3G2 to SPH Converter

Strip audio from 3G2 video recordings as SPH online

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Private and Secure

Your uploads are processed on encrypted servers and deleted right after conversion. Output files are purged within 24 hours for complete privacy.

Fast Processing

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

Batch Processing

Upload and convert multiple files simultaneously. Our cloud infrastructure processes them in parallel, saving you time on larger jobs.

How to convert 3G2 to SPH

1

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

2

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

3

Let the file convert and you can download your sph 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 Though newer formats like MP4 have superseded 3G2 for most purposes, it remains useful for working with legacy mobile content and for situations where minimal file size is the primary concern.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
SPH is the file extension for audio stored in the NIST SPHERE (SPeech HEader REsources) format, a standard created by the U.S. National Institute of Standards and Technology around 1990. Built for speech research, SPH files carry a 1024-byte ASCII header packed with metadata — database identifiers, channel counts, sample rates, byte ordering, and compression type — making every recording self-describing. The underlying audio is typically 16-bit linear PCM sampled at 16 kHz, though other configurations are permitted. Researchers at NIST, DARPA, and universities worldwide rely on SPH for distributing speech corpora such as TIMIT, Switchboard, and the LDC collections that underpin modern automatic speech recognition systems. A key advantage is that the human-readable header lets scripts parse recording metadata without binary decoding. The format's strict standardization also eliminates ambiguity when sharing datasets across institutions and platforms. Because SPH files store uncompressed PCM, they preserve full audio fidelity — critical when training acoustic models where even small artifacts can skew results.
Initial release: 1990

Frequently Asked Questions

Why should I convert 3G2 to SPH?

SPH is used in particular professional or legacy systems. Moving 3G2 audio to SPH ensures compatibility with applications that depend on this format.

How can I open SPH files?

Open SPH using NIST speech tools, HTK, and SoX for acoustic research playback.

Can I batch convert multiple 3G2 files?

You can upload and convert multiple 3G2 files to SPH at the same time. Batch processing runs on our servers so your device stays free.

Do I need to install anything?

No downloads or plugins needed. The 3G2 to SPH converter runs entirely in your web browser — just visit convertio.tools and start converting.

Can I convert 3G2 to SPH on my phone?

The tool works on smartphones and tablets. Open convertio.tools in your mobile browser, upload the 3G2, choose SPH, and download when done.

Does converting 3G2 to SPH lose quality?

With proper settings, the converted SPH retains excellent clarity. Lossless formats preserve full quality, while lossy ones trade minimal detail for size.