M2TS to SPH Converter

Extract M2TS Blu-ray audio as SPHERE speech data online

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Blu-ray to Speech Data

Extract dialogue from M2TS video and package it as NIST SPHERE — ready for speech recognition training and linguistic corpus building.

Research-Grade Quality

M2TS Blu-ray files deliver high-quality audio. SPH output preserves that quality in a format designed for serious speech research work.

Secure Processing

M2TS uploads are deleted after conversion. SPH output files are removed within 24 hours — your research materials remain private.

How to convert M2TS 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

M2TS (MPEG-2 Transport Stream) is a container format used primarily for multiplexing audio, video, and other data on Blu-ray Disc media. The format is specified as part of the Blu-ray Disc Audio-Video (BDAV) standard developed by the Blu-ray Disc Association, with commercial Blu-ray products launching in 2006. M2TS files wrap content in MPEG-2 transport stream packets with an additional 4-byte timestamp header prepended to each 188-byte packet, resulting in 192-byte packets that enable more precise timing and error recovery during optical disc playback. This extended packet structure helps maintain synchronization when dealing with the variable read speeds inherent to disc-based media. M2TS supports the major Blu-ray video codecs including H.264/AVC, MPEG-2, and VC-1, alongside audio formats such as Dolby TrueHD, DTS-HD Master Audio, and LPCM for lossless surround sound. The container is also used by AVCHD camcorders for recording high-definition footage, making it common in both consumer disc playback and video production workflows. M2TS files preserve chapter markers, subtitle streams, and interactive menu data within the transport stream. Reliable synchronization mechanisms and support for high-quality codecs make M2TS well-suited for archiving high-definition content where preserving full source quality is essential.
Initial release: 2006
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 convert M2TS to SPH?

SPH is the NIST standard for speech research audio. Extracting M2TS dialogue into SPH format builds datasets from Blu-ray video content.

Does SPH capture HD audio well?

SPH stores PCM data without compression. High-quality M2TS audio translates well — speech content reaches your research tools with full clarity.

What frameworks use SPH?

Kaldi, HTK, Praat, and NIST speech evaluation tools all work with SPH natively. It is the standard interchange format for speech research.

Can I extract specific audio?

The full audio track from M2TS is extracted. For specific dialogue segments, trim your M2TS source before conversion for targeted results.

How are multiple channels handled?

SPH supports multi-channel data, but speech corpora typically use mono. M2TS surround audio is mixed down based on the output configuration.