GSM 6.10 WAV Won’t Play in Gmail — Here’s Why and the Fix
You have a .wav voicemail that Gmail refuses to play, and a codec check shows it’s GSM 6.10 (WAV format code 49). This is one of the formats Chrome has no decoder for at all. Here’s what that means and how to play it.
Play any voicemail attachment directly in Gmail
Gmail Audio Player decodes µ-law, A-law, GSM, AMR and other telephony formats inside your browser. No downloads. First 10 plays free.
What GSM 6.10 is
GSM 6.10 (also called GSM Full Rate) is a low-bitrate speech codec designed for telephone networks. PBX and older VoIP systems use it to keep voicemail files small. Inside a WAV container it’s identified by the format tag 49 (0x31) in the file header.
That small size is great for phone systems and terrible for browsers: it’s a specialised telephony codec with no place in the web media stack, so no mainstream browser ships a decoder for it.
How to confirm it
The fix: decode GSM inline in Gmail
Gmail Audio Player bundles a WebAssembly decoder that handles GSM 6.10 directly in your browser. It detects the attachment, decodes the GSM audio to standard PCM locally, and plays it inside the email — no conversion, no download, no uploads.
Install it once and every GSM voicemail that used to fail will simply play, with a scrubber, adjustable speed, and optional transcription on paid plans.
Frequently asked questions
How do I know my WAV is GSM 6.10?
Open the file in VLC (Tools → Media Information → Codec) and look for "GSM" or format code 49 in the WAV header. If VLC plays it but Gmail doesn't, it's almost certainly a telephony codec like GSM.
Why does Chrome have no GSM decoder?
GSM 6.10 is a 1990s telephony compression format with no consumer media use. Browser vendors only ship codecs used by streaming and the web, so GSM support was never added — and won't be.
Can I convert GSM WAV to a normal WAV?
Yes, with a tool like VLC, Audacity or ffmpeg — but that means downloading, converting, and re-opening every file. Gmail Audio Player skips all of that by decoding it inline in your browser.
Is the file corrupted?
No. A GSM WAV that fails in Gmail is a valid file. The issue is purely that your browser lacks the decoder, not that the data is damaged.
Related fixes
Play your voicemail attachments inside Gmail.
Fix playback in under two minutes. First 10 plays free, no account required.
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