Overview

Auto Sub ReTimer is a local tool designed to automatically improve subtitle timing for .ass and .srt files.
It analyzes the audio track of your video to detect the exact start and end of spoken dialogue, then adjusts each subtitle line accordingly.
The process can also take into account scene changes, ensuring that subtitles appear and disappear in sync with visual cuts for a smoother viewing experience.

Key features:

• Automatic voice extraction from the video to isolate speech.
• Lead‑in/Lead‑out adjustment based on detected audio peaks.
• Scene change detection to align subtitles with visual transitions.
• Style preservation for .ass files original formatting and styles are kept.
• Local processing no internet connection required for timing adjustments after the first run.
• Optional GPU acceleration with NVIDIA CUDA for faster processing.

What exactly do the scripts do?
Do you want to change the values ​​to your preferences?
Read here

NVIDIA GPU Setup (Optional)

If you have an NVIDIA GPU and plan to use it:

• Open Auto Sub ReTimer GUI.bat with Notepad (right‑click > Edit).
• Locate the part of the file where it says cu118.
• Change cu118 to match the CUDA version supported by your GPU.

Tip: If you're unsure about your CUDA version, open a terminal (cmd) and type nvidia-smi to check it. You don’t necessarily have to use a recent CUDA version, you can also use an older one for better compatibility.
The important thing is that it is compatible with your NVIDIA card.

• Save and you're done!

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Preparing Your Files

• Put your video .mkv inside the Auto Sub ReTimer folder.

Example:

• Run Auto Sub ReTimer GUI.bat.

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Input Alignment Guidelines (Important)

THE LINE OF SPOKEN AUDIO IN THE SUB MUST BE WITHIN THE LINES AND NOT PARTIALLY OUTSIDE THE LINE (Audio Spectrum).
THERE MUST NOT BE THE START OF SPOKEN AUDIO THAT BEGINS BEFORE THE LINE, FOR EXAMPLE.
WHEN UPLOADING YOUR .ass OR .srt, MAKE SURE TO FOLLOW THE INSTRUCTIONS.
EVEN A QUICK SYNC THAT'S THE SAME FOR ALL LINES IS SUFFICIENT.
FOR EXAMPLE -0.050 OR -0.100.

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Does not meet the requirements

Meets the requirements

(It is not necessary for the initial timestamp to perfectly align with the beginning of the audio peak of the speech, the important thing is that the beginning of the speech is included, the rest will be handled by the program):

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Before and After Examples – Auto Sub ReTimer

Example 1 – Original Sub

Adjusted Sub with scene change:

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Example 2 – Original Sub

Adjusted Sub:

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Example 3 – Original Sub

Adjusted Sub with scene change:

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Whisper

Requirements

• Put your video .mkv and the folder Faster-Whisper-XXL inside the Auto Sub ReTimer folder.
• Run Auto Sub ReTimer GUI.bat and select "Whisper".

Improving whisper.srt

• Use Whisper ReTimer.
• You will have two options:
  • Use only a basic timing improvement.
  • Ensure it also respects scene changes.
• Once you have made your choice and the process is complete, you will find everything you need on the Desktop.

Keep in mind that the improvement with scene changes is not perfect, especially if used with the basic timing of Whisper.