Fluen AI Subtitle Generator vs SmartSub

Fluen AI Subtitle Generator turns uploaded audio and video into timed subtitles, with an editor for refining captions and exports for subtitle files or captioned video. Inputs include MP4, MOV, MKV, AVI, MP3, WAV, M4A and FLAC. Editing tools include timeline adjustments, speaker labels, filler-word removal and custom glossaries; detected speakers can be renamed or reassigned. Fluen translates captions into more than 50 languages with context-aware formatting and language-specific re-segmentation. Export formats include SRT, WebVTT, TTML, SBV, ITT, EBU STL, SSA, plain text and burned-in MP4. Batch processing, shared project workspaces, a REST API, outbound webhooks and Zapier connections to more than 9,000 apps are also listed. The free plan allows three files of up to 90 minutes each and does not require a card, but exporting requires a paid plan. Free translations are limited to three languages per file and show only the first 15 minutes. Premium costs $259 a year; Team costs $499 a year. Media retention is 30 days for Free, 90 days for Premium and 180 days for Team.

SmartSub is an open-source desktop app for transcription, subtitle translation, proofreading, AI dubbing and video subtitle rendering. It runs on Windows, macOS and Linux, and is free with no local usage limits. For local processing, its maker says models process files on the user's computer, so those files do not leave the device. Transcription options include whisper.cpp, faster-whisper, FunASR, Qwen3-ASR and FireRedASR. Translation includes 20 services, including built-in free translation and integrations such as DeepSeek, Gemini and Ollama. The proofreading workspace offers video-synced editing, undo and redo, search and replace, and AI proofreading. SmartSub can generate speech from subtitle lines, align audio to the timeline and clone voices with ZipVoice, Volcengine or ElevenLabs. It can burn subtitles into video or package soft subtitles, preview styles and include dubbed audio. It also downloads videos from links using yt-dlp and lux, supporting more than 1,800 sites. Cloud transcription uploads audio to the configured provider endpoint; the README advises against using it for sensitive content.