3G2 to SPX Converter

Strip audio from 3G2 video recordings as SPX online

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Settings

Set the overall output Speex audio bitrate. Designed for human speech encoding, Speex reaches transparency at ultra-low bitrate with a maximum bitrate of 44 kbps.
Set the number of audio channels. This setting is most useful when downmixing channels (e.g., from 5.1 to stereo).
Set the sample rate of the audio. Music with a full spectrum (20 Hz — 20 kHz) requires values not lower than 44.1 kHz to achieve transparency. More info can be found on the wiki.

3g2

3G2 (3GPP2 file format) is a multimedia container developed by the 3rd Generation Partnership Project 2 for use on CDMA2000 mobile networks. Built on the ISO base media file format (MPEG-4 Part 12), it stores video encoded with H.263 or MPEG-4 Visual alongside audio in AMR, EVRC, or AAC codecs. The specification was first published in December 2003 to provide a standardized way for CDMA-based phones and networks to handle multimedia messaging and video playback. 3G2 files are engineered for extremely low-bandwidth conditions, achieving playable video quality at bit rates as low as 30-60 kbps. This makes the format especially efficient for mobile video capture on devices with limited processing power and storage. The container supports multiple tracks, timed text for subtitles, and embedded metadata. One significant benefit is near-universal compatibility with CDMA handsets from the mid-2000s era, ensuring reliable playback across a wide range of mobile devices. Though newer formats like MP4 have superseded 3G2 for most purposes, it remains useful for working with legacy mobile content and for situations where minimal file size is the primary concern.
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spx

Speex is an open-source audio codec purpose-built for speech compression, developed by Jean-Marc Valin under the Xiph.Org Foundation. First released in October 2002, it targets voice-over-IP, conferencing, and any scenario where spoken word needs to travel efficiently over a network. SPX files wrap Speex-encoded audio inside an Ogg container, pairing the codec's speech optimization with Ogg's streaming capabilities. Three sampling rates are supported — narrowband at 8 kHz, wideband at 16 kHz, and ultra-wideband at 32 kHz — along with variable bitrate encoding that adapts in real time to speech complexity. A standout advantage is its patent-free, BSD-licensed nature, which allowed developers to embed it freely in both commercial and open-source products. Speex also bundles acoustic echo cancellation, noise suppression, and automatic gain control, features that rival codecs typically delegate to external libraries. Although its creators officially recommend Opus) as a successor since 2012, Speex remains deployed in legacy VoIP systems, archived recordings, and embedded devices where its lightweight decoder footprint is still valued.
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Fast Processing

3G2 to SPX conversion happens on cloud servers at speed. Extract audio from video and download the SPX result in moments.

No Installation

The converter runs entirely in your web browser. No plugins, no apps, no downloads — just open convertio.tools and start converting immediately.

Simple Workflow

Three steps — upload, choose format, download. No technical knowledge needed. The clean interface makes conversion straightforward for everyone.

How to convert 3G2 to SPX

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose spx or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your spx file right afterwards

About formats

3G2 (3GPP2 file format) is a multimedia container developed by the 3rd Generation Partnership Project 2 for use on CDMA2000 mobile networks. Built on the ISO base media file format (MPEG-4 Part 12), it stores video encoded with H.263 or MPEG-4 Visual alongside audio in AMR, EVRC, or AAC codecs. The specification was first published in December 2003 to provide a standardized way for CDMA-based phones and networks to handle multimedia messaging and video playback. 3G2 files are engineered for extremely low-bandwidth conditions, achieving playable video quality at bit rates as low as 30-60 kbps. This makes the format especially efficient for mobile video capture on devices with limited processing power and storage. The container supports multiple tracks, timed text for subtitles, and embedded metadata. One significant benefit is near-universal compatibility with CDMA handsets from the mid-2000s era, ensuring reliable playback across a wide range of mobile devices. Though newer formats like MP4 have superseded 3G2 for most purposes, it remains useful for working with legacy mobile content and for situations where minimal file size is the primary concern.
Initial release: December 2003
Speex is an open-source audio codec purpose-built for speech compression, developed by Jean-Marc Valin under the Xiph.Org Foundation. First released in October 2002, it targets voice-over-IP, conferencing, and any scenario where spoken word needs to travel efficiently over a network. SPX files wrap Speex-encoded audio inside an Ogg container, pairing the codec's speech optimization with Ogg's streaming capabilities. Three sampling rates are supported — narrowband at 8 kHz, wideband at 16 kHz, and ultra-wideband at 32 kHz — along with variable bitrate encoding that adapts in real time to speech complexity. A standout advantage is its patent-free, BSD-licensed nature, which allowed developers to embed it freely in both commercial and open-source products. Speex also bundles acoustic echo cancellation, noise suppression, and automatic gain control, features that rival codecs typically delegate to external libraries. Although its creators officially recommend Opus) as a successor since 2012, Speex remains deployed in legacy VoIP systems, archived recordings, and embedded devices where its lightweight decoder footprint is still valued.
Initial release: October 15, 2002

Frequently Asked Questions

What is the benefit of converting 3G2 to SPX?

Speex excels at compressing speech efficiently. Extracting SPX from 3G2 is useful for voice recordings, IVR systems, and bandwidth-limited communication.

What software plays SPX?

You can play SPX with VLC, Audacity, and Speex-compatible VoIP and communication software.

Can I convert 3G2 to SPX on my phone?

Yes — convertio.tools works in any mobile browser. Upload your 3G2, select SPX, and download the result directly to your phone or tablet.

Do I need to install anything?

The converter is completely web-based. No software, no plugins — just open convertio.tools in any modern browser and convert 3G2 to SPX directly.

Is the conversion private and secure?

Uploaded files are deleted immediately after conversion, and completed SPX downloads are removed from our servers within 24 hours for full privacy.

Will the entire audio track be extracted?

Yes, the converter extracts the entire audio stream from start to finish. The SPX contains everything heard in the original 3G2 recording.