Master Your Audiobook for Google Play Books

What Are Google Play Books' Audio Requirements?

Google Play Books does not publish specific RMS loudness, true peak, or noise floor targets. Google's stated requirements focus on format and bitrate: MP3 at 128 kbps or higher for mono (256 kbps or higher for stereo) with constant bit rate (CBR) preferred.[1] Google Play Books also accepts FLAC, WAV, and M4A/AAC, the widest format acceptance of any major audiobook platform.[1] This flexibility means authors have more options for file delivery, but the absence of loudness specs does not mean loudness does not matter. Listeners still expect consistent, comfortable volume levels.

How Does ChapterPass Handle Google Play Books Requirements?

ChapterPass produces mono MP3 files at 192 kbps CBR, which exceeds Google Play Books' minimum of 128 kbps. The output sample rate is 44.1 kHz, matching Google's requirement. Because ChapterPass masters to ACX specifications , the strictest in the audiobook industry. The output inherently satisfies Google Play Books' less restrictive requirements. ChapterPass sets RMS loudness between -23 and -18 dBFS, limits true peak below -3 dBFS, and manages noise floor below -60 dBFS.[2] Even though Google does not publish these targets, mastering to ACX standards ensures professional-quality audio that sounds consistent on every listening device.

What Makes Google Play Books Different From ACX?

Google Play Books differs from ACX in several ways that matter for audiobook producers. Format flexibility is the biggest difference: Google accepts four formats (MP3, FLAC, WAV, M4A/AAC) while ACX accepts only MP3.[2] Google's minimum MP3 bitrate is 128 kbps for mono[1], compared to ACX's 192 kbps minimum.[2] Google Play Books accepts both mono and stereo files, unlike ACX which requires mono only.[2]

Google Play Books does not publish specific loudness, true peak, or noise floor targets. ACX, by contrast, enforces precise measurements: -23 to -18 dBFS RMS, below -3 dBFS true peak, and below -60 dBFS noise floor.[2] The absence of strict loudness specs on Google's platform does not mean loudness is irrelevant. Professional audiobook listeners expect consistent volume levels, and mastering to industry-standard levels ensures a quality listening experience.

Google Play Books also supports its Auto-narrated audiobooks programme, which lets publishers create AI-narrated versions of their books. This programme uses Google's text-to-speech technology and does not require uploaded audio files, a fundamentally different approach from traditional narration and mastering.

The total audiobook duration limit on Google Play Books is 100 hours, with a minimum of 5 minutes.[1] ACX does not state a total duration limit but requires each file to be a separate chapter. Google's generous limits accommodate virtually any audiobook length.

Can You Submit the Same Files to Both ACX and Google Play Books?

Yes. ACX requirements are stricter than Google Play Books' stated requirements in every category. ChapterPass output (192 kbps CBR MP3, 44.1 kHz, mono, -23 to -18 dBFS RMS, below -3 dBFS true peak, below -60 dBFS noise floor) exceeds all Google Play Books minimums. The same files work for both platforms without any changes. Authors distributing through multiple platforms, including Findaway Voices and Authors Republic, can use a single set of ChapterPass-mastered files everywhere.

Sources

1. Google Play Books Partner Help
2. ACX Audio Submission Requirements