Function convertAudioWithFFmpeg

apps/sim/lib/audio/extractor.ts:117–182

* Convert audio/video using FFmpeg

(
  inputBuffer: Buffer,
  mimeType: string,
  options: AudioExtractionOptions
)

 * Convert audio/video using FFmpeg
 */
async function convertAudioWithFFmpeg(
  inputBuffer: Buffer,
  mimeType: string,
  options: AudioExtractionOptions
): Promise<AudioExtractionResult> {
  // Create temporary files
  const tempDir = os.tmpdir()
  const inputExt = getExtensionFromMimeType(mimeType)
  const outputFormat = options.outputFormat || 'mp3'
  const inputFile = path.join(tempDir, `ffmpeg-input-${Date.now()}.${inputExt}`)
  const outputFile = path.join(tempDir, `ffmpeg-output-${Date.now()}.${outputFormat}`)

  try {
    // Write input buffer to temporary file
    await fs.writeFile(inputFile, inputBuffer)

    // Get metadata for duration
    let duration = 0
    try {
      const metadata = await getAudioMetadataFromFile(inputFile)
      duration = metadata.duration || 0
    } catch (error) {
      // Metadata extraction failed, continue without duration
      logger.warn('Failed to extract metadata:', error)
    }

    // Convert using FFmpeg
    await new Promise<void>((resolve, reject) => {
      let command = ffmpeg(inputFile).toFormat(outputFormat).audioCodec(getAudioCodec(outputFormat))

      // Apply audio options
      if (options.channels) {
        command = command.audioChannels(options.channels)
      }
      if (options.sampleRate) {
        command = command.audioFrequency(options.sampleRate)
      }
      if (options.bitrate) {
        command = command.audioBitrate(options.bitrate)
      }

      command
        .on('end', () => resolve())
        .on('error', (err) => reject(new Error(`FFmpeg error: ${err.message}`)))
        .save(outputFile)
    })

    // Read output file
    const outputBuffer = await fs.readFile(outputFile)

    return {
      buffer: outputBuffer,
      format: outputFormat,
      duration,
      size: outputBuffer.length,
    }
  } finally {
    // Clean up temporary files