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SPECIFICTION
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Subtitle Composer

apps.kde.org

Free plan Linux
Visit apps.kde.org
Spec score 7.9 #15 of 31 in Subtitle tools

What it is

Subtitle Composer is a free, open-source Linux application for basic and advanced text-based subtitle editing. It opens and saves SRT, MicroDVD, SSA/ASS, MPlayer, TMPlayer, and YouTube caption files, and can open or apply OCR to several graphics subtitle formats. Subtitle streams can be demuxed from video files, then previewed in an integrated video player or alongside an audio waveform with audio-stream selection. 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. Speech recognition works from audio or video through PocketSphinx. Translation support includes engines described in the 0.8.0 release notes, including DeepL and Google Cloud. Linux installation is available through Discover, package managers, Flathub, an x86_64 AppImage, and source downloads. Version 0.8.2 requires FFmpeg 5.1.5 or later.

Spec sheet

What it does
Subtitle Composer is an open-source, text-based subtitle editor for basic and advanced editing.Read 3 Oct 2026 · apps.kde.org
Free plan
YesRead 20 Sep 2026 · apps.kde.org
Support
The product page links to KDE's Discuss help forum and provides a bug-report link.Read 3 Oct 2026 · apps.kde.org
License
The product page lists the license as GPL-2.0+.Read 3 Oct 2026 · apps.kde.org
Maker
KDE describes itself as an international community developing free, open-source software and says it has done so since 1996.Read 3 Oct 2026 · kde.org
Auto-captioning
YesRead 20 Sep 2026 · apps.kde.org
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.Read 3 Oct 2026 · apps.kde.org
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.Read 3 Oct 2026 · apps.kde.org
Legal entity
KDE says its legal and financial matters are represented by KDE e.V., a registered non-profit in Germany.Read 3 Oct 2026 · kde.org
Runtime requirement
The 0.8.2 release announcement says Subtitle Composer requires FFmpeg version 5.1.5 or later.Read 3 Oct 2026 · subtitlecomposer.kde.org
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.Read 3 Oct 2026 · apps.kde.org
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.Read 3 Oct 2026 · kde.org
Speaker labels
YesRead 20 Sep 2026 · apps.kde.org
Speech recognition
The application supports speech recognition from audio or video files using PocketSphinx.Read 3 Oct 2026 · apps.kde.org
SRT export
YesRead 20 Sep 2026 · apps.kde.org
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.Read 3 Oct 2026 · apps.kde.org
Subtitle translation
YesRead 20 Sep 2026 · apps.kde.org
Translation engines
The 0.8.0 release notes say DeepL and Google Cloud translation engines were added.Read 3 Oct 2026 · apps.kde.org
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.Read 3 Oct 2026 · apps.kde.org
VTT export
YesRead 20 Sep 2026 · apps.kde.org

Plans and prices

Subtitle Composer Free Free No paid plans or usage limits stated Read 3 Oct 2026 · apps.kde.org

Every Subtitle Composer plan and price →

Strong points and limits

Strong points

  • Supports many subtitle text formats
  • Includes OCR for graphics subtitles
  • Provides waveform and video previews
  • Offers speech recognition with PocketSphinx
  • Distributed under GPL-2.0+

Limits

  • Runs on Linux
  • Requires FFmpeg 5.1.5 or later
  • Kross scripting support was replaced
  • Python and Ruby scripting support were removed

Who it suits

It suits Linux users editing, translating, synchronizing, or reviewing subtitles in text and graphics formats. It also fits workflows needing speech recognition, OCR, or waveform-based timing.

Verdict

Subtitle Composer covers a broad subtitle-editing workflow, from timing and styling to translation, recognition, and format conversion. Linux users should check the FFmpeg requirement and current scripting details before setup.

Where Specifiction places it

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