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12 January 20266 min

The Future of Sentence Mining: One-Click Audio Slicing from Desktop

ankisentence miningaudio slicingautomationffmpeg

If you've been sentence mining for Anki, you know the pain: pause the video, start system audio recording, play the sentence, stop recording, save the file, add it to Anki. There's a better way—and it only works on desktop.

The Manual Audio Recording Problem

Traditional sentence mining workflows require you to manually record audio for each card:

  1. Find a good sentence: Pause your video at the right moment
  2. Start Audacity (or similar): Open your recording software
  3. Record system audio: Play the sentence, capture the audio
  4. Trim and export: Cut silence from the beginning/end, save as MP3
  5. Add to Anki: Create the card, upload the audio file

For one card, this takes 2-3 minutes. If you mine 20 sentences per episode, that's an hour of pure busywork. And that's assuming you don't make mistakes—like forgetting to start recording or cutting the audio at the wrong timestamp.

Why Browser Extensions Can't Solve This

Some browser extensions attempt to automate sentence mining. But they face fundamental limitations:

  • No Direct File Access: Browsers can't access video files on your computer. Extensions only work with streaming platforms like Netflix or YouTube.
  • Recording vs. Slicing: Browser extensions must record audio in real-time (like you do manually). They can't directly extract audio from the source file.
  • Platform Restrictions: Netflix and other platforms actively block extensions from accessing raw video streams. This means audio extraction breaks frequently.

Desktop apps don't have these limitations. They can directly read your video file and extract audio at precise timestamps—no recording, no platform restrictions.

How FFmpeg Makes Audio Slicing Instant

FFmpeg is a powerful open-source tool that reads and manipulates video files. When integrated into a desktop app, it enables true one-click audio slicing:

  1. You click a subtitle line: The app knows the start and end timestamp (e.g., 00:12:34.500 → 00:12:38.200)
  2. FFmpeg extracts the audio segment: The app runs a command to slice audio from your video file at those exact timestamps
  3. Audio file is generated instantly: No recording, no trimming. The clip is pixel-perfect to the subtitle timing.
  4. Added to your Anki card automatically: The app embeds the audio in the flashcard. Done.

This entire process takes milliseconds. You're not waiting for playback or recording—the audio is extracted directly from the file.

How to Audio Slice Local Video for Anki Without Manual Recording

Here's what the workflow looks like with a desktop app like SubSmith (coming soon to the roadmap):

  1. Open your video file: Any local MKV, MP4, or AVI works
  2. Generate transcript: SubSmith creates timestamped subtitles automatically
  3. Watch and click: As you watch, click any subtitle line you want to mine
  4. Export to Anki: The app generates a flashcard with the sentence text + audio clip pre-attached

No Audacity. No manual recording. No trimming silence. Just click, export, done.

Fastest Way to Export Sentences from MP4 to Anki (One-Click)

Let's compare the time investment for creating 20 Anki cards:

Manual workflow (traditional method):

  • Find sentence, record audio, trim, export, create card
  • 3 minutes per card × 20 cards = 60 minutes

Automated workflow (desktop app with FFmpeg slicing):

  • Click subtitle line, export to Anki
  • 10 seconds per card × 20 cards = ~3 minutes

That's a 20x speed improvement. And because the audio is sliced programmatically, there are no human errors—no accidentally cropped audio, no background noise from your room, no volume inconsistencies.

Automatic Anki Card Creator for Offline Video Files

The full vision for sentence mining automation includes:

  • Batch Export: Select 10 subtitle lines, export all 10 as Anki cards in one click
  • Screenshot Integration: Optionally include a screenshot of the scene for visual context
  • Dictionary Pre-Fill: Auto-populate the "back" of the card with a dictionary definition of unknown words
  • Direct Anki Sync: No CSV export—cards appear directly in your Anki deck via AnkiConnect

This is the endgame for immersion learners: watch content, click interesting sentences, and your Anki deck populates automatically. No busywork, just pure comprehensible input.

How to Mine Sentences from Podcasts with Timestamps

This workflow isn't just for video. Audio-only content (podcasts, audiobooks) benefits even more:

  1. Import MP3 or M4A file: SubSmith transcribes the audio and generates timestamped text
  2. Review transcript: Read through the text, mark interesting sentences
  3. Export with audio: Each sentence gets its audio clip sliced from the original podcast file

Why this matters: Podcasts rarely have transcripts. Even when they do, they lack timestamps. Automated transcription + audio slicing turns any podcast into a mineable resource.

Best Subtitle Tool for 100+ Hour Immersion Challenges (No Crashes)

If you're doing a serious immersion challenge—100 hours, 500 hours, 1000 hours—you need tools that don't crash or slow down. Here's why desktop apps are superior:

  • No Memory Leaks: Browser extensions accumulate memory over long sessions. Desktop apps manage resources efficiently.
  • Background Processing: Queue up 10 episodes to transcribe overnight. Browser extensions can't do this.
  • Batch Operations: Export 100 sentences at once without freezing your browser.

When you're committing to hundreds of hours of immersion, the last thing you want is your tools breaking halfway through.

When Is This Coming to SubSmith?

SubSmith currently focuses on local transcription and subtitle generation. You can try it with a free trial to experience:

  • Local transcription powered by Whisper AI
  • Subtitle generation and export (SRT files)
  • Support for 99+ languages

On the roadmap:

  • One-click audio slicing with FFmpeg
  • Direct Anki integration via AnkiConnect
  • Batch sentence mining (export multiple cards at once)
  • Cloud transcription for faster processing
  • Cloud TTS for pronunciation practice
  • History and insights tracking

These automation features will eliminate all the busywork from sentence mining workflows.

The Bottom Line: Automate or Burn Out

Sentence mining is the most effective way to build vocabulary from context. But if the workflow is painful, you won't stick with it. Automation removes the friction.

Manual audio recording might work for your first 50 cards. But when you're aiming for 5,000+ mined sentences (the typical path to fluency), you need tools that scale. Desktop apps with FFmpeg integration are the only way to make this sustainable.

Ready to try it? Download SubSmith and start with a free trial to experience local transcription. As roadmap features launch, you'll have the fastest sentence mining workflow ever built.

FAQ

  • Can I sentence mine from VLC or MPV player automatically? Not directly. VLC supports Whisper integration through plugins for subtitle generation, but neither VLC nor MPV have built-in sentence mining features. SubSmith plans to combine the player + mining workflow in one app (on the roadmap).
  • Do I need to install FFmpeg separately? No—SubSmith includes FFmpeg bundled with the app. Everything works out of the box.
  • Will this work with Netflix or YouTube? SubSmith focuses on local files (downloaded media). For streaming platforms, browser extensions like Language Reactor remain the best option.
  • Can I export to other SRS apps besides Anki? CSV export is planned for the roadmap, which will be compatible with any SRS tool. Direct integration with Anki is prioritized first due to its large user base.