Feat/volume slider

[shivashanker123]

Description

This PR introduces a dedicated Audio Volume Slider Control Component to the video editor's Audio & Speed configuration panel. It gives users granular control over their video's output audio levels, supporting complete attenuation up to high-gain digital boosting.

✨ Key Features & Implementations:

1. Granular Frontend Input Widget: Added a customized input slider that ranges from 0% (fully muted) to 200% (boosted amplification) with a precision step multiplier.
2. FFmpeg Core Integration: Seamlessly hooked the component value state into the client-side export generation pipeline. Adjustments correctly update the centralized EditRecipe state parameters and dynamically compile the exact -af volume=X audio filter string combinations inside the FFmpeg execution arguments layer.
3. Smart UI Context Management: To preserve layout stability and avoid sudden Cumulative Layout Shifts (CLS), the slider safely switches to a disabled state (reduced to opacity: 50% with suspended pointer events) when the keepAudio toggle is disabled or when an audio-less format like GIF is selected.
4. Automated Validation: Updated the underlying unit testing framework suite inside ffmpeg.test.ts to fully validate the integrity of the newly introduced audio filter parsing blocks.

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Related Issue

Closes #1081

Type of Contribution

• Bug fix
• New feature
• Enhancement / Optimization
• Refactor
• GSSoC contribution

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Participant Info

• GitHub username: shivashanker123
• Contribution level (Beginner/Intermediate/Advanced): Advanced

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Screen Recording

🎬 Click to View Feature Walkthrough & Verification Video

🔊 Volume Slider (0-200%) & Conditional State Validation Flow

Screen.Recording.2026-05-24.193505.mp4

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Checklist

• I have read the contribution guidelines
• My changes follow the project structure
• I have tested my changes in Chrome, Firefox, and Safari
• bun run lint passes (no ESLint errors)
• bunx tsc --noEmit passes (no TypeScript errors)
• New interactive elements have aria-label / accessible names
• No console.log statements left in
• This PR is related to a valid issue
• Screen recording attached above

[vercel]

@shivashanker123 is attempting to deploy a commit to the magic-peach1's projects Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

👋 Thanks for your PR, @shivashanker123!

Welcome to Reframe — a browser-based video editor built for everyone 🎬

🟠 GSSoC'26 PR detected — thanks for contributing under GirlScript Summer of Code 2026!

What happens next

1. 🤖 Automated checks — build & TypeScript typecheck will run automatically
2. ✅ Vercel preview — a preview deployment will be created (requires maintainer authorization for fork PRs)
3. 👀 Code review — a maintainer will review your changes
4. 🚀 Merge — once approved, your PR will be merged!

Quick checklist

• PR title follows Conventional Commits (e.g. feat: add dark mode)
• Linked the issue this PR closes (e.g. Closes #123)
• Tested the changes locally (bun run dev)
• Build passes (bun run build)

Useful links

• 📖 CONTRIBUTING.md
• 🐛 Open Issues
• ⭐ Star the repo to support the project!

Happy coding! 🎉

[github-actions]

⚠️ PR Format Issues — @shivashanker123

Please fix the following before your PR can be reviewed:

• ⚠️ Use a conventional PR title. Examples:
  • feat: add dark mode support
  • fix: resolve aria label missing on slider
  • docs: add deployment guide to README

Push new commits after fixing — this comment will update automatically.

📖 CONTRIBUTING.md