Video transcoding

Prerequisites

• Intelligent Media Management (IMM) is activated.

• You have created a bucket and uploaded the files to process to the bucket.

• You have created and bound an IMM project. You can bind the project in the OSS console or by calling an API. The IMM project must be in the same region as the bucket.

• You have the required permissions for the operations. Alibaba Cloud accounts have all permissions by default. RAM users and roles require authorization through a RAM policy or bucket policy.

  Permissions

  • Grant the user permissions to access related resources.

    • Grant the user permissions to use OSS for data processing.

      API	Action	Description
      GetObject	oss:GetObject	Downloads an object.
      	oss:GetObjectVersion	This permission is required to download a specific object version by using the versionId parameter.
      	kms:Decrypt	This permission is required if the object metadata contains X-Oss-Server-Side-Encryption: KMS.
      None	oss:ProcessImm	Allows you to use IMM to process data through OSS.
      PostProcessTask	oss:PostProcessTask	Allows you to use data processing features through POST requests, such as asynchronous processing (x-oss-async-process).

    • Grant the user permissions to use the media transcoding feature of IMM.

      API	Action	Description
      CreateMediaConvertTask	imm:CreateMediaConvertTask	Allows you to use IMM for media transcoding.

  • Grant the role used by the IMM service (by default, AliyunIMMDefaultRole with the resource ARN acs:ram:*:<account-id>:role/aliyunimmdefaultrole) permissions to access related resources for data processing.

    API	Action	Description
    None	ram:PassRole	Allows a user to pass a role to another service, enabling cross-service resource access.
    GetObject	oss:GetObject	Downloads an object.
    	oss:GetObjectVersion	This permission is required to download a specific object version by using the versionId parameter.
    	kms:Decrypt	This permission is required if the object metadata contains X-Oss-Server-Side-Encryption: KMS.
    HeadObject	oss:GetObject	Obtains the metadata of an object.
    PutObject	oss:PutObject	Uploads an object.
    	oss:PutObject	Required to upload objects to a versioning-enabled bucket.
    	kms:GenerateDataKey	These permissions are required to upload an object with KMS server-side encryption.
    	kms:Decrypt

Use the SDK

Video transcoding uses the asynchronous processing feature of the OSS SDKs for Java, Python, and Go.

import com.aliyun.oss.ClientBuilderConfiguration;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.AsyncProcessObjectRequest;
import com.aliyun.oss.model.AsyncProcessObjectResult;
import com.aliyuncs.exceptions.ClientException;

import java.util.Base64;

public class Demo {
    public static void main(String[] args) throws ClientException {
        // Set the endpoint. For example, if your bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Specify the region ID, for example, cn-hangzhou.
        String region = "cn-hangzhou";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the bucket name, for example, examplebucket.
        String bucketName = "examplebucket";
        // Specify the name of the output video file.
        String targetKey = "dest.avi";
        // Specify the name of the source video file.
        String sourceKey = "src.mp4";

        // Create an OSSClient instance.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Build the video processing style string that includes video transcoding parameters.
            String style = String.format("video/convert,f_avi,vcodec_h265,s_1920x1080,vb_2000000,fps_30,acodec_aac,ab_100000,sn_1");
            // Build the asynchronous processing instruction.
            String bucketEncoded = Base64.getUrlEncoder().withoutPadding().encodeToString(bucketName.getBytes());
            String targetEncoded = Base64.getUrlEncoder().withoutPadding().encodeToString(targetKey.getBytes());
            String process = String.format("%s|sys/saveas,b_%s,o_%s", style, bucketEncoded, targetEncoded);
            // Create an AsyncProcessObjectRequest object.
            AsyncProcessObjectRequest request = new AsyncProcessObjectRequest(bucketName, sourceKey, process);
            // Start the asynchronous processing task.
            AsyncProcessObjectResult response = ossClient.asyncProcessObject(request);
            System.out.println("EventId: " + response.getEventId());
            System.out.println("RequestId: " + response.getRequestId());
            System.out.println("TaskId: " + response.getTaskId());

        } finally {
            // Shut down the OSSClient instance to release resources.
            ossClient.shutdown();
        }
    }
}

# -*- coding: utf-8 -*-
import base64
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider


def main():
    # Set the endpoint. For example, if your bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
    endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
    # Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
    auth = oss2.ProviderAuthV4(EnvironmentVariableCredentialsProvider())

    # Specify the bucket name.
    bucket_name = 'examplebucket'
    # Specify the region ID, for example, cn-hangzhou.
    region = 'cn-hangzhou'
    # Create a Bucket object.
    bucket = oss2.Bucket(auth, endpoint, bucket_name, region=region)

    # Specify the name of the source video file.
    source_key = 'src.mp4'
    # Specify the name of the output video file.
    target_key = 'dest.avi'
    # Build the video processing style string that includes video transcoding parameters.
    style = 'video/convert,f_avi,vcodec_h265,s_1920x1080,vb_2000000,fps_30,acodec_aac,ab_100000,sn_1'
    # Build the asynchronous processing instruction.
    process = "{0}|sys/saveas,b_{1},o_{2}".format(style,
                                            oss2.compat.to_string(base64.urlsafe_b64encode(oss2.compat.to_bytes(bucket_name))).replace('=', ''),
                                            oss2.compat.to_string(base64.urlsafe_b64encode(oss2.compat.to_bytes(target_key))).replace('=', ''))

