Media

This guide gives an overview of the supported video and audio formats, describes how to control audio, get information about available web cameras and microphones, and other features.

Codecs

Google Chrome and Chromium differ in several ways, including the sets of audio and video codecs they support.

The table below displays which codecs are supported by the codebase of corresponding browsers.

As you can see in the table above, Google Chrome supports certain codecs while Chromium does not. The reason is that these codecs are proprietary and cannot be used in an open-source or a commercial project without obtaining licenses from the corresponding patent holders.

Different codecs have different patent holders. For example, to use H.264, companies must acquire the license from MPEG-LA company. You can read more about their license terms on the MPEG-LA’s website.

Proprietary codecs

Patent holders do not license codecs to the software that represents only a part of the final product deployed to the end users, for example, libraries like DotNetBrowser.

To support H.264, HEVC and AAC in your products, you need to purchase appropriate licenses and enable the following proprietary features:

engine = EngineFactory.Create(new EngineOptions.Builder
{
    RenderingMode = RenderingMode.HardwareAccelerated,
    ProprietaryFeatures = ProprietaryFeatures.H264 |
                          ProprietaryFeatures.Aac |
                          ProprietaryFeatures.Hevc
}.Build());

engine = EngineFactory.Create(New EngineOptions.Builder With 
{
    .RenderingMode = RenderingMode.HardwareAccelerated,
    .ProprietaryFeatures = ProprietaryFeatures.H264 Or
                           ProprietaryFeatures.Aac Or
                           ProprietaryFeatures.Hevc
}.Build())

After providing the license information and enabling proprietary features, you can load web pages with the AAC, H.264 and HEVC formats, and play audio and video files, just like in Google Chrome. By default, the proprietary codecs are disabled.

The H.264, HEVC and AAC codecs are the proprietary components. By enabling these codecs you state that you are aware that H.264, HEVC and AAC are the proprietary components, and you should have a license in order to use them. For more information, you could contact the patent holders: Via Licensing and MPEG LA. TeamDev shall not be responsible for your use of the H.264, HEVC and AAC codecs.

Video

DotNetBrowser fully supports HTML5 <video> element and can play video in the supported formats.

If the library cannot play a video, or a video format is unsupported, DotNetBrowser suggests to download the video file. For details, refer to Downloads section containing the instructions on managing downloads.

Audio

Controlling audio

Using IAudioController you can find out whether audio is playing on the loaded web page:

bool audioPlaying = browser.Audio.IsPlaying;

Dim audioPlaying As Boolean = browser.Audio.IsPlaying

You can mute or unmute audio on the loaded web page if required:

browser.Audio.Muted = true;
browser.Audio.Muted = false;

browser.Audio.Muted = True
browser.Audio.Muted = False

To check whether audio is muted, use the following code:

bool audioMuted = browser.Audio.Muted;

Dim audioMuted As Boolean = browser.Audio.Muted

Audio events

To find out whether audio has started/stopped playing on the loaded web page, you can subscribe to the following events:

browser.Audio.AudioPlaybackStarted += (s, e) => { };
browser.Audio.AudioPlaybackStopped += (s, e) => { };

AddHandler browser.Audio.AudioPlaybackStarted, Sub(s, e)
End Sub
AddHandler browser.Audio.AudioPlaybackStopped, Sub(s, e)
End Sub

DRM

Widevine

The web services like Netflix or Amazon Prime use Widevine to distribute their DRM-encoded content. Widevine is a Google proprietary component and is disabled by default. To enable it and play the DRM-encoded content, use the code sample below:

engine = EngineFactory.Create(new EngineOptions.Builder
{
    RenderingMode = RenderingMode.HardwareAccelerated,
    ProprietaryFeatures = ProprietaryFeatures.Widevine
}.Build());

engine = EngineFactory.Create(New EngineOptions.Builder With 
{
    .RenderingMode = RenderingMode.HardwareAccelerated,
    .ProprietaryFeatures = ProprietaryFeatures.Widevine
}.Build())

Widevine is a Google proprietary component, governed by its own terms of use. For more information, refer to Widevine.

Camera & microphone

DotNetBrowser supports a web camera and microphone. You can get information about all available media stream devices using the code sample below:

IMediaDevices mediaDevices = engine.MediaDevices;

// Get all available video devices, e.g. web camera.
IEnumerable<MediaDevice> videoDevices = mediaDevices.VideoCaptureDevices;

// Get all available audio devices, e.g. microphone.
IEnumerable<MediaDevice> audioDevices = mediaDevices.AudioCaptureDevices;

Dim mediaDevices As IMediaDevices = engine.MediaDevices

' Get all available video devices, e.g. web camera.
Dim videoDevices As IEnumerable(Of MediaDevice) = mediaDevices.VideoCaptureDevices

' Get all available audio devices, e.g. microphone.
Dim audioDevices As IEnumerable(Of MediaDevice) = mediaDevices.AudioCaptureDevices

You can detect when media capturing starts or stops using these events:

Browser.MediaStreamCaptureStarted += (sender, args) =>
{
    Console.WriteLine($"Started capturing {args.MediaStreamType}"); 
};

Browser.MediaStreamCaptureStopped += (sender, args) =>
{
    Console.WriteLine($"Stopped capturing {args.MediaStreamType}");  
};

AddHandler Browser.MediaStreamCaptureStarted, Sub(sender, args)
    Console.WriteLine($"Started capturing {args.MediaStreamType}")
End Sub

AddHandler Browser.MediaStreamCaptureStopped, Sub(sender, args)
    Console.WriteLine($"Stopped capturing {args.MediaStreamType}")
End Sub

Selecting a media device

You can have multiple webcams and microphones in your environment. When a web page wants to use one of them, you can use SelectMediaDeviceHandler to instruct the web page on which device to use.

The code sample below demonstrates how to select the first device from the list of available ones:

mediaDevices.SelectMediaDeviceHandler = 
    new Handler<SelectMediaDeviceParameters, SelectMediaDeviceResponse>(p =>
    {
        return SelectMediaDeviceResponse.Select(p.Devices.FirstOrDefault());
    });

mediaDevices.SelectMediaDeviceHandler = 
    New Handler(Of SelectMediaDeviceParameters, SelectMediaDeviceResponse)(Function(p)
        Return SelectMediaDeviceResponse.Select(p.Devices.FirstOrDefault())
    End Function)

The handler will not be invoked if there are no media input devices of the requested type.

If you want to restrict the access to your microphone or webcam for a particular webpage, you can use RequestPermissionHandler as shown in the code sample below:

engine.Profiles.Default.Permissions.RequestPermissionHandler = 
    new Handler<RequestPermissionParameters, RequestPermissionResponse>(p => 
    {
        if (p.Type == PermissionType.AudioCapture || p.Type == PermissionType.VideoCapture)
        {
            return RequestPermissionResponse.Deny();
        }
        return RequestPermissionResponse.Grant();
    });

engine.Profiles.Default.Permissions.RequestPermissionHandler =
    New Handler(Of RequestPermissionParameters, RequestPermissionResponse)(Function(p)
        Dim type = p.Type
        If type = PermissionType.AudioCapture OrElse type = PermissionType.VideoCapture Then
            Return RequestPermissionResponse.Deny()
        End If
        Return RequestPermissionResponse.Grant()
    End Function)