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Subtitle Composer
What it is
Subtitle Composer is a free, open-source subtitle editor for Linux, with tools for straightforward edits and more involved subtitle work. It opens and saves text formats such as SRT, MicroDVD, SSA/ASS, MPlayer, TMPlayer, and YouTube captions, and can open or use OCR on several graphics subtitle formats. You can preview subtitles in an integrated video player or on an audio waveform, choose an audio stream, and demux subtitle streams from video files. Editing tools include synchronization, time shifting and scaling, frame-rate conversion, joining and splitting files, side-by-side translations, text styling, spell checking, and timing-error detection. It supports speech recognition from audio or video using PocketSphinx, as well as subtitle translation; version 0.8.0 release notes list DeepL and Google Cloud translation engines. Linux installation options include Discover or another AppStream store, distribution package managers, Flathub, an x86_64 AppImage, and source downloads. Version 0.8.2 requires FFmpeg 5.1.5 or later. The product page lists the GPL-2.0+ license.
For and against
For
- Opens and saves several text subtitle formats.
- Previews subtitles in video or on an audio waveform.
- Includes synchronization and timing-error detection tools.
- Supports speech recognition using PocketSphinx.
- Available through multiple Linux installation options.
Against
- Requires FFmpeg version 5.1.5 or later.
- Listed platform is Linux.
The verdict
Subtitle Composer brings subtitle editing, preview, translation, and speech-recognition tools into a Linux application. Check the FFmpeg requirement before installing.
Who it suits
Subtitle Composer suits Linux users who need to edit, synchronize, or translate subtitles in a range of text formats. Its speech-recognition support may also suit users working from audio or video files.
Plans and prices
Subtitle Composer
No paid plans or usage limits stated
Read 3 Oct 2026 · apps.kde.org
On the record
- Auto-captioning
- Yesapps.kde.org · read 20 Sep 2026
- Download
- The product page lists Linux installation through Discover or another AppStream store, distribution package managers, and Flathub, plus an x86_64 AppImage and source downloads.apps.kde.org · read 3 Oct 2026
- Editing tools
- Features include synchronization, time shifting and scaling, frame-rate conversion, joining and splitting files, side-by-side translations, text styling, spell checking, and timing-error detection.apps.kde.org · read 3 Oct 2026
- Legal entity
- KDE says its legal and financial matters are represented by KDE e.V., a registered non-profit in Germany.kde.org · read 3 Oct 2026
- License
- The product page lists the license as GPL-2.0+.apps.kde.org · read 3 Oct 2026
- Maker
- KDE describes itself as an international community developing free, open-source software and says it has done so since 1996.kde.org · read 3 Oct 2026
- Runtime requirement
- The 0.8.2 release announcement says Subtitle Composer requires FFmpeg version 5.1.5 or later.subtitlecomposer.kde.org · read 3 Oct 2026
- Scripting
- The feature list describes scripting through languages supported by Kross; the 0.8.0 release notes say Kross was replaced with QJSEngine and Python and Ruby support were removed.apps.kde.org · read 3 Oct 2026
- Security and privacy
- KDE's software privacy policy says KDE software generally does not transmit information from end-user devices except after an explicit user action, and says any telemetry is opt-in and disabled by default where present.kde.org · read 3 Oct 2026
- Speaker labels
- Yesapps.kde.org · read 20 Sep 2026
- Speech recognition
- The application supports speech recognition from audio or video files using PocketSphinx.apps.kde.org · read 3 Oct 2026
- SRT export
- Yesapps.kde.org · read 20 Sep 2026
- Subtitle formats
- It opens and saves text formats including SRT, MicroDVD, SSA/ASS, MPlayer, TMPlayer, and YouTube captions, and can open or OCR several graphics subtitle formats.apps.kde.org · read 3 Oct 2026
- Support
- The product page links to KDE's Discuss help forum and provides a bug-report link.apps.kde.org · read 3 Oct 2026
- Subtitle translation
- Yesapps.kde.org · read 20 Sep 2026
- Translation engines
- The 0.8.0 release notes say DeepL and Google Cloud translation engines were added.apps.kde.org · read 3 Oct 2026
- Video and audio
- It can demux subtitle streams from video files and preview subtitles in an integrated video player or on an audio waveform, with audio stream selection.apps.kde.org · read 3 Oct 2026
- VTT export
- Yesapps.kde.org · read 20 Sep 2026
