wowza and streaming. lesson 7

id.241224001.763829

Lesson 7: Transcoding with Wowza REST API

In this lesson, we’ll focus on configuring transcoding using the Wowza REST API, with code examples in Node.js and Python.

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Step 1: Prerequisites

1. Enable Transcoder:

   • In the Wowza Streaming Engine Manager, navigate to the application (e.g., LiveStreamApp).

   • Go to the Transcoder section and enable the Transcoder AddOn.

2. API Authentication:

   • Ensure you have the REST API username and password.

---

Step 2: Configure a Transcoding Template

A transcoding template defines the output streams (e.g., different resolutions or bitrates). You can either create a custom template or modify an existing one.

Node.js Code: Create/Update Transcoder Template

1. Install Dependencies:

    npm install axios
   

2. Code:

    const axios = require('axios');
   
    const wowzaApiUrl = 'http://<server-ip>:8087/v2';
    const username = 'your-username';
    const password = 'your-password';
   
    async function updateTranscoderTemplate() {
        const templateConfig = {
            name: "custom-template",
            outputs: [
                {
                    name: "720p",
                    videoBitrate: 2000000,
                    audioBitrate: 128000,
                    width: 1280,
                    height: 720,
                    codec: "H.264"
                },
                {
                    name: "480p",
                    videoBitrate: 1000000,
                    audioBitrate: 128000,
                    width: 854,
                    height: 480,
                    codec: "H.264"
                }
            ]
        };
   
        try {
            const response = await axios.put(
                `${wowzaApiUrl}/servers/_defaultServer_/vhosts/_defaultVHost_/applications/LiveStreamApp/transcoder/templates/custom-template`,
                templateConfig,
                {
                    auth: { username, password },
                    headers: { 'Content-Type': 'application/json' }
                }
            );
            console.log('Transcoder template updated:', response.data);
        } catch (error) {
            console.error('Error updating transcoder template:', error.response.data);
        }
    }
   
    updateTranscoderTemplate();
   

---

Python Code: Create/Update Transcoder Template

1. Install Dependencies:

    pip install requests
   

2. Code:

    import requests
    from requests.auth import HTTPBasicAuth
   
    wowza_api_url = 'http://<server-ip>:8087/v2'
    username = 'your-username'
    password = 'your-password'
   
    def update_transcoder_template():
        template_config = {
            "name": "custom-template",
            "outputs": [
                {
                    "name": "720p",
                    "videoBitrate": 2000000,
                    "audioBitrate": 128000,
                    "width": 1280,
                    "height": 720,
                    "codec": "H.264"
                },
                {
                    "name": "480p",
                    "videoBitrate": 1000000,
                    "audioBitrate": 128000,
                    "width": 854,
                    "height": 480,
                    "codec": "H.264"
                }
            ]
        }
   
        url = f"{wowza_api_url}/servers/_defaultServer_/vhosts/_defaultVHost_/applications/LiveStreamApp/transcoder/templates/custom-template"
        try:
            response = requests.put(
                url,
                json=template_config,
                auth=HTTPBasicAuth(username, password)
            )
            if response.status_code == 200:
                print("Transcoder template updated:", response.json())
            else:
                print("Error:", response.status_code, response.json())
        except Exception as e:
            print("Error updating transcoder template:", e)
   
    update_transcoder_template()
   

---

Step 3: Start Transcoding

Node.js Code: Start Transcoding

async function startTranscoding() {
    const transcoderActionUrl = `${wowzaApiUrl}/servers/_defaultServer_/vhosts/_defaultVHost_/applications/LiveStreamApp/instances/_definst_/transcoder/actions/start`;

    try {
        const response = await axios.put(
            transcoderActionUrl,
            {},
            {
                auth: { username, password },
                headers: { 'Content-Type': 'application/json' }
            }
        );
        console.log('Transcoding started:', response.data);
    } catch (error) {
        console.error('Error starting transcoder:', error.response.data);
    }
}

startTranscoding();

Python Code: Start Transcoding

def start_transcoding():
    transcoder_action_url = f"{wowza_api_url}/servers/_defaultServer_/vhosts/_defaultVHost_/applications/LiveStreamApp/instances/_definst_/transcoder/actions/start"

    try:
        response = requests.put(
            transcoder_action_url,
            auth=HTTPBasicAuth(username, password)
        )
        if response.status_code == 200:
            print("Transcoding started:", response.json())
        else:
            print("Error:", response.status_code, response.json())
    except Exception as e:
        print("Error starting transcoder:", e)

start_transcoding()

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Step 4: Monitor Transcoding

Node.js Code: Monitor Transcoding

async function monitorTranscoding() {
    const transcoderStatusUrl = `${wowzaApiUrl}/servers/_defaultServer_/vhosts/_defaultVHost_/applications/LiveStreamApp/instances/_definst_/transcoder`;

    try {
        const response = await axios.get(
            transcoderStatusUrl,
            {
                auth: { username, password },
                headers: { 'Content-Type': 'application/json' }
            }
        );
        console.log('Transcoder status:', response.data);
    } catch (error) {
        console.error('Error monitoring transcoder:', error.response.data);
    }
}

monitorTranscoding();

Python Code: Monitor Transcoding

def monitor_transcoding():
    transcoder_status_url = f"{wowza_api_url}/servers/_defaultServer_/vhosts/_defaultVHost_/applications/LiveStreamApp/instances/_definst_/transcoder"

    try:
        response = requests.get(
            transcoder_status_url,
            auth=HTTPBasicAuth(username, password)
        )
        if response.status_code == 200:
            print("Transcoder status:", response.json())
        else:
            print("Error:", response.status_code, response.json())
    except Exception as e:
        print("Error monitoring transcoder:", e)

monitor_transcoding()

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Example Use Case

1. Scenario:

   • You want to stream a live event and create two renditions: 720p and 480p.

   • Transcoding should be active and monitored programmatically.

2. Steps:

   • Use the code to create/update the transcoding template.

   • Start the transcoder using Node.js or Python.

   • Monitor transcoder performance and outputs.

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Next Steps:

• Explore advanced transcoding features like audio-only streams or custom renditions.

• Automate transcoder controls with event-driven logic.