    # Call the asynchronous media processing API.
    try:
        # Start the asynchronous processing task.
        result = bucket.async_process_object(source_key, process)
        print(f"EventId: {result.event_id}")
        print(f"RequestId: {result.request_id}")
        print(f"TaskId: {result.task_id}")
    except Exception as e:
        print(f"Error: {e}")


if __name__ == "__main__":
    main()

package main

import (
	"encoding/base64"
	"fmt"
	"os"
	"strings"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
	// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Create an OSSClient instance.
	// Set the endpoint. For example, if your bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, specify the actual endpoint.
	client, err := oss.New("https://oss-cn-hangzhou.aliyuncs.com", "", "", oss.SetCredentialsProvider(&provider), oss.AuthVersion(oss.AuthV4), oss.Region("cn-hangzhou"))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Specify the bucket name, for example, examplebucket.
	bucketName := "examplebucket"
	bucket, err := client.Bucket(bucketName)
	// Specify the name of the output video file.
	targetObject := "dest.avi"
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Specify the name of the source video file.
	sourceObject := "src.mp4"

	// Build the video processing style string that includes video transcoding parameters.
	style := "video/convert,f_avi,vcodec_h265,s_1920x1080,vb_2000000,fps_30,acodec_aac,ab_100000,sn_1"
	// Build the asynchronous processing instruction.
	process := fmt.Sprintf("%s|sys/saveas,b_%v,o_%v", style, strings.TrimRight(base64.URLEncoding.EncodeToString([]byte(bucketName)), "="), strings.TrimRight(base64.URLEncoding.EncodeToString([]byte(targetObject)), "="))
	fmt.Printf("%#v\n", process)
	// Start the asynchronous processing task.
	rs, err := bucket.AsyncProcessObject(sourceObject, process)
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	fmt.Printf("EventId:%s\n", rs.EventId)
	fmt.Printf("RequestId:%s\n", rs.RequestId)
	fmt.Printf("TaskId:%s\n", rs.TaskId)
}

Convert AVI to MP4

POST /example.avi?x-oss-async-process HTTP/1.1
Host: video-demo.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 28 Oct 2022 06:40:10 GMT
Authorization: SignatureValue
 
// Transcode the example.avi object. The output is an MP4 file with an H.265 video stream (1920x1080, 30 fps, 2 Mbps) and an AAC audio stream (100 Kbps). Subtitles are disabled. The output is saved to oss://outbucket/outobjprefix.mp4.
x-oss-async-process=video/convert,f_mp4,vcodec_h265,s_1920x1080,vb_2000000,fps_30,acodec_aac,ab_100000,sn_1|sys/saveas,b_b3V0YnVja2V0,o_b3V0b2JqcHJlZml4LnthdXRvZXh0fQ

Convert AVI to TS

POST /example.avi?x-oss-async-process HTTP/1.1
Host: video-demo.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 28 Oct 2022 06:40:10 GMT
Authorization: SignatureValue
 
// Transcode the example.avi object.
x-oss-async-process=video/convert,ss_10000,t_60000,f_ts,vcodec_h264,vb_1000000,acodec_mp3,ab_100000/segment,f_hls,t_30000|sys/saveas,b_b3V0YnVja2V0,o_b3V0b2JqcHJlZml4LnthdXRvZXh0fQ/notify,topic_QXVkaW9Db252ZXJ0

Convert AVI to MP3

POST /example.avi?x-oss-async-process HTTP/1.1
Host: video-demo.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 28 Oct 2022 06:40:10 GMT
Authorization: SignatureValue
 
// Extract and transcode the audio stream from the example.avi object.
x-oss-async-process=video/convert,f_mp3,acodec_mp3,ab_100000,vn_1,sn_1|sys/saveas,b_b3V0YnVja2V0,o_b3V0b2JqcHJlZml4LnthdXRvZXh0fQ

"ResourceNotFound" error during video transcoding

The ResourceNotFound, The specified resource Attachment is not found. error indicates that no bucket is bound to your IMM project. Bind a bucket to the IMM project to resolve it. OSS data processing usage guide.

Saving output to the source path

No. The input path cannot be a prefix of the output path. This prevents unexpected behavior such as trigger loops or overwriting the source object.

Setting audio bit depth

Yes. Use the pixfmt parameter in an OSS x-oss-process request.

Getting task results with a task ID

Use the GetTask operation in IMM to retrieve task results.

Searching and deleting objects by suffix

No. OSS does not support searching for objects by suffix because it uses unordered storage.

Backend not receiving messages

Verify that the topic and subscription exist. If they do not exist or were deleted, reconfigure the subscription and restart transcoding.

Using a template for automatic transcoding

Yes. Configure triggers to automatically process new and existing videos in a bucket. Tasks, batch processing, and triggers support both system-defined and custom templates. Batch processing. Triggers.

Charges for transcoded videos

Yes. Transcoded videos occupy storage space, which incurs charges.

Saving output to the source path

Do not set the output path to be the same as the source path, as this will overwrite the source object.