interface ICoreWebView2ExperimentalTextureStream

interface ICoreWebView2ExperimentalTextureStream
  : public IUnknown

This is the interface that handles texture streaming.

Summary

Applies to

Members

add_ErrorReceived

The ErrorReceived event is raised when an error with this texture stream occurs asynchronously.

public HRESULT add_ErrorReceived(ICoreWebView2ExperimentalTextureStreamErrorReceivedEventHandler * eventHandler, EventRegistrationToken * token)

add_StartRequested

Listens for stream requests from the Javascript's getTextureStream call for this stream's id.

public HRESULT add_StartRequested(ICoreWebView2ExperimentalTextureStreamStartRequestedEventHandler * eventHandler, EventRegistrationToken * token)

It is called for the first request only, and will not be called with subsequent requests of same stream id from any pages in the middle of request handling or after it returns success. The request is regarded as success only when the host provides the stream, Present API call, within 10s after being requested. The texture stream becomes 'Started' state once it starts sending a texture until it calls Stop API or receives 'Stopped' event.

add_Stopped

Listen to stop stream request once the stream started.

public HRESULT add_Stopped(ICoreWebView2ExperimentalTextureStreamStoppedEventHandler * eventHandler, EventRegistrationToken * token)

It is called when user stop all streaming requests from the renderers (Javascript) or the host calls the Stop API. The renderer can stream again by calling the streaming request API. The renderer cleared all registered Textures before sending the stop request event so that the callback of the next start request should register the textures again. The event is triggered when all requests for given stream id closed by the Javascript, or the host's Stop API call. texture related API calls after this event will return an error of HRESULT_FROM_WIN32(ERROR_INVALID_STATE).

add_WebTextureReceived

Event handler for receiving texture by Javascript.

public HRESULT add_WebTextureReceived(ICoreWebView2ExperimentalTextureStreamWebTextureReceivedEventHandler * eventHandler, EventRegistrationToken * token)

The WebTextureReceived event is raised when script sends a video frame to this texture stream. Allowed script will call chrome.webview. registerTextureStream to register a MediaStream with a specified texture stream. Video frames added to that MediaStream will be raised in the WebTextureReceived event. See registerTextureStream for details. Script is allowed to call registerTextureStream if it is from an HTML document with an origin allowed via ICoreWebView2TextureStream::AddAllowedOrigin with the alllowWebTexture parameter set. See AddAllowedOrigin for details.

add_WebTextureStreamStopped

The WebTextureStreamStopped event is raised when script unregisters its MediaStream from this texture stream.

public HRESULT add_WebTextureStreamStopped(ICoreWebView2ExperimentalTextureStreamWebTextureStreamStoppedEventHandler * eventHandler, EventRegistrationToken * token)

Script that has previously called chrome.webview.registerTextureStream, can call chrome.webview. unregisterTextureStream which will raise this event and then close associated ICoreWebView2WebTexture objects in the browser side. You should ensure that you release any references to associated ICoreWebView2WebTexture objects and their underlying resources. Once stopped, script may start again by calling chrome.webview. registerTextureStream and sending more frames. In this case the ICoreWebView2TextureStream WebTextureReceived event will be raised again.

AddAllowedOrigin

Adds an allowed URI origin.

public HRESULT AddAllowedOrigin(LPCWSTR origin, BOOL value)

The stream requests could be made from any frame, including iframes, but the origin of the page in the frames must be registered first in order for the request to succeed. The added origin will be persistent until ICoreWebView2ExperimentalTextureStream is destroyed or RemoveAllowedOrigin is called. The renderer does not support wildcard so it will compare literal string input to the requesting frame's page's origin after normalization. The page origin will be normalized so ASCII characters in the scheme and hostname will be lowercased, and non-ASCII characters in the hostname will be normalized to their punycode form. For example HTTPS://WWW.???.COM will be normalized to https://www.xn--kfk.com for comparison. So, the input string should have a scheme like https://. For example, https://www.valid-host.com, http://www.valid-host.com are valid origins but www.valid-host.com, or https://*.valid-host.com. are not valid origins. If invalid origin is provided, the API will return an error of E_INVALIDARG. getTextureStream() will fail unless the requesting frame's origin URI is added to the allowed origins. If value is TRUE, then the origin will also be added to WebTexture's allowed origin.

CloseTexture

Removes texture when the host removes the backed 2D texture.

public HRESULT CloseTexture(ICoreWebView2ExperimentalTexture * texture)

The host can save the resources by deleting 2D textures when it changes the frame sizes. The API will send a message to the browser where it will remove texture.

