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Optimize pixel drawing.

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Optimize byte to double conversion.
Other small optimizations/cleanups/fixes.
This commit is contained in:
J.D. Purcell 2015-09-02 23:37:56 -04:00
parent 456bf7c090
commit 7fa4accd64
2 changed files with 47 additions and 36 deletions
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16
libse/FastBitmap.cs
View File

@ -8,13 +8,21 @@ namespace Nikse.SubtitleEdit.Core
{
unsafe public class FastBitmap
{
private struct PixelData
public struct PixelData
{
public byte Blue;
public byte Green;
public byte Red;
public byte Alpha;
public PixelData(Color c)
{
Alpha = c.A;
Red = c.R;
Green = c.G;
Blue = c.B;
}
public override string ToString()
{
return "(" + Alpha + ", " + Red + ", " + Green + ", " + Blue + ")";
@ -82,6 +90,12 @@ namespace Nikse.SubtitleEdit.Core
data->Blue = color.B;
}
public void SetPixel(int x, int y, PixelData color)
{
var data = (PixelData*)(_pBase + y * _width + x * sizeof(PixelData));
*data = color;
}
public void SetPixel(int x, int y, Color color, int length)
{
var data = (PixelData*)(_pBase + y * _width + x * sizeof(PixelData));

67
libse/WaveToVisualizer.cs
View File

@ -227,7 +227,7 @@ namespace Nikse.SubtitleEdit.Core
{
PeaksPerSecond = peaksPerSecond;
ReadSampleDataValueDelegate readSampleDataValue = GetSampleDataRerader();
ReadSampleDataValueDelegate readSampleDataValue = GetSampleDataReader();
DataMinValue = int.MaxValue;
DataMaxValue = int.MinValue;
PeakSamples = new List<int>();
@ -266,7 +266,7 @@ namespace Nikse.SubtitleEdit.Core
public void GenerateAllSamples()
{
// determine how to read sample values
ReadSampleDataValueDelegate readSampleDataValue = GetSampleDataRerader();
ReadSampleDataValueDelegate readSampleDataValue = GetSampleDataReader();
// load data
_data = new byte[Header.DataChunkSize];
@ -333,7 +333,9 @@ namespace Nikse.SubtitleEdit.Core
private int ReadValue16Bit(ref int index)
{
int result = BitConverter.ToInt16(_data, index);
int result = (short)(
(_data[index ] ) |
(_data[index + 1] << 8));
index += 2;
return result;
}
@ -361,7 +363,7 @@ namespace Nikse.SubtitleEdit.Core
/// Determine how to read sample values
/// </summary>
/// <returns>Sample data reader that matches bits per sample</returns>
private ReadSampleDataValueDelegate GetSampleDataRerader()
private ReadSampleDataValueDelegate GetSampleDataReader()
{
ReadSampleDataValueDelegate readSampleDataValue;
switch (Header.BitsPerSample)
@ -403,8 +405,8 @@ namespace Nikse.SubtitleEdit.Core
List<Bitmap> bitmaps = new List<Bitmap>();
SpectrogramDrawer drawer = new SpectrogramDrawer(nfft);
ReadSampleDataValueDelegate readSampleDataValue = GetSampleDataRerader();
double sampleScale = 1.0 / Math.Pow(2.0, Header.BitsPerSample - 1);
ReadSampleDataValueDelegate readSampleDataValue = GetSampleDataReader();
double sampleScale = 1.0 / (Math.Pow(2.0, Header.BitsPerSample - 1) * Header.NumberOfChannels);
int delaySampleCount = (int)(Header.SampleRate * (delayInMilliseconds / TimeCode.BaseUnit));
@ -467,9 +469,6 @@ namespace Nikse.SubtitleEdit.Core
{
value += readSampleDataValue(ref dataByteOffset);
}
value /= Header.NumberOfChannels;
