void ComputeHistogram(VarArrayBuffer buffer)
{
var bufferSize = buffer.ByteLength;
if (bufferSize == 0)
{
return;
}
var bufferData = buffer.Map();
var max = double.MinValue;
for (uint i = 0; i < bufferSize; i++)
{
var index = bufferData[i];
histogram[index] += 1.0;
if (histogram[index] > max)
{
max = histogram[index];
}
}
//Normalize
for (uint i = 0; i < HISTOGRAM_SIZE; i++)
{
histogram[i] /= max;
}
}
/// Handler for messages coming in from the browser via postMessage(). The
/// @a var_message can contain anything: a JSON string; a string that encodes
/// method names and arguments; etc.
///
/// In this case, we only handle <code>pp::VarArrayBuffer</code>s. When we
/// receive one, we compute and display a histogram based on its contents.
///
/// @param[in] var_message The message posted by the browser.
private void OnHandleMessage(object sender, Var var_message)
{
if (var_message.IsArrayBuffer)
{
var buffer = new VarArrayBuffer(var_message);
ComputeHistogram(buffer);
DrawHistogram();
}
}
void PostDataMessage(byte[] buffer, uint size)
{
var dictionary = new VarDictionary();
dictionary.Set("name", "data");
VarArrayBuffer array_buffer = null;
byte[] dataPtr = null;
uint dataOffset = 0;
if (videoProfile == VideoProfile.Vp8Any ||
videoProfile == VideoProfile.Vp9Any)
{
uint frameOffset = 0;
if (encodedFrames == 1)
{
array_buffer = new VarArrayBuffer(size + ivfWriter.GetFileHeaderSize() + ivfWriter.GetFrameHeaderSize());
dataPtr = array_buffer.Map();
frameOffset = ivfWriter.WriteFileHeader(dataPtr, VideoProfileToString(videoProfile).ToUpper(),
frameSize.Width, frameSize.Height);
}
else
{
array_buffer = new VarArrayBuffer(size + ivfWriter.GetFrameHeaderSize());
dataPtr = array_buffer.Map();
}
var timestamp = frameTimeStampQueue.Peek();
frameTimeStampQueue.Dequeue();
dataOffset =
frameOffset +
ivfWriter.WriteFrameHeader(dataPtr, frameOffset, timestamp, size);
}
Array.Copy(buffer, 0, dataPtr, dataOffset, size);
// Make sure we flush the buffer data back to unmanaged memeory.
array_buffer.Flush();
array_buffer.Unmap();
dictionary.Set("data", array_buffer);
PostMessage(dictionary);
}
