Tutorials/video-generator/README.md

# Video Generator Voiceover

Small helper scripts for creating timed tutorial voiceovers from `.srt` files and replacing a video's original audio with the generated voiceover.

## Files

- `video-generator/scripts/combine_video_audio.py` — one-step final video generation, or two-step audio replacement
- `video-generator/scripts/make_voiceover_macos.py` — creates timed WAV/optional MP3 voiceover on macOS
- `video-generator/scripts/make_voiceover_windows.py` — creates timed WAV/optional MP3 voiceover on Windows
- `video-generator/subtitles/` — optional place to keep SRT files
- `video-generator/output/` — optional place to save generated audio/video files

## Install

### Windows

```powershell
winget install Gyan.FFmpeg
```

Install Python from `python.org` or Microsoft Store, then reopen PowerShell and check:

```powershell
ffmpeg -version
python --version
```

### macOS

```bash
brew install ffmpeg
```

Python is already available on most Macs. If needed, install it from `python.org`.

## One-step flow: create final video from SRT

Use this when you already have the tutorial video and the `.srt` narration file. It creates temporary voiceover audio, removes the video's original audio, exports the final MP4, and deletes temporary voice parts automatically.

### Windows

```powershell
python video-generator/scripts/combine_video_audio.py `
  --video "video-generator/input/your_video.mp4" `
  --srt "video-generator/subtitles/your_subtitles.srt" `
  --voice "Microsoft David Desktop" `
  --rate 0 `
  --output "video-generator/output/final_video.mp4"
```

### macOS

```bash
python video-generator/scripts/combine_video_audio.py \
  --video "video-generator/input/your_video.mp4" \
  --srt "video-generator/subtitles/your_subtitles.srt" \
  --voice "Daniel" \
  --rate 185 \
  --output "video-generator/output/final_video.mp4"
```

`--voice` and `--rate` are optional. If omitted, the script uses the default voice and speed for your operating system.

## Two-step flow: create voiceover

Use this when you want to review or edit the generated audio before combining it with the video.

### Windows

```powershell
python video-generator/scripts/make_voiceover_windows.py `
  --srt "video-generator/subtitles/your_subtitles.srt" `
  --voice "Microsoft David Desktop" `
  --rate 0 `
  --wav "video-generator/output/voiceover.wav" `
  --mp3 "video-generator/output/voiceover.mp3"
```

### macOS

```bash
python video-generator/scripts/make_voiceover_macos.py \
  --srt "video-generator/subtitles/your_subtitles.srt" \
  --voice "Daniel" \
  --rate 185 \
  --wav "video-generator/output/voiceover.wav" \
  --mp3 "video-generator/output/voiceover.mp3"
```

`--mp3` is optional. Use WAV when combining with video.

## Two-step flow: combine video + audio

This removes the original video audio and uses the generated voiceover.

### Windows

```powershell
python video-generator/scripts/combine_video_audio.py `
  --video "video-generator/input/your_video.mp4" `
  --audio "video-generator/output/voiceover.wav" `
  --output "video-generator/output/final_video.mp4"
```

### macOS

```bash
python video-generator/scripts/combine_video_audio.py \
  --video "video-generator/input/your_video.mp4" \
  --audio "video-generator/output/voiceover.wav" \
  --output "video-generator/output/final_video.mp4"
```

Use absolute paths if files are outside this folder.

## Voice and speed options

### Windows voice list

```powershell
Add-Type -AssemblyName System.Speech
$synth = New-Object System.Speech.Synthesis.SpeechSynthesizer
$synth.GetInstalledVoices() | ForEach-Object { $_.VoiceInfo.Name }
```

Good tutorial voices: `Microsoft David Desktop`, `Microsoft Mark` if available.

Windows speed uses `-10` to `10`:

```powershell
python video-generator/scripts/combine_video_audio.py `
  --video "video-generator/input/your_video.mp4" `
  --srt "video-generator/subtitles/your_subtitles.srt" `
  --output "video-generator/output/final_video.mp4" `
  --voice "Microsoft David Desktop" `
  --rate 2
```

To add voices: `Settings > Time & language > Speech > Manage voices > Add voices`.

### macOS voice list

```bash
say -v '?'
```

Good tutorial voices: `Daniel`, `Reed (English (US))`, `Eddy (English (UK))`.

Speed example:

```bash
python video-generator/scripts/combine_video_audio.py \
  --video "video-generator/input/your_video.mp4" \
  --srt "video-generator/subtitles/your_subtitles.srt" \
  --output "video-generator/output/final_video.mp4" \
  --voice "Daniel" \
  --rate 190
```

## Optional advanced options

These options are not needed for normal usage.

- `--audio-output "output/voiceover.wav"` — saves a copy of the generated voiceover WAV in one-step mode.
- `--keep-temp` — keeps temporary voice parts for debugging. By default, temporary files are deleted.
- `--volume 1.2` — changes voiceover volume. Default is `1.0`.
- `--silence-padding 0.15` — adds a small pause after each caption if the SRT time slot has enough space. Default is `0.0`.
- `--sample-rate 48000` — changes generated audio sample rate. Default is `44100`.
- `--channels 1` — changes generated audio channels. Use `1` for mono or `2` for stereo. Default is `2`.
- `--reencode-video` — re-encodes video with H.264 if the copied video output has compatibility issues.

Example:

```bash
python video-generator/scripts/combine_video_audio.py \
  --video "video-generator/input/your_video.mp4" \
  --srt "video-generator/subtitles/your_subtitles.srt" \
  --output "video-generator/output/final_video.mp4" \
  --audio-output "video-generator/output/voiceover.wav" \
  --volume 1.2 \
  --silence-padding 0.15 \
  --sample-rate 48000 \
  --channels 2
```

## Notes

If a caption has too much text for its time slot, the script keeps the SRT timing and trims the speech. Fix that by increasing the subtitle duration, shortening the sentence, or increasing speed.