces).
HE-AAC. Support for HE-AAC and HE-AAC v2 has been universal on modern media platforms and operating systems for well over a decade.¹
FWIW, I distributed a reasonably-popular podcast (1.2M downloads over its lifetime) using HE-AAC v2 several years ago, and never received a complaint, or found a player it didn't work on.¹ I read the other comments recommending Opus before responding, and although Opus is very nice, it's not as efficient or as ubiquitous as HE-AAC.
² https://developer.android.com/guide/topics/media/media-forma...