/// <summary>
/// Generate a 15-bit video fingerprint from the input YUV244 buffer
/// This is currently unused but could be used to regenerate timecode on the destination video
/// if this has been lost in the trancode process. There are many other potential uses for this fingerprint data.
///
/// The algorithm divides the frame into 16 blocks (4x4) and applies the Hadamard masks to divide these blocks
/// into two sets in 15 different and orthogonal ways. The relative brightness of each pair of sets yields one
/// bit of the fingerprint. The entire fingerprint is comprised of 15 bits; one from each Hadamard mask.
/// The whole algorithm is resilient to changes of resolution, aspect, brightness, contrast and gamma that might occur in the
/// transcode process. It would be a simple matter to automatically detect letterboxing/pillarboxing and to only analyse the
/// active video area if this were required.
/// Testing with transcoded broadcast video has shown the fingerprint to be robust and reliable.
/// </summary>
/// <param name="videoFrame"></param>
/// <param name="sums"></param>
/// <returns></returns>
private unsafe int VideoFingerprint(IDeckLinkVideoInputFrame videoFrame, int[] sums)
{
var qheight = videoFrame.GetHeight() >> 2;
var qwidth = videoFrame.GetWidth() >> 2;
IntPtr buffer;
videoFrame.GetBytes(out buffer);
var ptr = (byte *)buffer + 1; // Skip over first U byte
for (var r = 0; r < qheight; r++)
{
for (var c = 0; c < qwidth; c++)
{
sums[0] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[1] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[2] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[3] += *ptr;
ptr += 2;
}
}
for (var r = 0; r < qheight; r++)
{
for (var c = 0; c < qwidth; c++)
{
sums[4] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[5] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[6] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[7] += *ptr;
ptr += 2;
}
}
for (var r = 0; r < qheight; r++)
{
for (var c = 0; c < qwidth; c++)
{
sums[8] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[9] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[10] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[11] += *ptr;
ptr += 2;
}
}
for (var r = 0; r < qheight; r++)
{
for (var c = 0; c < qwidth; c++)
{
sums[12] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[13] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[14] += *ptr;
ptr += 2;
}
for (var c = 0; c < qwidth; c++)
{
sums[15] += *ptr;
ptr += 2;
}
}
for (var i = 0; i < 16; i++)
{
sums[i] /= qwidth * qheight;
}
var videoFingerprint = 0;
var bit = 1;
for (var i = 0; i < 15; i++)
{
var sum = 0;
for (var j = 0; j < 16; j++)
{
sum += sums[j] * masks[i, j];
}
if (sum > 0)
{
videoFingerprint |= bit;
}
bit <<= 1;
}
return(videoFingerprint);
}
void IDeckLinkInputCallback.VideoInputFrameArrived(IDeckLinkVideoInputFrame videoFrame, IDeckLinkAudioInputPacket audioPacket)
{
if (videoFrame != null)
{
try
{
var frameFlags = videoFrame.GetFlags();
bool inputSignal = frameFlags.HasFlag(_BMDFrameFlags.bmdFrameHasNoInputSource);
if (inputSignal != validInputSignal)
{
validInputSignal = inputSignal;
InputSignalChanged?.Invoke(validInputSignal);
}
else
{
int width = videoFrame.GetWidth();
int height = videoFrame.GetHeight();
int stride = videoFrame.GetRowBytes();
var format = videoFrame.GetPixelFormat();
var bufferLength = stride * height;
videoFrame.GetBytes(out IntPtr pBuffer);
VideoDataArrived?.Invoke(pBuffer, bufferLength, 0);
//var f = File.Create(@"d:\testBMP2\" + DateTime.Now.ToString("HH_mm_ss_fff") + " " + width + "x" + height + "_" + format + ".raw");
//byte[] data = new byte[bufferLength];
//Marshal.Copy(pBuffer, data, 0, data.Length);
//f.Write(data, 0, data.Length);
//f.Close();
}
}
finally
{
Marshal.ReleaseComObject(videoFrame);
}
}
if (audioPacket != null)
{
try
{
long packetTime = 0;
//audioPacket.GetPacketTime(out packetTime, 30000);
int sampleSize = ((int)AudioSampleType / 8); //32bit
int samplesCount = audioPacket.GetSampleFrameCount();
int dataLength = sampleSize * AudioChannelsCount * samplesCount;
if (dataLength > 0)
{
audioPacket.GetBytes(out IntPtr pBuffer);
if (pBuffer != IntPtr.Zero)
{
byte[] data = new byte[dataLength];
Marshal.Copy(pBuffer, data, 0, data.Length);
AudioDataArrived?.Invoke(data, packetTime);
}
}
}
finally
{
Marshal.ReleaseComObject(audioPacket);
}
}
}
