trimAudio

The trimAudio function allows you to trim audio files with precision, supporting multiple segments and various output formats. This is useful for removing silence, extracting specific parts of recordings, or compiling multiple segments into a single audio file.

Syntax

async function trimAudio(options: TrimAudioOptions): Promise<string>

Parameters

The function accepts a single object with the following properties:

Property	Type	Required	Default	Description
fileUri	string	Yes	-	Path to the audio file to trim
startTimeMs	number	No*	-	Start time in milliseconds (for single segment mode)
endTimeMs	number	No*	-	End time in milliseconds (for single segment mode)
mode	'keep' | 'remove'	No	'keep'	Whether to keep or remove the specified ranges
ranges	Array<{startTimeMs: number, endTimeMs: number}>	No*	-	Array of time ranges (for multi-segment mode)
outputFormat	OutputFormatOptions	No	See below	Output format configuration

* Either startTimeMs/endTimeMs pair or ranges must be provided

OutputFormatOptions

Property	Type	Required	Default	Description
format	'wav' | 'mp3' | 'aac' | 'opus'	No	'wav'	Output audio format
bitrate	number	No	-	Bitrate for compressed formats (in kbps)
quality	'low' | 'medium' | 'high'	No	'medium'	Quality preset for compressed formats

Default value for outputFormat is { format: 'wav' }.

Return Value

The function returns a Promise that resolves to a string containing the URI of the trimmed audio file.

Examples

Basic Trimming

import { trimAudio } from '@siteed/expo-audio-studio';

async function trimAudioSegment() {
  try {
    // Trim audio from 1 second to 5 seconds
    const trimmedAudioUri = await trimAudio({
      fileUri: 'path/to/recording.wav',
      startTimeMs: 1000,
      endTimeMs: 5000,
      outputFormat: { format: 'wav' }
    });
    
    console.log(`Trimmed audio saved to: ${trimmedAudioUri}`);
    return trimmedAudioUri;
  } catch (error) {
    console.error('Error trimming audio:', error);
    throw error;
  }
}

Multiple Segments

import { trimAudio } from '@siteed/expo-audio-studio';

async function extractMultipleSegments() {
  try {
    // Extract and combine two segments from the audio file
    const compiledAudioUri = await trimAudio({
      fileUri: 'path/to/recording.wav',
      mode: 'keep',
      ranges: [
        { startTimeMs: 1000, endTimeMs: 5000 },
        { startTimeMs: 10000, endTimeMs: 15000 }
      ],
      outputFormat: { format: 'mp3', quality: 'high' }
    });
    
    console.log(`Compiled audio saved to: ${compiledAudioUri}`);
    return compiledAudioUri;
  } catch (error) {
    console.error('Error extracting audio segments:', error);
    throw error;
  }
}

Removing Segments

import { trimAudio } from '@siteed/expo-audio-studio';

async function removeSilenceOrNoise() {
  try {
    // Remove specific segments (e.g., silence or noise) from the audio
    const cleanedAudioUri = await trimAudio({
      fileUri: 'path/to/recording.wav',
      mode: 'remove',
      ranges: [
        { startTimeMs: 2000, endTimeMs: 3000 },  // Remove silence
        { startTimeMs: 7000, endTimeMs: 8500 }   // Remove noise
      ],
      outputFormat: { format: 'aac', bitrate: 128 }
    });
    
    console.log(`Cleaned audio saved to: ${cleanedAudioUri}`);
    return cleanedAudioUri;
  } catch (error) {
    console.error('Error removing audio segments:', error);
    throw error;
  }
}

Use Cases

• Content Editing: Extract the most important parts of a recording
• Silence Removal: Remove silent segments from recordings
• Compilation: Combine multiple segments into a single audio file
• Noise Removal: Remove sections containing unwanted noise
• Audio Clipping: Create short clips from longer recordings

Performance Considerations

• Processing large audio files may take longer, especially when converting formats
• When possible, use the same output format as the input to avoid transcoding overhead
• For multiple small segments, it's more efficient to process them in a single operation using the ranges parameter rather than making multiple calls
• The function is optimized to minimize memory usage even for large files