mirror of
https://github.com/SubtitleEdit/subtitleedit.git
synced 2024-11-22 19:22:53 +01:00
1012 lines
39 KiB
C#
1012 lines
39 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Drawing;
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using System.Globalization;
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using System.IO;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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using System.Xml;
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namespace Nikse.SubtitleEdit.Core
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{
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/// <summary>
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/// http://soundfile.sapp.org/doc/WaveFormat
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/// </summary>
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public class WaveHeader
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{
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private const int ConstantHeaderSize = 20;
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public const int AudioFormatPcm = 1;
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public string ChunkId { get; private set; }
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public uint ChunkSize { get; private set; }
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public string Format { get; private set; }
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public string FmtId { get; private set; }
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public int FmtChunkSize { get; private set; }
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/// <summary>
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/// 1 = PCM (uncompressed)
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/// 0x0101 = IBM mu-law format
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/// 0x0102 = IBM a-law format
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/// 0x0103 = IBM AVC Adaptive Differential Pulse Code Modulation format
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/// 0xFFFE = WAVE_FORMAT_EXTENSIBLE, Determined by SubFormat
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/// </summary>
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public int AudioFormat { get; private set; }
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public int NumberOfChannels { get; private set; }
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/// <summary>
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/// Number of samples per second
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/// </summary>
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public int SampleRate { get; private set; }
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/// <summary>
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/// Should be SampleRate * BlockAlign
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/// </summary>
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public int ByteRate { get; private set; }
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/// <summary>
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/// 8 bytes per block (32 bit); 6 bytes per block (24 bit); 4 bytes per block (16 bit)
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/// </summary>
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public int BlockAlign { get; private set; }
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public int BitsPerSample { get; private set; }
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public string DataId { get; private set; }
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/// <summary>
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/// Size of sound data
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/// </summary>
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public uint DataChunkSize { get; private set; }
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public int DataStartPosition { get; private set; }
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public WaveHeader(Stream stream)
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{
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stream.Position = 0;
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var buffer = new byte[ConstantHeaderSize];
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int bytesRead = stream.Read(buffer, 0, buffer.Length);
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if (bytesRead < buffer.Length)
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throw new ArgumentException("Stream is too small");
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// constant header
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ChunkId = Encoding.UTF8.GetString(buffer, 0, 4); // Chunk ID: "RIFF" (Resource Interchange File Format), RF64 = new 64-bit format - see http://tech.ebu.ch/docs/tech/tech3306-2009.pdf
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ChunkSize = BitConverter.ToUInt32(buffer, 4); // Chunk size: 16 or 18 or 40
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Format = Encoding.UTF8.GetString(buffer, 8, 4); // Format code - "WAVE"
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FmtId = Encoding.UTF8.GetString(buffer, 12, 4); // Contains the letters "fmt "
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FmtChunkSize = BitConverter.ToInt32(buffer, 16); // 16 for PCM. This is the size of the rest of the Subchunk which follows this number.
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// fmt data
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buffer = new byte[FmtChunkSize];
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stream.Read(buffer, 0, buffer.Length);
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AudioFormat = BitConverter.ToInt16(buffer, 0); // PCM = 1
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NumberOfChannels = BitConverter.ToInt16(buffer, 2);
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SampleRate = BitConverter.ToInt32(buffer, 4); // 8000, 44100, etc.
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ByteRate = BitConverter.ToInt32(buffer, 8); // SampleRate * NumChannels * BitsPerSample/8
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BlockAlign = BitConverter.ToInt16(buffer, 12);
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BitsPerSample = BitConverter.ToInt16(buffer, 14); // 8 bits = 8, 16 bits = 16, etc.