CreateTexture

Creates texture that will be referenced by the host and the browser.

public HRESULT CreateTexture(UINT32 widthInTexels, UINT32 heightInTexels, ICoreWebView2ExperimentalTexture ** texture)

By using the texture mechanism, the host does not have to send respective texture to the renderer, instead it notifies it with internal texture id, which is the identity of the texture. The texture is 2D texture, IDXGIResource, format and will be exposed through shared HANDLE or IUnknown type through ICoreWebView2ExperimentalTexture. Whenever the host has new texture to write, it should ask reusable ICoreWebView2ExperimentalTexture from the GetAvailableTexture, which returns ICoreWebView2ExperimentalTexture. If the GetAvailableTexture returns an error, then the host calls the CreateTexture to allocate new texture. The API also registers created shared handle to the browser once it created the resource.

Unit for width and height is texture unit (in texels) D3D11_TEXTURE2D_DESC.

get_Id

Get the stream ID of the object that is used when calling CreateTextureStream.

public HRESULT get_Id(LPWSTR * value)

The caller must free the returned string with CoTaskMemFree. See API Conventions. MSOWNERS: TBD (wv2core@microsoft.com)

GetAvailableTexture

Returns reuseable texture for video frame rendering.

public HRESULT GetAvailableTexture(ICoreWebView2ExperimentalTexture ** texture)

Once the renderer finishes rendering of texture's video frame, which was requested by Present, the renderer informs the host so that it can be reused. The host has to create new texture with CreateTexture if the API return an error HRESULT_FROM_WIN32(ERROR_NO_MORE_ITEMS).

PresentTexture

Adds the provided ICoreWebView2Texture to the video stream as the next frame.

public HRESULT PresentTexture(ICoreWebView2ExperimentalTexture * texture)

The ICoreWebView2Texture must not be closed. The ICoreWebView2Texture must have been obtained via a call to ICoreWebView2TextureStream::GetAvailableTexture or ICoreWebView2TextureStream::CreateTexture from this ICoreWebView2TextureStream. If the ICoreWebView2Texture is closed or was created from a different ICoreWebView2TextureStream this method will return E_INVALIDARG. You should write your video frame data to the ICoreWebView2Texture before calling this method. After this method completes WebView2 will take some time asynchronously to send the texture to the WebView2 processes to be added to the video stream. Do not close or otherwise change the provided ICoreWebView2Texture after calling this method. Doing so may result in the texture not being added to the texture stream and the ErrorReceived event may be raised.

remove_ErrorReceived

Remove listener for ErrorReceived event.

public HRESULT remove_ErrorReceived(EventRegistrationToken token)

remove_StartRequested

Remove listener for StartRequest event.

public HRESULT remove_StartRequested(EventRegistrationToken token)

remove_Stopped

Remove listener for Stopped event.

public HRESULT remove_Stopped(EventRegistrationToken token)

remove_WebTextureReceived

Remove listener for WebTextureReceived event.

public HRESULT remove_WebTextureReceived(EventRegistrationToken token)

remove_WebTextureStreamStopped

Remove listener for WebTextureStreamStopped event.

public HRESULT remove_WebTextureStreamStopped(EventRegistrationToken token)

RemoveAllowedOrigin

Remove added origin, which was added by AddAllowedOrigin.

public HRESULT RemoveAllowedOrigin(LPCWSTR origin)

The allowed or disallowed origins will take effect only when Javascript request a streaming. So, once the streaming started, it does not stop streaming.

SetD3DDevice

Set the D3D device this texture stream should use for creating shared texture resources.

public HRESULT SetD3DDevice(IUnknown * d3dDevice)

When the RenderAdapterLUIDChanged event is raised you should create a new D3D device using the RenderAdapterLUID property and call SetD3DDevice with the new D3D device. See the CreateTextureStream``d3dDevice parameter for more details.

Stop

Stops this texture stream from streaming and moves it into the stopped state.

public HRESULT Stop()

When moving to the stopped state the ICoreWebView2TextureStream Stopped event will be raised and in script the MediaStreamTrack ended event will be raised. Once stopped, script may again call Webview.getTextureStream moving the texture stream back to the start requested state. See the StartRequested event for details. Once stopped, calls to CreateTexture, GetAvailableTexture, PresentTexture, and CloseTexture will fail with HRESULT_FROM_WIN32(ERROR_INVALID_STATE). The Stop method is implicitly called when the texture stream object is destroyed.