With AAC, chapter points are listed throughout the file, making it harder to support chapter points if streaming a podcast. With an MP3, chapter points are listed at the front of the file, allowing podcast apps who support them to be able to use them as soon as the file starts loading.Dynamic content insertion (used, mainly, for ads) typically don’t accept AAC format files.It’s unlikely you’ll use this, but worth knowing. Amazon Alexa’s News Briefing service also requires MP3 files.For this reason alone, you probably still need to be producing MP3 versions of your podcast. Spotify and Deezer require MP3 format files, and do not import AAC files at all.Lower bitrate means lower filesize, and that means it’s cheaper to host, cheaper and faster to download, quicker to stream, and takes up less space on your listener’s phone.For most people, an AAC file at 64kbps sounds about the same as an MP3 file at 128kbps. AAC offers much better audio quality at the same bitrate - or, and probably more usefully, great quality at much lower bitrate.In late 2019, it was calculated that 4.3% of podcasts have chosen to use AAC format but since Anchor automatically produces podcasts in AAC format (and has many different podcasts hosted on it), 39% of new podcasts use AAC. Virtually every podcast host will let you upload an AAC file. However, if a device wants to play back video - like your mobile phone does, for example - it’ll already have AAC decoders paid-for, so in practice, almost everything these days has AAC support. There are still patents on AAC decoders, so device manufacturers need to pay money to the patent owners. HE-AAC v2 was standardised in 2006, and is v2 of the “High Efficiency” version of the codec. However, in most cases, “AAC” really means “HE-AAC v2” for the purposes of this article, at least at lower bitrates.

m4a so some people call them “M4A files”, but the audio codec they use is AAC, and we’ll use that name in this article.ĪAC stands for “Advanced Audio Coding”, and it was initially released in 1997. Variable bitrate causes quite a few problems for podcasts, and the general advice is not to use variable bitrate (sometimes known as VBR) for podcasting. You can produce MP3 files in two bitrate formats - constant bitrate or variable bitrate. MP3 files are playable on almost anything, and the patents for MP3 expired in 2017, so it’s free to build an MP3 player or encoder.

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Mp3 variable to fixed bitrate converter