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// data
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buffer = new byte[8];
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stream.Position = ConstantHeaderSize + FmtChunkSize;
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stream.Read(buffer, 0, buffer.Length);
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DataId = Encoding.UTF8.GetString(buffer, 0, 4);
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DataChunkSize = BitConverter.ToUInt32(buffer, 4);
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DataStartPosition = ConstantHeaderSize + FmtChunkSize + 8;
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// if some other ChunckId than 'data' (e.g. LIST) we search for 'data'
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long oldPos = ConstantHeaderSize + FmtChunkSize;
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while (DataId != "data" && oldPos + DataChunkSize + 16 < stream.Length)
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{
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oldPos = oldPos + DataChunkSize + 8;
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stream.Position = oldPos;
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stream.Read(buffer, 0, buffer.Length);
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DataId = Encoding.UTF8.GetString(buffer, 0, 4);
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DataChunkSize = BitConverter.ToUInt32(buffer, 4);
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DataStartPosition = (int)oldPos + 8;
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}
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// recalculate BlockAlign (older versions wrote incorrect values)
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BlockAlign = BytesPerSample * NumberOfChannels;
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}
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public int BytesPerSample
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{
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get
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{
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// round up to the next byte (20 bit WAVs are like 24 bit WAVs with the 4 least significant bits unused)
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return (BitsPerSample + 7) / 8;
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}
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}
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public long BytesPerSecond
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{
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get
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{
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return (long)SampleRate * BlockAlign;
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}
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}
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public double LengthInSeconds
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{
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get
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{
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return (double)DataChunkSize / BytesPerSecond;
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}
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}
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public long LengthInSamples
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{
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get
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{
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return DataChunkSize / BlockAlign;
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}
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}
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internal static void WriteHeader(Stream toStream, int sampleRate, int numberOfChannels, int bitsPerSample, int sampleCount)
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{
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const int headerSize = 44;
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int bytesPerSample = (bitsPerSample + 7) / 8;
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int blockAlign = numberOfChannels * bytesPerSample;
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int byteRate = sampleRate * blockAlign;
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int dataSize = sampleCount * bytesPerSample * numberOfChannels;
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byte[] header = new byte[headerSize];
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WriteStringToByteArray(header, 0, "RIFF");
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WriteInt32ToByteArray(header, 4, headerSize + dataSize - 8); // size of RIFF chunk's data
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WriteStringToByteArray(header, 8, "WAVE");
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WriteStringToByteArray(header, 12, "fmt ");
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WriteInt32ToByteArray(header, 16, 16); // size of fmt chunk's data
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WriteInt16ToByteArray(header, 20, 1); // format, 1 = PCM
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WriteInt16ToByteArray(header, 22, numberOfChannels);
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WriteInt32ToByteArray(header, 24, sampleRate);
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WriteInt32ToByteArray(header, 28, byteRate);
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WriteInt16ToByteArray(header, 32, blockAlign);
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WriteInt16ToByteArray(header, 34, bitsPerSample);
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WriteStringToByteArray(header, 36, "data");
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WriteInt32ToByteArray(header, 40, dataSize);
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toStream.Write(header, 0, headerSize);
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}
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private static void WriteInt16ToByteArray(byte[] headerData, int index, int value)
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{
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byte[] buffer = BitConverter.GetBytes((short)value);
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Buffer.BlockCopy(buffer, 0, headerData, index, buffer.Length);
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}
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private static void WriteInt32ToByteArray(byte[] headerData, int index, int value)
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{
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byte[] buffer = BitConverter.GetBytes(value);
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Buffer.BlockCopy(buffer, 0, headerData, index, buffer.Length);
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}
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private static void WriteStringToByteArray(byte[] headerData, int index, string value)
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{
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byte[] buffer = Encoding.ASCII.GetBytes(value);
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Buffer.BlockCopy(buffer, 0, headerData, index, buffer.Length);
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}
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}
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public struct WavePeak
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{
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public readonly short Max;
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public readonly short Min;
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public WavePeak(short max, short min)
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{
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Max = max;
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Min = min;
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}
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public int Abs
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{
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get { return Math.Max(Math.Abs((int)Max), Math.Abs((int)Min)); }
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}
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}
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public class WavePeakData
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{
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public WavePeakData(int sampleRate, IList<WavePeak> peaks)
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{
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SampleRate = sampleRate;
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LengthInSeconds = (double)peaks.Count / sampleRate;
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Peaks = peaks;
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CalculateHighestPeak();
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}
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public int SampleRate { get; private set; }
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public double LengthInSeconds { get; private set; }
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public IList<WavePeak> Peaks { get; private set; }
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public int HighestPeak { get; private set; }
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private void CalculateHighestPeak()
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{
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HighestPeak = 0;
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foreach (var peak in Peaks)
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{
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int abs = peak.Abs;
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if (abs > HighestPeak)
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HighestPeak = abs;
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}
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}
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public static WavePeakData FromDisk(string peakFileName)
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{
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using (var peakGenerator = new WavePeakGenerator(peakFileName))
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{
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return peakGenerator.LoadPeaks();
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}
