CVPixelBuffer newRenderedPixelBufferForRequest(AVAsynchronousVideoCompositionRequest request, out NSError error)
{
CVPixelBuffer dstPixels = null;
float tweenFactor = (float)factorForTimeInRange(request.CompositionTime, request.VideoCompositionInstruction.TimeRange);
var currentInstruction = (CustomVideoCompositionInstruction)request.VideoCompositionInstruction;
CVPixelBuffer foregroundSourceBuffer = request.SourceFrameByTrackID(currentInstruction.ForegroundTrackID);
CVPixelBuffer backgroundSourceBuffer = request.SourceFrameByTrackID(currentInstruction.BackgroundTrackID);
dstPixels = renderContext.CreatePixelBuffer();
if (renderContextDidChange)
{
var renderSize = renderContext.Size;
var destinationSize = new SizeF(dstPixels.Width, dstPixels.Height);
var renderContextTransform = new CGAffineTransform(renderSize.Width / 2, 0, 0, renderSize.Height / 2, renderSize.Width / 2, renderSize.Height / 2);
var destinationTransform = new CGAffineTransform(2 / destinationSize.Width, 0, 0, 2 / destinationSize.Height, -1, -1);
var normalizedRenderTransform = CGAffineTransform.Multiply(CGAffineTransform.Multiply(renderContextTransform, renderContext.RenderTransform), destinationTransform);
oglRender.RenderTransform = normalizedRenderTransform;
renderContextDidChange = false;
}
oglRender.RenderPixelBuffer(dstPixels, foregroundSourceBuffer, backgroundSourceBuffer, tweenFactor);
error = null;
return(dstPixels);
}
private CVPixelBuffer NewRenderedPixelBufferForRequest(AVAsynchronousVideoCompositionRequest request, out NSError error)
{
CVPixelBuffer dstPixels;
// tweenFactor indicates how far within that timeRange are we rendering this frame. This is normalized to vary between 0.0 and 1.0.
// 0.0 indicates the time at first frame in that videoComposition timeRange
// 1.0 indicates the time at last frame in that videoComposition timeRange
var tweenFactor = (float)FactorForTimeInRange(request.CompositionTime, request.VideoCompositionInstruction.TimeRange);
var currentInstruction = request.VideoCompositionInstruction as CustomVideoCompositionInstruction;
// Source pixel buffers are used as inputs while rendering the transition
var foregroundSourceBuffer = request.SourceFrameByTrackID(currentInstruction.ForegroundTrackId);
var backgroundSourceBuffer = request.SourceFrameByTrackID(currentInstruction.BackgroundTrackId);
// Destination pixel buffer into which we render the output
dstPixels = renderContext.CreatePixelBuffer();
// Recompute normalized render transform everytime the render context changes
if (renderContextDidChange)
{
// The renderTransform returned by the renderContext is in X: [0, w] and Y: [0, h] coordinate system
// But since in this sample we render using OpenGLES which has its coordinate system between [-1, 1] we compute a normalized transform
var renderSize = renderContext.Size;
var destinationSize = new CGSize(dstPixels.Width, dstPixels.Height);
var renderContextTransform = new CGAffineTransform(renderSize.Width / 2, 0, 0, renderSize.Height / 2, renderSize.Width / 2, renderSize.Height / 2);
var destinationTransform = new CGAffineTransform(2 / destinationSize.Width, 0, 0, 2 / destinationSize.Height, -1, -1);
var normalizedRenderTransform = CGAffineTransform.Multiply(CGAffineTransform.Multiply(renderContextTransform, renderContext.RenderTransform), destinationTransform);
Render.RenderTransform = normalizedRenderTransform;
renderContextDidChange = false;
}
Render.RenderPixelBuffer(dstPixels, foregroundSourceBuffer, backgroundSourceBuffer, tweenFactor);
error = null;
return(dstPixels);
}