What Is an SRT File, How to Create One, and How to Use It for AI Sound Design

What Is an SRT File?

SRT (SubRip Text) is a plain-text format that stores your video's subtitles with timestamps. Each entry has three parts: an index number, a start → end timestamp, and the subtitle text.

1
00:00:03,200 --> 00:00:06,800
I'm exploring the historic peninsula of Istanbul today.

2
00:00:07,100 --> 00:00:11,400
Standing in front of Hagia Sophia — an incredible feeling.

This format tells an AI when each scene happens and what it's about — making it the most critical input for automated sound design.

How to Create an SRT File

Method 1: Download from YouTube Studio (Easiest)

If you've already uploaded your video to YouTube, auto-generated captions may already be available.

1. Go to YouTube Studio → Subtitles in the left menu
2. Find your video and click it
3. Select the generated language → click the three-dot menu → Download
4. Choose .srt format

If no captions exist yet, click Add language on the same screen and trigger YouTube's Whisper-based auto-captioning. It takes a few minutes.

Method 2: Local Transcription with Whisper

If your video isn't published yet, or privacy matters, run OpenAI Whisper locally:

pip install openai-whisper
whisper video.mp4 --output_format srt --language en

This saves video.srt in the same folder. No GPU required; processing time is roughly 1/3 the video's length with the large model.

Method 3: Online Tools

Descript, Otter.ai, or Kapwing let you upload a video and export an SRT. Watch for free-tier limits — longer videos usually require a paid plan.

Method 4: Write It Manually

Open any text editor and follow the format above. Timestamps use millisecond precision (HH:MM:SS,mmm). Save the file as UTF-8 with the .srt extension.

What Makes a Good SRT File?

SRT quality directly affects your AI sound design results. Key things to check:

• Short segments: Ideally 1–2 sentences per entry. Long blocks blur scene boundaries.
• Accurate timestamps: Silent pauses and scene transitions should be reflected in the timings.
• UTF-8 encoding: Especially important for non-Latin characters. Wrong encoding corrupts the file.
• Blank lines between entries: Required by the format — missing blank lines cause parsing errors.

Using Your SRT File in SceneFX AI

Once you have an SRT file, using SceneFX AI is straightforward:

1. Go to scenefxai.app and create an account (20 free credits, no card required)
2. Click New Project → Upload SRT
3. Drag in your SRT file. Optionally add your audio or video file for better silence detection
4. Claude AI runs scene analysis (~30–60 seconds)
5. Review the suggested sound effects and music → click Generate
6. Build your mix and download — delivered at YouTube-standard −14 LUFS

Does It Work Without an SRT?

Yes. SceneFX AI also accepts raw audio or video files. In that case, the platform runs its own transcription (Whisper) first to generate an SRT, then proceeds with sound design. But if you already have a clean SRT, uploading it directly is faster and usually more accurate.

Conclusion

Creating an SRT file is easier than most creators expect — for an already-published video, it's just a few clicks in YouTube Studio. Hand that file to SceneFX AI, and the model understands each scene well enough to generate scene-specific, royalty-free sound effects and music automatically.

Try it free: scenefxai.app/sign-up →

This post is in English. A Turkish version is also available.

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