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}
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}
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public class SpectrogramData : IDisposable
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{
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private string _loadFromDirectory;
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public SpectrogramData(int fftSize, int imageWidth, double sampleDuration, IList<Bitmap> images)
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{
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FftSize = fftSize;
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ImageWidth = imageWidth;
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SampleDuration = sampleDuration;
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Images = images;
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}
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private SpectrogramData(string loadFromDirectory)
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{
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_loadFromDirectory = loadFromDirectory;
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Images = new Bitmap[0];
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}
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public int FftSize { get; private set; }
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public int ImageWidth { get; private set; }
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public double SampleDuration { get; private set; }
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public IList<Bitmap> Images { get; private set; }
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public bool IsLoaded
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{
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get { return _loadFromDirectory == null; }
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}
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public void Load()
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{
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if (_loadFromDirectory == null)
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return;
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string directory = _loadFromDirectory;
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_loadFromDirectory = null;
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try
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{
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string xmlInfoFileName = Path.Combine(directory, "Info.xml");
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if (!File.Exists(xmlInfoFileName))
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return;
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var doc = new XmlDocument();
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var culture = CultureInfo.InvariantCulture;
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doc.Load(xmlInfoFileName);
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FftSize = Convert.ToInt32(doc.DocumentElement.SelectSingleNode("NFFT").InnerText, culture);
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ImageWidth = Convert.ToInt32(doc.DocumentElement.SelectSingleNode("ImageWidth").InnerText, culture);
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SampleDuration = Convert.ToDouble(doc.DocumentElement.SelectSingleNode("SampleDuration").InnerText, culture);
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var images = new List<Bitmap>();
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var fileNames = Enumerable.Range(0, int.MaxValue)
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.Select(n => Path.Combine(directory, n + ".gif"))
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.TakeWhile(p => File.Exists(p));
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foreach (string fileName in fileNames)
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{
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// important that this does not lock file (do NOT use Image.FromFile(fileName) or alike!!!)
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using (var ms = new MemoryStream(File.ReadAllBytes(fileName)))
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{
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images.Add((Bitmap)Image.FromStream(ms));
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}
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}
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Images = images;
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}
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catch
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{
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}
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}
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public void Dispose()
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{
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foreach (var image in Images)
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{
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try
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{
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image.Dispose();
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}
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catch
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{
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}
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}
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Images = new Bitmap[0];
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}
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public static SpectrogramData FromDisk(string spectrogramDirectory)
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{
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return new SpectrogramData(spectrogramDirectory);
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}
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}
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public class WavePeakGenerator : IDisposable
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{
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public static string GetPeakWaveFileName(string videoFileName)
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{
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var dir = Configuration.WaveformsFolder.TrimEnd(Path.DirectorySeparatorChar);
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if (!Directory.Exists(dir))
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Directory.CreateDirectory(dir);
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var file = new FileInfo(videoFileName);
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var wavePeakName = Utilities.Sha256Hash(file.Name + file.Length + file.CreationTimeUtc.ToShortDateString()) + ".wav";
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wavePeakName = wavePeakName.Replace("=", string.Empty).Replace("/", string.Empty).Replace(",", string.Empty).Replace("?", string.Empty).Replace("*", string.Empty).Replace("+", string.Empty).Replace("\\", string.Empty);
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wavePeakName = Path.Combine(dir, wavePeakName);
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return wavePeakName;
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}
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public static bool IsFileValidForVisualizer(string fileName)
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{
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if (!fileName.EndsWith(".wav", StringComparison.OrdinalIgnoreCase))
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return false;
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using (var wpg = new WavePeakGenerator(fileName))
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{
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return wpg.IsSupported;
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}
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}
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private Stream _stream;
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private WaveHeader _header;
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private delegate int ReadSampleDataValue(byte[] data, ref int index);
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private delegate void WriteSampleDataValue(byte[] buffer, int offset, int value);
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/// <summary>
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/// Constructor
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/// </summary>
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/// <param name="fileName">Wave file name</param>
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public WavePeakGenerator(string fileName)
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: this(new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
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{
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}
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/// <summary>
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/// Constructor
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/// </summary>
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/// <param name="stream">Stream of a wave file</param>
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public WavePeakGenerator(Stream stream)
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{
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_stream = stream;
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_header = new WaveHeader(_stream);
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}
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/// <summary>
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/// Returns true if the current wave file can be processed. Compressed wave files are not supported.
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/// </summary>
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public bool IsSupported
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{
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get
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{
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return _header.AudioFormat == WaveHeader.AudioFormatPcm && _header.Format == "WAVE";
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}
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}
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/// <summary>
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/// Generates peaks and saves them to disk.
