Audio Separation Callbacks

When vocal separation tasks are completed, the system will send results to your provided callback URL via POST request

When you submit a task to the Vocal Separation API, you can use the callBackUrl parameter to set a callback URL. When the task is completed, the system will automatically push the results to your specified address.

Callback Mechanism Overview

The callback mechanism eliminates the need to poll the API for task status. The system will proactively push task completion results to your server.

Callback Timing

The system will send callback notifications in the following situations:

• Vocal separation task completed successfully
• Vocal separation task failed
• Errors occurred during task processing

Callback Method

• HTTP Method: POST
• Content Type: application/json
• Timeout Setting: 15 seconds

Callback Request Format

When the task is completed, the system will send different format callback data based on the separation type you selected:

separate_vocal Type Success Callback

{
  "code": 200,
  "data": {
    "task_id": "3e63b4cc88d52611159371f6af5571e7",
    "vocal_removal_info": {
      "instrumental_url": "https://file.aiquickdraw.com/s/d92a13bf-c6f4-4ade-bb47-f69738435528_Instrumental.mp3",
      "origin_url": "",
      "vocal_url": "https://file.aiquickdraw.com/s/3d7021c9-fa8b-4eda-91d1-3b9297ddb172_Vocals.mp3"
    }
  },
  "msg": "vocal Removal generated successfully."
}

Status Code Description

code · integer · required

Callback status code indicating task processing result:

Status Code	Description
200	Success - Vocal separation completed
400	Bad Request - Parameter error, unsupported audio file format, etc.
451	Download Failed - Unable to download source audio file
500	Server Error - Please try again later

msg · string · required

Status message providing detailed status description

data.task_id · string · required

Task ID, consistent with the taskId returned when you submitted the task

data.vocal_removal_info · object

Vocal separation result information, returned on success

separate_vocal Type Field Description

data.vocal_removal_info.origin_url · string

Original mixed audio file URL

data.vocal_removal_info.instrumental_url · string

Instrumental-only audio file URL (vocals removed)

data.vocal_removal_info.vocal_url · string

Vocals-only audio file URL (instrumental removed)

split_stem Type Field Description

data.vocal_removal_info.origin_url · string

Original mixed audio file URL

data.vocal_removal_info.vocal_url · string

Vocals-only audio file URL

data.vocal_removal_info.backing_vocals_url · string

Backing vocals audio file URL

data.vocal_removal_info.drums_url · string

Drums audio file URL

data.vocal_removal_info.bass_url · string

Bass audio file URL

data.vocal_removal_info.guitar_url · string

Guitar audio file URL

data.vocal_removal_info.keyboard_url · string

Keyboard audio file URL

data.vocal_removal_info.percussion_url · string

Percussion audio file URL

data.vocal_removal_info.strings_url · string

Strings audio file URL

data.vocal_removal_info.synth_url · string

Synthesizer audio file URL

data.vocal_removal_info.fx_url · string

Effects audio file URL

data.vocal_removal_info.brass_url · string

Brass audio file URL

data.vocal_removal_info.woodwinds_url · string

Woodwinds audio file URL

Callback Reception Examples

Here are example codes for receiving callbacks in popular programming languages:

Node.js

const express = require('express');
const app = express();

app.use(express.json());

app.post('/vocal-separation-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received vocal separation callback:', {
    taskId: data.task_id,
    status: code,
    message: msg
  });
  
  if (code === 200) {
    // Task completed successfully
    console.log('Vocal separation completed');
    const vocalInfo = data.vocal_removal_info;
    
    if (vocalInfo) {
      console.log('Separation results:');
      console.log(`  Original audio: ${vocalInfo.origin_url}`);
      
