> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apimart.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# 分轨提取

>  - 从歌曲分离出指定轨（如人声）。
- 引用源音轨：`task_id` + `audio_index` 指定，无需记录任何额外 id
- 异步任务：提交返回 `task_id`，轮询 `GET /v1/music/tasks/:task_id` 获取结果 

> [!NOTE]
>
> **引用源音轨**：基于已有歌曲的操作无需记任何额外 id，只需传 `task_id`（产出源音轨那次任务的 task\_id）+ `audio_index`（结果 `data.result.music[]` 里第几首，1-based，默认 `1`）。

> [!NOTE]
>
> 本端点**无版本维度**：不要传 `version`，传了会被丢弃，也不影响计费。

```bash cURL theme={null}
curl -X POST https://api.apimart.ai/v1/music/generations/stems \
  -H 'Authorization: Bearer <token>' \
  -H 'Content-Type: application/json' \
  --data '{
    "model": "suno",
    "task_id": "task_01ABC",
    "audio_index": 1,
    "stem_type": "lead_vocal"
  }'
```

```python Python theme={null}
import requests

url = "https://api.apimart.ai/v1/music/generations/stems"

payload = {
    "model": "suno",
    "task_id": "task_01ABC",
    "audio_index": 1,
    "stem_type": "lead_vocal"
}

headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript JavaScript theme={null}
const url = "https://api.apimart.ai/v1/music/generations/stems";

const payload = {
  model: "suno",
  task_id: "task_01ABC",
  audio_index: 1,
  stem_type: "lead_vocal"
};

const headers = {
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
};

fetch(url, {
  method: "POST",
  headers: headers,
  body: JSON.stringify(payload)
})
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error('Error:', error));
```

```go Go theme={null}
package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    url := "https://api.apimart.ai/v1/music/generations/stems"

    payload := map[string]interface{}{
        "model": "suno",
        "task_id": "task_01ABC",
        "audio_index": 1,
        "stem_type": "lead_vocal",
    }

    jsonData, _ := json.Marshal(payload)

    req, _ := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
    req.Header.Set("Authorization", "Bearer <token>")
    req.Header.Set("Content-Type", "application/json")

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    body, _ := ioutil.ReadAll(resp.Body)
    fmt.Println(string(body))
}
```

```java Java theme={null}
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.URI;

public class Main {
    public static void main(String[] args) throws Exception {
        String url = "https://api.apimart.ai/v1/music/generations/stems";

        String payload = """
        {
          "model": "suno",
          "task_id": "task_01ABC",
          "audio_index": 1,
          "stem_type": "lead_vocal"
        }
        """;

        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(url))
            .header("Authorization", "Bearer <token>")
            .header("Content-Type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(payload))
            .build();

        HttpResponse<String> response = client.send(request,
            HttpResponse.BodyHandlers.ofString());

        System.out.println(response.body());
    }
}
```

```php PHP theme={null}
<?php

$url = "https://api.apimart.ai/v1/music/generations/stems";

$payload = [
    "model" => "suno",
    "task_id" => "task_01ABC",
    "audio_index" => 1,
    "stem_type" => "lead_vocal"
];

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
]);

$response = curl_exec($ch);
curl_close($ch);

echo $response;
?>
```

```ruby Ruby theme={null}
require 'net/http'
require 'json'
require 'uri'

url = URI("https://api.apimart.ai/v1/music/generations/stems")

payload = {
  model: "suno",
  task_id: "task_01ABC",
  audio_index: 1,
  stem_type: "lead_vocal"
}

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = "Bearer <token>"
request["Content-Type"] = "application/json"
request.body = payload.to_json

response = http.request(request)
puts response.body
```

```swift Swift theme={null}
import Foundation

let url = URL(string: "https://api.apimart.ai/v1/music/generations/stems")!

let payload: [String: Any] = [
    "model": "suno",
    "task_id": "task_01ABC",
    "audio_index": 1,
    "stem_type": "lead_vocal"
]

var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("Bearer <token>", forHTTPHeaderField: "Authorization")
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try? JSONSerialization.data(withJSONObject: payload)

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    if let error = error {
        print("Error: \(error)")
        return
    }

    if let data = data, let responseString = String(data: data, encoding: .utf8) {
        print(responseString)
    }
}

task.resume()
```

```csharp C# theme={null}
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        var url = "https://api.apimart.ai/v1/music/generations/stems";

        var payload = @"{
            ""model"": ""suno"",
            ""task_id"": ""task_01ABC"",
            ""audio_index"": 1,
            ""stem_type"": ""lead_vocal""
        }";

        using var client = new HttpClient();
        client.DefaultRequestHeaders.Add("Authorization", "Bearer <token>");

        var content = new StringContent(payload, Encoding.UTF8, "application/json");
        var response = await client.PostAsync(url, content);
        var result = await response.Content.ReadAsStringAsync();

        Console.WriteLine(result);
    }
}
```

```c C theme={null}
#include <stdio.h>
#include <curl/curl.h>

int main(void) {
    CURL *curl;