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/// </summary>
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/// <param name="delayInMilliseconds">Delay in milliseconds (normally zero)</param>
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/// <param name="peakFileName">Path of the output file</param>
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public WavePeakData GeneratePeaks(int delayInMilliseconds, string peakFileName)
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{
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int peaksPerSecond = Math.Min(Configuration.Settings.VideoControls.WaveformMinimumSampleRate, _header.SampleRate);
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// ensure that peaks per second is a factor of the sample rate
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while (_header.SampleRate % peaksPerSecond != 0)
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peaksPerSecond++;
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int delaySampleCount = (int)(_header.SampleRate * (delayInMilliseconds / TimeCode.BaseUnit));
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// ignore negative delays for now (pretty sure it can't happen in mkv and some places pass in -1 by mistake)
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delaySampleCount = Math.Max(delaySampleCount, 0);
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var peaks = new List<WavePeak>();
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var readSampleDataValue = GetSampleDataReader();
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float sampleAndChannelScale = (float)GetSampleAndChannelScale();
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long fileSampleCount = _header.LengthInSamples;
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long fileSampleOffset = -delaySampleCount;
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int chunkSampleCount = _header.SampleRate / peaksPerSecond;
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byte[] data = new byte[chunkSampleCount * _header.BlockAlign];
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float[] chunkSamples = new float[chunkSampleCount];
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_stream.Seek(_header.DataStartPosition, SeekOrigin.Begin);
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// for negative delays, skip samples at the beginning
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if (fileSampleOffset > 0)
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{
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_stream.Seek(fileSampleOffset * _header.BlockAlign, SeekOrigin.Current);
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}
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while (fileSampleOffset < fileSampleCount)
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{
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// calculate how many samples to skip at the beginning (for positive delays)
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int startSkipSampleCount = 0;
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if (fileSampleOffset < 0)
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{
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startSkipSampleCount = (int)Math.Min(-fileSampleOffset, chunkSampleCount);
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fileSampleOffset += startSkipSampleCount;
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}
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// calculate how many samples to read from the file
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long fileSamplesRemaining = fileSampleCount - Math.Max(fileSampleOffset, 0);
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int fileReadSampleCount = (int)Math.Min(fileSamplesRemaining, chunkSampleCount - startSkipSampleCount);
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// read samples from the file
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if (fileReadSampleCount > 0)
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{
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int fileReadByteCount = fileReadSampleCount * _header.BlockAlign;
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_stream.Read(data, 0, fileReadByteCount);
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fileSampleOffset += fileReadSampleCount;
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int chunkSampleOffset = 0;
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int dataByteOffset = 0;
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while (dataByteOffset < fileReadByteCount)
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{
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float value = 0F;
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for (int iChannel = 0; iChannel < _header.NumberOfChannels; iChannel++)
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{
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value += readSampleDataValue(data, ref dataByteOffset);
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}
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chunkSamples[chunkSampleOffset] = value * sampleAndChannelScale;
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chunkSampleOffset += 1;
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}
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}
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// calculate peaks
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peaks.Add(CalculatePeak(chunkSamples, fileReadSampleCount));
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}
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// save results to file
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using (var stream = File.Create(peakFileName))
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{
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WaveHeader.WriteHeader(stream, peaksPerSecond, 2, 16, peaks.Count);
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byte[] buffer = new byte[4];
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foreach (var peak in peaks)
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{
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WriteValue16Bit(buffer, 0, peak.Max);
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WriteValue16Bit(buffer, 2, peak.Min);
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stream.Write(buffer, 0, 4);
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}
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}
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return new WavePeakData(peaksPerSecond, peaks);
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}
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private static WavePeak CalculatePeak(float[] chunk, int count)
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{
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if (count == 0)
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return new WavePeak();
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float max = chunk[0];
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float min = chunk[0];
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for (int i = 1; i < count; i++)
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{
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float value = chunk[i];
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if (value > max)
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max = value;
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if (value < min)
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min = value;
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}
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return new WavePeak((short)(short.MaxValue * max), (short)(short.MaxValue * min));
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}
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/// <summary>
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/// Loads previously generated peaks from disk.
