Subtitle Composer is an open source text-based subtitle editor that supports basic and advanced editing operations.

Features
<ul><li>Open/Save Text Subtitle Formats - SubRip/SRT, MicroDVD, SSA/ASS, MPlayer, TMPlayer and YouTube captions</li><li>Open/OCR Graphics Subtitle Formats - VobSub (.idx/.sub/.rar), BluRay/PGS (*.sup), formats supported by ffmpeg (DVD/Vob, DVB, XSUB, HDMV-PGS)</li><li>Demux Graphics/Text Subtitle Stream from video file - SRT, SSA/ASS, MOV text, MicroDVD, DVD/Vob, DVB, XSUB, HDMV-PGS</li><li>Speech recognition from audio/video file using PocketSphinx</li><li>Smart language/text encoding** detection</li><li>Live preview of subtitles in integrated video player w/ audio stream selection</li><li>Preview/editing of subtitles on graphical audio waveform w/ audio stream selection</li><li>Sync by dragging several anchors/graftpoints and stretching timeline</li><li>Time shifting and scaling, lines duration re-calculation, framerate conversion, etc.</li><li>Joining and splitting of subtitle files</li><li>Side by side subtitle translations</li><li>Text styles (italic, bold, underline, stroke, color)</li><li>Spell checking</li><li>Detection of timing errors in subtitles</li><li>Scripting (JavaScript, Python, Ruby and other languages supported by Kross).</li></ul>