FLV to SPX Converter

FLV (Flash Video) is a container format originally developed by Macromedia and later maintained by Adobe Systems after the 2005 acquisition. The format gained support for standalone playback with Flash Player 7 in 2003 and quickly became the dominant video format on the web, powering platforms like YouTube, Hulu, and Vimeo during the late 2000s. FLV files typically contain video encoded with the Sorenson Spark or VP6 codec alongside MP3 or ADPCM audio, wrapped in a lightweight proprietary container optimized for streaming delivery. The major strength of FLV was its ability to deliver consistent video playback across different operating systems and browsers through the ubiquitous Flash Player plugin, solving the fragmentation problem that plagued web video at the time. FLV files begin with a compact header followed by tagged data packets, a structure that enables fast seeking and efficient progressive download. The container supports embedded metadata with cue points, enabling interactive features like chapter navigation and timed events. FLV transformed online video from an unreliable niche experience into a mainstream medium, fundamentally reshaping entertainment, education, and communication on the internet. Although HTML5 video and modern codecs have replaced Flash-based delivery, FLV files remain in countless archives and legacy systems.

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.