Convert 3G2 to MP3 - extract audio
3G2 files came off CDMA phones - Verizon, Sprint, KDDI. Audio is EVRC or QCELP (speech codecs) or, on later devices, AAC (see Audio codecs explained for where each codec fits today). Wave decodes all of them and re-encodes to a portable 192 kbps MP3.
What actually changes
CDMA-era phone audio was almost always a speech codec - EVRC (Enhanced Variable Rate Codec) or QCELP (Qualcomm Code Excited Linear Prediction) - because CDMA networks were speech-first infrastructure. Both codecs run at 8-13 kbps mono, sampled at 8 kHz. Wave decodes them through the ffmpeg-wasm engine's evrc and qcelp decoders and re-encodes to MP3 at 192 kbps VBR through libmp3lame. Because the source is speech-bandwidth-limited, the MP3 output preserves every audible sample but doesn't exceed the source's inherent bandwidth ceiling.
Later 3G2 files (post-2005 CDMA phones with music-playback features) added AMR-NB, AMR-WB, and AAC audio. AMR sources treat the same way (decode then re-encode); AAC sources decode through ffmpeg's AAC decoder and re-encode. All paths land at a stereo MP3 at 192 kbps regardless of source bitrate or sample rate.
The most common use case for 3G2 audio extraction is preserving voicemails, MMS audio-video attachments, and short talk clips from the CDMA-phone era. A significant share of the personal-archive content on old backup drives from 2004-2010 is 3G2 files with EVRC audio - short clips of children's first words, family gatherings, spontaneous street music, that sort of thing. Extracting to a portable MP3 makes those files play in every modern podcast app, music player, and archival tool.
Because CDMA speech codecs are heavily bandwidth-limited (they were designed to fit inside 8 kbps voice channels), the resulting MP3 will sound bandwidth-limited too. That's baked into the source and can't be fixed post-hoc. If your source is a QCELP recording, the MP3 will be an MP3 of that QCELP recording - the source, not the target, sets the ceiling.
Three steps.
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Step 1
Drop the .3g2 file onto the card.
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Step 2
Pick MP3 as the output format.
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Step 3
Convert. Save the MP3.
Answers, specifically.
QCELP - is that decoded?
Yes. QCELP was Qualcomm's CDMA speech codec, used on nearly every CDMA phone from 1998 through the mid-2000s. ffmpeg-wasm bundles the decoder.
EVRC support?
Yes. EVRC is the successor to QCELP with better speech quality at the same bandwidth. Wave decodes it and re-encodes to MP3.
Voicemails saved as .3g2?
Yes, if you can get the raw file. Some CDMA voicemail archive tools (from Verizon, Sprint) exported voicemails as .3g2 with QCELP or AMR audio. Wave extracts audio directly.
File size?
A one-minute 3G2 with QCELP audio is typically 60-100 KB - tiny. The MP3 output at 192 kbps is much larger (about 1.4 MB per minute) because the format itself is more verbose, but the source bandwidth is unchanged.
Will the MP3 sound "phone-quality"?
Yes. CDMA speech codecs cap the source at telephone-audio bandwidth (200 Hz to 3.4 kHz). The MP3 preserves that; playing it on studio speakers will sound the same as playing the original through the phone speaker.
What if my 3G2 has AAC music audio?
Wave decodes AAC and re-encodes to MP3 the same as any other AAC source. Later 3G2 files (2005+) with AAC music tracks land at genuine music quality after the MP3 conversion.
iPhone or Android phone videos - are those 3G2?
No. iPhone videos are .mov (H.264 + AAC); Android videos are .mp4 (H.264 + AAC). 3G2 is specifically the CDMA-phone-era format. Use the MP4-to-MP3 or MOV-to-MP3 pages for modern phone videos.