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Analyzing Media

Getting Started with the Media Analyze API

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❗️

Beta API

This API is being made available as an early preview. If you have feedback on how you'd like to use the API please reach out to share your feedback with our team.

https://dolby.io/contact

The Dolby.io Analyze API is designed to give insight into your media. Our algorithms analyze your media and help identify problems by providing data about your audio's loudness, distortion, noise, silence, and quality. This can be helpful for specialized media processing tasks such as:

  • Quality control
  • Broadcasting recommendations
  • Content segmentation & analysis
  • etc.

This tutorial will show you how to get started quickly using the API to build a range of applications such as podcast tools, online learning platforms, and social video sharing.

⚠️

Not a Developer?

To get started without writing any code, you can use the Media API Demo to upload a file and view the results.

Getting started

To get started you'll follow these steps.

  1. Get your API token
  2. Prepare your media
  3. Make a Media Analyze request
  4. Check the results
  5. Review the output

1. Get your API Token

To use the Media Analyze API, you need an API token. To learn more about how to get an API token, see API Authentication.

2. Prepare your media

Make your media available for analysis:

a. Use your own cloud storage provider
b. Use our Dolby Media Input API

a. Use your own cloud storage provider

You will want to consider this option when you move your applications into production. Our services are able to work with many popular cloud storage services such as AWS S3, Azure Blob Storage, GCP Cloud Storage, or your own services with HTTP(s) and basic authentication.

See the Media Input and Output guide for more detail on various storage options.

b. Use our Dolby Media Input API (optional)

The Media Input API was designed to give you a quick way to upload media while evaluating Dolby.io Media API services. We can securely store your media temporarily, any media you upload will be removed regularly so shouldn't be used for permanent storage.

Call Start Media Input to identify a shortcut url. It must begin with dlb:// but otherwise is your own personal unique identifier. Some valid examples:

  • dlb://example.mp4
  • dlb://input/your-favorite-podcast.mp4
  • dlb://usr/home/me/voice-memo.wav

You can think of this like an object key that is used to identify a file for your account. Once you call POST /media/input you'll be returned a new url in the response. This is a pre-signed URL to a cloud storage location you will use to upload the file. You do that by making a PUT request with your media.

import os
import requests

# Set or replace these values

file_path = os.environ["INPUT_MEDIA_LOCAL_PATH"]

# Declare your dlb:// location

url = "https://api.dolby.com/media/input"
headers = {
    "Authorization": "Bearer {0}".format(api_token),
    "Content-Type": "application/json",
    "Accept": "application/json"
}

body = {
    "url": "dlb://in/example.mp4",
}

response = requests.post(url, json=body, headers=headers)
response.raise_for_status()
data = response.json()
presigned_url = data["url"]

# Upload your media to the pre-signed url response

print("Uploading {0} to {1}".format(file_path, presigned_url))
with open(file_path, "rb") as input_file:
  requests.put(presigned_url, data=input_file)

const fs = require("fs")
const axios = require("axios").default

// Set or replace these values

const file_path = process.env.INPUT_MEDIA_LOCAL_PATH

// Declare your dlb:// location

const config = {
  method: "post",
  url: "https://api.dolby.com/media/input",
  headers: {
    "Authorization": `Bearer ${api_token}`,
    "Content-Type": "application/json",
    "Accept": "application/json"
  },
  data: {
    url: "dlb://in/example.mp4",
  },
}

axios(config)
  .then(function(response) {
    // Upload your media to the pre-signed url response

    const upload_config = {
      method: "put",
      url: response.data.url,
      data: fs.createReadStream(file_path),
      headers: {
        "Content-Type": "application/octet-stream",
        "Content-Length": fs.statSync(file_path).size,
      },
    }
    axios(upload_config)
      .then(function() {
        console.log("File uploaded")
      })
      .catch(function(error) {
        console.log(error)
      })
  })
  .catch(function(error) {
    console.log(error)
  })

curl -X POST https://api.dolby.com/media/input \
    --header "Authorization: Bearer $API_TOKEN" \
    --header 'Content-Type: application/json' \
    --header 'Accept: application/json' \
    --data '{
      "url": "dlb://in/example.mp4"
    }'

# Use the result in a second command replacing `$PRE_SIGNED_URL` with the response from the previous command:

curl -X PUT $PRE_SIGNED_URL -T ./your-local-media.mp4

Once the upload is complete, you'll be able to refer to this media with the dlb://in/example.mp4 shortcut.

3. Make a Media Analyze request

The Analyze API requires both an input and output parameter to begin analyzing your media. There are additional parameters that can be used to customize the results based on the type of content and preferences you might have beyond the basic example here.

Regardless of whether you chose to use your own cloud storage or he Dolby.io /media/input service, the Dolby.io API will need to be able to read the media. See the Media Input and Output guide for a more detailed explanation of various ways you can provide authentication details.

