SPX - Speex

FLV MP3 Converter converts any media files to SPX. The software supports batch conversion and, is full compatible with 32-bit and 64-bit editions of Vista and Windows 7.

Speex is a patent-free audio compression format designed for speech and also a free software speech codec that may be used on VoIP applications and podcasts.[5] It is based on the CELP speech coding algorithm.[6] Speex claims to be free of any patent restrictions and is licensed under the revised (3-clause) BSD license. It may be used with the Ogg container format or directly transmitted over UDP/RTP.

Unlike many other speech codecs, Speex is not targeted at cellular telephony but rather at Voice over IP (VoIP) and file-based compression. The design goals have been to make a codec that would be optimized for high quality speech and low bit rate. To achieve this the codec uses multiple bit rates, and supports ultra-wideband (32 kHz sampling rate), wideband (16 kHz sampling rate) and narrowband (telephone quality, 8 kHz sampling rate). Since Speex was designed for Voice over IP (VoIP) instead of cell phone use, the codec must be robust to lost packets, but not to corrupted ones. All this led to the choice of Code Excited Linear Prediction (CELP) as the encoding technique to use for Speex.[6] One of the main reasons is that CELP has long proven that it could do the job and scale well to both low bit rates (as evidenced by DoD CELP @ 4.8 kbit/s) and high bit rates (as with G.728 @ 16 kbit/s). The main characteristics can be summarized as follows:

• Free software/open-source, patent and royalty-free.
• Integration of narrowband and wideband in the same bit-stream.
• Wide range of bit rates available (from 2 kbit/s to 44 kbit/s).
• Dynamic bit rate switching and Variable bit-rate (VBR).
• Voice Activity Detection (VAD, integrated with VBR) (not working from version 1.2).
• Variable complexity.
• Ultra-wideband mode at 32 kHz (up to 48 kHz).
• Intensity stereo encoding option.

The Speex codec is designed to be very flexible and support a wide range of speech quality and bit-rate. Support for very good quality speech also means that Speex can encode wideband speech (16 kHz sampling rate) in addition to narrowband speech (telephone quality, 8 kHz sampling rate).

Designing for VoIP instead of mobile phones means that Speex is robust to lost packets, but not to corrupted ones. This is based on the assumption that in VoIP, packets either arrive unaltered or don't arrive at all. Because Speex is targeted at a wide range of devices, it has modest complexity (variable) and memory footprint.

All the design goals led to the choice of CELP as the encoding technique. One of the main reasons is that CELP has long proved that it could work reliably and scale well to both low bit-rates (e.g. DoD CELP @ 4.8 kbps) and high bit-rates (e.g. G.728 @ 16 kbps).

Convert Files to SPX (Speex):

• Convert 3GP to SPX
• Convert AAC to SPX
• Convert AC3 to SPX
• Convert ADX to SPX
• Convert AIFF to SPX
• Convert AMR to SPX
• Convert APE to SPX
• Convert ASF to SPX
• Convert AU to SPX
• Convert AVI to SPX
• Convert CAF to SPX
• Convert DTS to SPX
• Convert DVD to SPX
• Convert DVR-MS to SPX
• Convert FLAC to SPX
• Convert FLV to SPX
• Convert M4A to SPX
• Convert M4B to SPX
• Convert M4V to SPX
• Convert MKA to SPX
• Convert MKV to SPX
• Convert MLP to SPX
• Convert MOV to SPX
• Convert MP2 to SPX
• Convert MP3 to SPX
• Convert MP4 to SPX
• Convert MPA to SPX
• Convert MPC to SPX
• Convert MPG to SPX
• Convert OGG to SPX
• Convert QCP to SPX
• Convert RA to SPX
• Convert RM to SPX
• Convert SHN to SPX
• Convert THD to SPX
• Convert TS to SPX
• Convert TTA to SPX
• Convert VOB to SPX
• Convert VOC to SPX
• Convert WAV to SPX
• Convert WMA to SPX
• Convert WMV to SPX
• Convert WV to SPX