      // Handle different separation types
      if (vocalInfo.instrumental_url) {
        // separate_vocal type
        console.log(`  Instrumental only: ${vocalInfo.instrumental_url}`);
        console.log(`  Vocals only: ${vocalInfo.vocal_url}`);
      } else {
        // split_stem type
        console.log(`  Vocals: ${vocalInfo.vocal_url}`);
        console.log(`  Backing vocals: ${vocalInfo.backing_vocals_url}`);
        console.log(`  Drums: ${vocalInfo.drums_url}`);
        console.log(`  Bass: ${vocalInfo.bass_url}`);
        console.log(`  Guitar: ${vocalInfo.guitar_url}`);
        console.log(`  Keyboard: ${vocalInfo.keyboard_url}`);
        console.log(`  Percussion: ${vocalInfo.percussion_url}`);
        console.log(`  Strings: ${vocalInfo.strings_url}`);
        console.log(`  Synthesizer: ${vocalInfo.synth_url}`);
        console.log(`  Effects: ${vocalInfo.fx_url}`);
        console.log(`  Brass: ${vocalInfo.brass_url}`);
        console.log(`  Woodwinds: ${vocalInfo.woodwinds_url}`);
      }
      
      // Download separated audio files
      const https = require('https');
      const fs = require('fs');
      
      const downloadFile = (url, filename) => {
        if (!url) return;
        
        const file = fs.createWriteStream(filename);
        https.get(url, (response) => {
          response.pipe(file);
          file.on('finish', () => {
            file.close();
            console.log(`Saved: ${filename}`);
          });
        }).on('error', (err) => {
          console.error(`Download failed ${filename}:`, err.message);
        });
      };
      
      // Download all available audio files
      Object.keys(vocalInfo).forEach(key => {
        if (vocalInfo[key] && key.endsWith('_url')) {
          const filename = `${data.task_id}_${key.replace('_url', '')}.mp3`;
          downloadFile(vocalInfo[key], filename);
        }
      });
    }
    
  } else {
    // Task failed
    console.log('Vocal separation failed:', msg);
    
    // Handle failure cases...
    if (code === 400) {
      console.log('Parameter error or unsupported audio format');
    } else if (code === 451) {
      console.log('Source audio file download failed');
    } else if (code === 500) {
      console.log('Server internal error');
    }
  }
  
  // Return 200 status code to confirm callback received
  res.status(200).json({ status: 'received' });
});

app.listen(3000, () => {
  console.log('Callback server running on port 3000');
});

Best Practices

Callback URL Configuration Recommendations

1. Use HTTPS: Ensure your callback URL uses HTTPS protocol for secure data transmission
2. Verify Source: Verify the legitimacy of the request source in callback processing
3. Idempotent Processing: The same taskId may receive multiple callbacks, ensure processing logic is idempotent
4. Quick Response: Callback processing should return a 200 status code as quickly as possible to avoid timeout
5. Asynchronous Processing: Complex business logic should be processed asynchronously to avoid blocking callback response
6. File Management: Separated audio file download and processing should be done in asynchronous tasks
7. Type Detection: Determine separation type based on returned fields and apply corresponding processing logic

Important Reminders

• Callback URL must be a publicly accessible address
• Server must respond within 15 seconds, otherwise it will be considered a timeout
• If 3 consecutive retries fail, the system will stop sending callbacks
• Please ensure the stability of callback processing logic to avoid callback failures due to exceptions
• Generated audio file URLs may have time limits, recommend downloading and saving promptly
• split_stem mode produces more files, pay attention to storage space management
• Ensure source audio file contains corresponding musical components for optimal separation results
• Different separation types have different callback structures, requiring appropriate processing logic

Troubleshooting

If you do not receive callback notifications, please check the following:

Network Connection Issues

• Confirm that the callback URL is accessible from the public network
• Check firewall settings to ensure inbound requests are not blocked
• Verify that domain name resolution is correct

Server Response Issues

• Ensure the server returns HTTP 200 status code within 15 seconds
• Check server logs for error messages
• Verify that the interface path and HTTP method are correct

Content Format Issues

• Confirm that the received POST request body is in JSON format
• Check that Content-Type is application/json
• Verify that JSON parsing is correct
• Ensure proper handling of different separation type data structures

Audio Processing Issues

• Confirm that separated audio file URLs are accessible
• Check audio download permissions and network connections
• Verify audio save paths and permissions
• Note how source audio file quality affects separation results
• Confirm source audio file format is supported
• split_stem mode requires checking more audio files

Alternative Solution

If you cannot use the callback mechanism, you can also use polling:

Poll Query Results

Use the get vocal separation details endpoint to regularly query task status. We recommend querying every 30 seconds.