shuffle and buffle

Description:
A web-based tool for applying buffer shuffle effects to audio files.
Provides real-time visualization of the resulting audio and options to download the processed track.

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Features

• Shuffle audio at byte-level blocks (buffer shuffle)
• Adjustable block size and shuffle intensity
• Optional start and end offsets to shuffle only part of the track
• Real-time audio visualizer
• Custom play/pause controls
• Download the processed WAV file

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User Interface

Inputs

• File Upload – Select an audio file.
• Block Size (bytes) – Range slider (256–8192). Sets the size of each block used in shuffling.
• Shuffle Intensity (%) – Range slider (1–100). Controls how many blocks will be randomly swapped.
• Start Offset (%) – Range slider (0–50). Sets the start point of shuffling relative to the track length.
• End Offset (%) – Range slider (50–100). Sets the end point of shuffling relative to the track length.

Buttons

• Shuffle Buffer – Generates the shuffled audio buffer based on current settings.
• Play – Plays the shuffled audio.
• Pause – Stops the current playback.
• Download – Download the shuffled audio as a WAV file.

Visualizer

• Canvas – Displays the waveform of the audio in real-time during playback.

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How It Works

1. File Loading

   • WAV file is read using FileReader and decoded with AudioContext.decodeAudioData().

2. Buffer Shuffle Algorithm

   • The selected range (startOffset → endOffset) is divided into blocks of the chosen size.
   • Random swaps are applied according to the shuffle intensity.
   • The shuffled blocks are merged into a new audio buffer.

3. Playback

   • The shuffled buffer is played using an AudioBufferSourceNode.
   • Playback can be started/stopped using Play/Pause buttons.

4. Download

   • The buffer is converted to WAV format using DataView and Blob.
   • The download link points to the generated WAV file.

5. Visualization

   • An AnalyserNode provides time-domain data for drawing the waveform on the canvas.
   • The waveform updates in real-time during playback.

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Code Overview

Variables

• audioCtx – Web Audio API AudioContext
• analyser – AnalyserNode for waveform visualization
• sourceNode – Current AudioBufferSourceNode
• shuffledBuffer – Processed AudioBuffer with buffer shuffle applied
• dataArray – Uint8Array holding waveform data for visualization

Functions

• initAudioContext() – Initializes AudioContext and AnalyserNode.
• updateVisualization() – Draws waveform continuously on canvas.
• bufferToWav(buffer) – Converts an AudioBuffer to a WAV Blob.
• Event listeners handle shuffle, play, and pause functionality.

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Usage

1. Select an audio file using the file input.
2. Adjust block size, shuffle intensity, start offset, and end offset.
3. Click Shuffle Buffer to generate the shuffled track.
4. Use Play / Pause buttons to listen.
5. Click Download to save the shuffled WAV file.

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License

MIT License