These are all valid input values:

Similarly, for output you can use any location which our APIs will be able to write to. As this is less common, specifying a dlb:// output location will create one on the fly. Here are some examples:

import os
import requests

# Set or replace these values
body = {
  "input" : "s3://dolbyio/public/shelby/airplane.original.mp4",
  "output" : "dlb://out/airplane.analysis.json"
}

url = "https://api.dolby.com/media/analyze"
headers = {
    "Authorization": "Bearer {0}".format(api_token),
    "Content-Type": "application/json",
    "Accept": "application/json"
}

response = requests.post(url, json=body, headers=headers)
response.raise_for_status()
print(response.json())

const axios = require("axios").default

const config = {
  method: "post",
  url: "https://api.dolby.com/media/analyze",
  headers: {
    "Authorization": `Bearer ${api_token}`,
    "Content-Type": "application/json",
    "Accept": "application/json"
  },
  data: {
    input: "s3://dolbyio/public/shelby/airplane.original.mp4",
    output: "dlb://out/airplane.analysis.json",
  },
}

axios(config)
  .then(function(response) {
    console.log(response.data.job_id)
  })
  .catch(function(error) {
    console.log(error)
  })

curl -X POST https://api.dolby.com/media/analyze \
      --header "Authorization: Bearer $API_TOKEN" \
      --header 'Content-Type: application/json' \
      --header 'Accept: application/json' \
      --data '{
         "input": "s3://dolbyio/public/shelby/airplane.original.mp4",
         "output": "dlb://out/airplane.analysis.json"
     }'

The JSON response will include a unique job_id that you'll need to use to check on the status of media processing.

{"job_id":"b49955b4-9b64-4d8b-a4c6-2e3550472a33"}

You can explore the Analyze API reference to learn more about options to customize the behavior of the media processing.

4. Check the job status

It will take a few moments for the API to analyze your file. You'll need to check the status of the job. You can learn more about this in the How It Works section of the Introduction to learn more.

For this GET /media/analyze request you'll need to use the job id returned from the previous step. In these examples, it is specified as an environment variable that you'll need to set or replace in the code samples.

import os
import requests

url = "https://api.dolby.com/media/analyze"
headers = {
    "Authorization": "Bearer {0}".format(api_token),
    "Content-Type": "application/json",
    "Accept": "application/json"
}

# TODO: You must replace this value with the job ID returned from the previous step.

params = {
  "job_id": os.environ["DOLBYIO_JOB_ID"]
}

response = requests.get(url, params=params, headers=headers)
response.raise_for_status()
print(response.json())

const axios = require("axios").default

const config = {
  method: "get",
  url: "https://api.dolby.com/media/analyze",
  headers: {
     "Authorization": `Bearer ${api_token}`,
     "Content-Type": "application/json",
     "Accept": "application/json"
  },
  
  //TODO: You must replace this value with the job ID returned from the previous step.
  
  params: {
    job_id: process.env.DOLBYIO_JOB_ID,
  },
}

axios(config)
  .then(function(response) {
    console.log(JSON.stringify(response.data, null, 4))
  })
  .catch(function(error) {
    console.log(error)
  })

curl -X GET "https://api.dolby.com/media/analyze?job_id=$DOLBYIO_JOB_ID" \
     --header "Authorization: Bearer $API_TOKEN" \
     
     # TODO: You must replace this value with the job ID returned from the previous step.

While the job is still in progress, you will be able to see the status and progress values returned.

{
  "path": "/media/analyze",
  "status": "Running",
  "progress": 42
}

If you re-run and call again after a period of time you'll see the status changes and the output you originally specified will be ready for downloading.

{
  "path": "/media/analyze",
  "progress": 100,
  "result": {},
  "status": "Success"
}

5. Review the output

Once media processing is complete, the result file will be PUT in the output location specified when the job was started. If you used the optional Dolby.io temporary storage, you will need to follow a couple steps to download your media. For more information, see the Dolby.io Media Temporary Cloud Storage guide. 

import os
import shutil
import requests

output_path = os.environ["OUTPUT_MEDIA_LOCAL_PATH"]

url = "https://api.dolby.com/media/output"
headers = {
    "Authorization": "Bearer {0}".format(api_token),
    "Content-Type": "application/json",
    "Accept": "application/json"
}

args = {
    "url": "dlb://out/airplane.analysis.json",
}

with requests.get(url, params=args, headers=headers, stream=True) as response:
    response.raise_for_status()
    response.raw.decode_content = True
    print("Downloading from {0} into {1}".format(response.url, output_path))
    with open(output_path, "wb") as output_file:
        shutil.copyfileobj(response.raw, output_file)

const fs = require("fs")
const axios = require("axios").default

const output_path = process.env.OUTPUT_MEDIA_LOCAL_PATH

const config = {
  method: "get",
  url: "https://api.dolby.com/media/output",
  headers: {
    "Authorization": `Bearer ${api_token}`,
    "Content-Type": "application/json",
    "Accept": "application/json"
  },
  responseType: "stream",
  params: {
    url: "dlb://out/airplane.analysis.json",
  },
}

axios(config)
  .then(function(response) {
    response.data.pipe(fs.createWriteStream(output_path))
    response.data.on("error", function(error) {
      console.log(error)
    })
    response.data.on("end", function() {
      console.log("File downloaded!")
    })
  })
  .catch(function(error) {
    console.log(error)
  })

# You specify the `-L` because the service will redirect you to a cloud storage location. 
# You shouldn't try to retrieve directly from the cloud storage as the location may change, 
# so use **/media/output** with the shortcut instead. 
# The `-O` is to just output the file to your local system with the same filename.

curl  -X GET "https://api.dolby.com/media/output?url=dlb://out/airplane.analysis.json" \
      -O -L \
      --header "Authorization: Bearer $API_TOKEN" \

Review the results and check out the Analyze API reference if you have any questions about the data returned.

Learn more

Continue to learn about all this API can do by reviewing the Analyze API Guide. Pricing and other details are available from the product page.

Media Analyze API Guide
Process media to get insight into quality issues in a time series of processed regions of your media.
API Reference
Open API Specification to explore the parameters and responses.

Updated about 2 months ago