Raw video with alpha channel

Alpha channel mode produces a per-pixel alpha mask alongside the raw video frame, which you can use to remove the background or composite the user over custom content.

Turn on alpha channel mode

Not every device can produce an alpha mask, so check support before enabling it. Confirm the device supports alpha channel mode with isDeviceSupportAlphaChannelMode, and that the session currently allows it with canEnableAlphaChannelMode. Then turn it on with enableAlphaChannelMode, and read the current state with isAlphaChannelModeEnabled.

IZoomVideoSDKVideoHelper* pVideoHelper = m_pVideoSDK->getVideoHelper();
if (pVideoHelper->isDeviceSupportAlphaChannelMode() && pVideoHelper->canEnableAlphaChannelMode())
{
    pVideoHelper->enableAlphaChannelMode(true);
}
bool isOn = pVideoHelper->isAlphaChannelModeEnabled();

Read the alpha mask

With alpha channel mode on, the alpha mask arrives alongside the YUV planes in onRawDataFrameReceived. Read it with GetAlphaBuffer and GetAlphaBufferLen on the YUVRawDataI420 frame. For the full subscription and frame-reading flow, see Receive raw data.

void CExampleRenderer::onRawDataFrameReceived(YUVRawDataI420* data_)
{
    char* alphaBuffer = data_->GetAlphaBuffer();
    unsigned int alphaLen = data_->GetAlphaBufferLen();
    // Composite the frame using the alpha mask.
}

Alpha channel callbacks

The SDK calls onVideoAlphaChannelStatusChanged when alpha channel mode turns on or off.

void CExampleListener::onVideoAlphaChannelStatusChanged(bool isAlphaModeOn)
{
    // Respond to the alpha channel mode change.
}