File size: 2,652 Bytes
29ead2c d9879cf 29ead2c | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | import { exec } from 'child_process';
import { promisify } from 'util';
import { writeFile, readFile, unlink } from 'fs/promises';
import { join } from 'path';
import { randomBytes } from 'crypto';
const execAsync = promisify(exec);
/**
* Converts an audio buffer to MP3 using local FFmpeg if the file is OGG/OPUS.
* This ensures compatibility with OpenAI Whisper, which frequently rejects native WhatsApp OPUS files.
* Returns the original buffer if ffmpeg fails or isn't installed to attempt best-effort transcription.
*/
export async function convertToMp3IfNeeded(inputBuffer: Buffer, filename: string): Promise<{ buffer: Buffer; format: string }> {
// We only strictly convert OGG or OPUS files (which are typical for WhatsApp).
// If it's already an MP4/AAC or M4A, Whisper usually accepts it fine.
if (!filename.toLowerCase().endsWith('.ogg') && !filename.toLowerCase().endsWith('.opus') && !filename.toLowerCase().endsWith('.oga')) {
return { buffer: inputBuffer, format: filename.split('.').pop()! };
}
const tempId = randomBytes(8).toString('hex');
const inputPath = join('/tmp', `in_${tempId}_${filename}`);
const outputPath = join('/tmp', `out_${tempId}.mp3`);
try {
console.log(`[FFMPEG] Starting conversion for ${filename}...`);
// Write the inbound buffer to a temp file
await writeFile(inputPath, inputBuffer);
// Run FFmpeg to convert it to a standard 128k MP3
// -y overwrites without prompting
// -i specifies input file
// -vn disables video just in case
// -ar sets audio sample rate
// -ac sets channels to mono (perfect for voice)
// -b:a sets audio bitrate to 64k (sufficient for voice, saves bandwidth)
await execAsync(`ffmpeg -y -i "${inputPath}" -vn -ar 44100 -ac 1 -b:a 64k "${outputPath}"`);
// Read the converted file back into a buffer
const mp3Buffer = await readFile(outputPath);
console.log(`[FFMPEG] ✅ Successfully converted ${filename} to MP3.`);
return { buffer: mp3Buffer, format: 'mp3' };
} catch (err: unknown) {
console.error(`[FFMPEG] ⚠️ Conversion failed for ${filename}. Proceeding with original buffer. Error: ${(err instanceof Error ? (err instanceof Error ? err.message : String(err)) : String(err))}`);
// If FFMPEG isn't installed or fails, we return the original buffer
return { buffer: inputBuffer, format: filename.split('.').pop()! };
} finally {
// Cleanup temp files asynchronously
unlink(inputPath).catch(() => { });
unlink(outputPath).catch(() => { });
}
}
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