if (value < DataMinValue) DataMinValue = value;
if (value > DataMaxValue) DataMaxValue = value;
chunkSamples[chunkSampleOffset] = value * sampleScale;
chunkSampleOffset += 1;
}
@ -504,10 +503,12 @@ namespace Nikse.SubtitleEdit.Core
private class SpectrogramDrawer
{
private const double raisedCosineWindowScale = 0.5;
private int _nfft;
private MagnitudeToIndexMapper _mapper;
private RealFFT _fft;
private Color[] _palette;
private FastBitmap.PixelData[] _palette;
private double[] _segment;
private double[] _window;
private double[] _magnitude;
@ -521,43 +522,39 @@ namespace Nikse.SubtitleEdit.Core
_segment = new double[nfft];
_window = CreateRaisedCosineWindow(nfft);
_magnitude = new double[nfft / 2];
double scaleCorrection = 1.0 / (raisedCosineWindowScale * _fft.ForwardScaleFactor);
for (int i = 0; i < _window.Length; i++)
{
_window[i] *= scaleCorrection;
}
}
public Bitmap Draw(double[] samples)
{
const int overlap = 0;
int numSamples = samples.Length;
int colIncrement = _nfft * (1 - overlap);
int numcols = numSamples / colIncrement;
// make sure we don't step beyond the end of the recording
while ((numcols - 1) * colIncrement + _nfft > numSamples)
numcols--;
const double raisedCosineWindowScale = 0.5;
double scaleCorrection = 1.0 / (raisedCosineWindowScale * _fft.ForwardScaleFactor);
var bmp = new FastBitmap(new Bitmap(numcols, _nfft / 2));
int width = samples.Length / _nfft;
int height = _nfft / 2;
var bmp = new FastBitmap(new Bitmap(width, height));
bmp.LockImage();
for (int col = 0; col < numcols; col++)
for (int x = 0; x < width; x++)
{
// read a segment of the recorded signal
for (int c = 0; c < _nfft; c++)
for (int i = 0; i < _nfft; i++)
{
_segment[c] = samples[col * colIncrement + c] * _window[c] * scaleCorrection;
_segment[i] = samples[x * _nfft + i] * _window[i];
}
// transform to the frequency domain
_fft.ComputeForward(_segment);
// and compute the magnitude spectrum
// compute the magnitude of the spectrum
MagnitudeSpectrum(_segment, _magnitude);
// Draw
for (int newY = 0; newY < _nfft / 2 - 1; newY++)
// draw
for (int y = 0; y < height; y++)
{
int colorIndex = _mapper.Map(_magnitude[newY]);
bmp.SetPixel(col, (_nfft / 2 - 1) - newY, _palette[colorIndex]);
int colorIndex = _mapper.Map(_magnitude[y]);
bmp.SetPixel(x, height - y - 1, _palette[colorIndex]);
}
}
bmp.UnlockImage();
@ -585,13 +582,13 @@ namespace Nikse.SubtitleEdit.Core
return a * a + b * b;
}
private static Color[] GeneratePalette(int nfft)
private static FastBitmap.PixelData[] GeneratePalette(int nfft)
{
Color[] palette = new Color[nfft];
var palette = new FastBitmap.PixelData[nfft];
if (Configuration.Settings.VideoControls.SpectrogramAppearance == "Classic")
{
for (int colorIndex = 0; colorIndex < nfft; colorIndex++)
palette[colorIndex] = PaletteValue(colorIndex, nfft);
palette[colorIndex] = new FastBitmap.PixelData(PaletteValue(colorIndex, nfft));
}
else
{
@ -599,7 +596,7 @@ namespace Nikse.SubtitleEdit.Core
Configuration.Settings.VideoControls.WaveformColor.G,
Configuration.Settings.VideoControls.WaveformColor.B, nfft);
for (int i = 0; i < nfft; i++)
palette[i] = list[i];
palette[i] = new FastBitmap.PixelData(list[i]);
}
return palette;
}