    CURLcode res;

    curl_global_init(CURL_GLOBAL_DEFAULT);
    curl = curl_easy_init();

    if(curl) {
        const char *url = "https://api.apimart.ai/v1/music/generations/stems";
        const char *payload = "{"
            "\"model\":\"suno\","
            "\"task_id\":\"task_01ABC\","
            "\"audio_index\":1,"
            "\"stem_type\":\"lead_vocal\""
        "}";

        struct curl_slist *headers = NULL;
        headers = curl_slist_append(headers, "Authorization: Bearer <token>");
        headers = curl_slist_append(headers, "Content-Type: application/json");

        curl_easy_setopt(curl, CURLOPT_URL, url);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, payload);
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);

        res = curl_easy_perform(curl);

        if(res != CURLE_OK) {
            fprintf(stderr, "curl_easy_perform() failed: %s\n",
                    curl_easy_strerror(res));
        }

        curl_slist_free_all(headers);
        curl_easy_cleanup(curl);
    }

    curl_global_cleanup();
    return 0;
}
```

```objectivec Objective-C theme={null}
#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSURL *url = [NSURL URLWithString:@"https://api.apimart.ai/v1/music/generations/stems"];

        NSDictionary *payload = @{
            @"model": @"suno",
            @"task_id": @"task_01ABC",
            @"audio_index": @1,
            @"stem_type": @"lead_vocal"
        };

        NSError *error;
        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:payload
                                                          options:0
                                                            error:&error];

        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
        [request setHTTPMethod:@"POST"];
        [request setValue:@"Bearer <token>" forHTTPHeaderField:@"Authorization"];
        [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
        [request setHTTPBody:jsonData];

        NSURLSessionDataTask *task = [[NSURLSession sharedSession]
            dataTaskWithRequest:request
            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                if (error) {
                    NSLog(@"Error: %@", error);
                    return;
                }
                NSString *result = [[NSString alloc] initWithData:data
                                                        encoding:NSUTF8StringEncoding];
                NSLog(@"%@", result);
            }];

        [task resume];
        [[NSRunLoop mainRunLoop] run];
    }
    return 0;
}
```

```ocaml OCaml theme={null}
(* Requires cohttp and yojson libraries *)
open Lwt
open Cohttp
open Cohttp_lwt_unix

let url = "https://api.apimart.ai/v1/music/generations/stems"

let payload = {|{
  "model": "suno",
  "task_id": "task_01ABC",
  "audio_index": 1,
  "stem_type": "lead_vocal"
}|}

let () =
  let headers = Header.init ()
    |> fun h -> Header.add h "Authorization" "Bearer <token>"
    |> fun h -> Header.add h "Content-Type" "application/json"
  in
  let body = Cohttp_lwt.Body.of_string payload in

  let response = Client.post ~headers ~body (Uri.of_string url) >>= fun (resp, body) ->
    body |> Cohttp_lwt.Body.to_string >|= fun body_str ->
    print_endline body_str
  in
  Lwt_main.run response
```

```dart Dart theme={null}
import 'dart:convert';
import 'package:http/http.dart' as http;

void main() async {
  final url = Uri.parse('https://api.apimart.ai/v1/music/generations/stems');

  final payload = {
    'model': 'suno',
    'task_id': 'task_01ABC',
    'audio_index': 1,
    'stem_type': 'lead_vocal'
  };

  final response = await http.post(
    url,
    headers: {
      'Authorization': 'Bearer <token>',
      'Content-Type': 'application/json',
    },
    body: jsonEncode(payload),
  );

  print(response.body);
}
```

```r R theme={null}
library(httr)
library(jsonlite)

url <- "https://api.apimart.ai/v1/music/generations/stems"

payload <- list(
  model = "suno",
  task_id = "task_01ABC",
  audio_index = 1,
  stem_type = "lead_vocal"
)

response <- POST(
  url,
  add_headers(
    Authorization = "Bearer <token>",
    `Content-Type` = "application/json"
  ),
  body = toJSON(payload, auto_unbox = TRUE),
  encode = "raw"
)

cat(content(response, "text"))
```

```json 200 theme={null}
{
  "code": 200,
  "data": [
    {
      "status": "submitted",
      "task_id": "task_01K8SGYNNNVBQTXNR4MM964S7K"
    }
  ]
}
```

```json 400 theme={null}
{
  "error": {
    "code": 400,
    "message": "请求参数无效",
    "type": "invalid_request_error"
  }
}
```

```json 401 theme={null}
{
  "error": {
    "code": 401,
    "message": "身份验证失败，请检查您的API密钥",
    "type": "authentication_error"
  }
}
```

```json 402 theme={null}
{
  "error": {
    "code": 402,
    "message": "账户余额不足，请充值后再试",
    "type": "payment_required"
  }
}
```

```json 403 theme={null}
{
  "error": {
    "code": 403,
    "message": "访问被禁止，您没有权限访问此资源",
    "type": "permission_error"
  }
}
```

```json 429 theme={null}
{
  "error": {
    "code": 429,
    "message": "请求过于频繁，请稍后再试",
    "type": "rate_limit_error"
  }
}
```

```json 500 theme={null}
{
  "error": {
    "code": 500,
    "message": "服务器内部错误，请稍后重试",
    "type": "server_error"
  }
}
```

```json 502 theme={null}
{
  "error": {
    "code": 502,
    "message": "网关错误，服务器暂时不可用",
    "type": "bad_gateway"
  }
}
```

## Authorizations

**Authorization** `string` *required*

所有接口均需要使用Bearer Token进行认证

获取 API Key：

访问 [API Key 管理页面](https://apimart.ai/keys) 获取您的 API Key

使用时在请求头中添加：

```
Authorization: Bearer YOUR_API_KEY
```

## Body

**model** `string` (default: suno)

音频模型。当前传 `suno`（不传默认 `suno`）。

**task\_id** `string` *required*

产出源音轨那次任务的 `task_id`；缺失或无法解析源时提交期直接返回 `400`。

**audio\_index** `integer` (default: 1)

引用源任务结果 `data.result.music[]` 中的第几首（1-based；默认 `1`；一次生成通常 2 首：索引 1 与 2）。

**stem\_type** `string` (default: lead\_vocal)

要提取的分轨类型。省略时默认使用 `lead_vocal`。常用值包括 `lead_vocal`、`backing_vocals`、`drum_kit`、`bass`、`piano` 和 `electric_guitar`。

> **查看全部 stem\_type 允许值**
>
> ```text theme={null}
> lead_vocal drum_kit bass backing_vocals piano electric_guitar percussion
> string_section synth acoustic_guitar sound_effects synth_pad synth_bass
> guitar brass_section organ electronic_drum_kit lead_electric_guitar synth_keys
> rhythm_electric_guitar electric_piano upright_bass keyboards distorted_electric_guitar
> kick snare risers synth_strings synth_lead woodwinds flute harp tambourine trumpet
> arpeggiator accordion fiddle pedal_steel_guitar synth_voice violin digital_piano
> synth_brass mandolin choir banjo bells clarinet tenor_saxophone trombone shaker
> french_horn glockenspiel electric_bass cello timpani harmonica marimba vibraphone
> lap_steel_guitar saxophone orchestra horns cymbals hand_clap oboe celesta congas
> drone alto_saxophone double_bass ukulele harpsichord baritone_saxophone xylophone
> tuba bass_guitar whistle lead_guitar rhodes 808 bongos bassoon cowbell viola sitar
> steel_drums piccolo theremin bagpipes hi_hat music_box melodica tabla koto djembe
> taiko didgeridoo
> ```
>
> `808` 必须作为字符串发送，例如 `"stem_type": "808"`。

**audio\_format** `string`

输出音频格式：`mp3` / `m4a` / `wav`。

> [!NOTE]
>
> **获取结果**：本接口为异步任务。提交后拿到 `task_id`，按 3–5s 间隔轮询 `GET /v1/music/tasks/{task_id}`，直到 `status` 为 `completed` 或 `failed`（生成中 `status` 可能为 `pending` 或 `processing`，`progress` 为 0–100 的整数且不保证按固定节点变化）。完成后结果里含分离出的轨 URL。失败时 `data.error.message` 为原因，自动退回预扣额度。

## Response

**code** `integer`

响应状态码

**data** `array`

返回数据数组

**属性**

**status** `string`

任务状态

* `submitted` - 已提交

**task\_id** `string`

任务唯一标识符（用于轮询 `GET /v1/music/tasks/{task_id}` 获取结果）


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