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/// </summary>
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internal WavePeakData LoadPeaks()
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{
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if (_header.BitsPerSample != 16)
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throw new Exception("Peaks file must be 16 bits per sample.");
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if (_header.NumberOfChannels != 1 && _header.NumberOfChannels != 2)
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throw new Exception("Peaks file must have 1 or 2 channels.");
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// load data
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byte[] data = new byte[_header.DataChunkSize];
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_stream.Position = _header.DataStartPosition;
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_stream.Read(data, 0, data.Length);
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// read peak values
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WavePeak[] peaks = new WavePeak[_header.LengthInSamples];
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int peakIndex = 0;
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if (_header.NumberOfChannels == 2)
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{
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// max value in left channel, min value in right channel
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int byteIndex = 0;
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while (byteIndex < data.Length)
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{
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short max = (short)ReadValue16Bit(data, ref byteIndex);
|
|
short min = (short)ReadValue16Bit(data, ref byteIndex);
|
|
peaks[peakIndex++] = new WavePeak(max, min);
|
|
}
|
|
}
|
|
else if (_header.NumberOfChannels == 1)
|
|
{
|
|
// single sample value (for backwards compatibility)
|
|
int byteIndex = 0;
|
|
while (byteIndex < data.Length)
|
|
{
|
|
short value = (short)ReadValue16Bit(data, ref byteIndex);
|
|
if (value == short.MinValue)
|
|
value = -short.MaxValue;
|
|
value = Math.Abs(value);
|
|
peaks[peakIndex++] = new WavePeak(value, (short)-value);
|
|
}
|
|
}
|
|
|
|
return new WavePeakData(_header.SampleRate, peaks);
|
|
}
|
|
|
|
private static int ReadValue8Bit(byte[] data, ref int index)
|
|
{
|
|
int result = sbyte.MinValue + data[index];
|
|
index += 1;
|
|
return result;
|
|
}
|
|
|
|
private static int ReadValue16Bit(byte[] data, ref int index)
|
|
{
|
|
int result = (short)
|
|
((data[index]) |
|
|
(data[index + 1] << 8));
|
|
index += 2;
|
|
return result;
|
|
}
|
|
|
|
private static int ReadValue24Bit(byte[] data, ref int index)
|
|
{
|
|
int result =
|
|
((data[index] << 8) |
|
|
(data[index + 1] << 16) |
|
|
(data[index + 2] << 24)) >> 8;
|
|
index += 3;
|
|
return result;
|
|
}
|
|
|
|
private static int ReadValue32Bit(byte[] data, ref int index)
|
|
{
|
|
int result =
|
|
(data[index]) |
|
|
(data[index + 1] << 8) |
|
|
(data[index + 2] << 16) |
|
|
(data[index + 3] << 24);
|
|
index += 4;
|
|
return result;
|
|
}
|
|
|
|
private static void WriteValue8Bit(byte[] buffer, int offset, int value)
|
|
{
|
|
buffer[offset] = (byte)(value - sbyte.MinValue);
|
|
}
|
|
|
|
private static void WriteValue16Bit(byte[] buffer, int offset, int value)
|
|
{
|
|
buffer[offset] = (byte)value;
|
|
buffer[offset + 1] = (byte)(value >> 8);
|
|
}
|
|
|
|
private static void WriteValue24Bit(byte[] buffer, int offset, int value)
|
|
{
|
|
buffer[offset] = (byte)value;
|
|
buffer[offset + 1] = (byte)(value >> 8);
|
|
buffer[offset + 2] = (byte)(value >> 16);
|
|
}
|
|
|
|
private static void WriteValue32Bit(byte[] buffer, int offset, int value)
|
|
{
|
|
buffer[offset] = (byte)value;
|
|
buffer[offset + 1] = (byte)(value >> 8);
|
|
buffer[offset + 2] = (byte)(value >> 16);
|
|
buffer[offset + 3] = (byte)(value >> 24);
|
|
}
|
|
|
|
private double GetSampleScale()
|
|
{
|
|
return (1.0 / Math.Pow(2.0, _header.BytesPerSample * 8 - 1));
|
|
}
|
|
|
|
private double GetSampleAndChannelScale()
|
|
{
|
|
return GetSampleScale() / _header.NumberOfChannels;
|
|
}
|
|
|
|
private ReadSampleDataValue GetSampleDataReader()
|
|
{
|
|
switch (_header.BytesPerSample)
|
|
{
|
|
case 1:
|
|
return ReadValue8Bit;
|
|
case 2:
|
|
return ReadValue16Bit;
|
|
case 3:
|
|
return ReadValue24Bit;
|
|
case 4:
|
|
return ReadValue32Bit;
|
|
default:
|
|
throw new InvalidDataException("Cannot read bits per sample of " + _header.BitsPerSample);
|
|
}
|
|
}
|
|
|
|
private WriteSampleDataValue GetSampleDataWriter()
|
|
{
|
|
switch (_header.BytesPerSample)
|
|
{
|
|
case 1:
|
|
return WriteValue8Bit;
|
|
case 2:
|
|
return WriteValue16Bit;
|
|
case 3:
|
|
return WriteValue24Bit;
|
|
case 4:
|
|
return WriteValue32Bit;
|
|
default:
|
|
throw new InvalidDataException("Cannot write bits per sample of " + _header.BitsPerSample);
|
|
}
|
|
}
|
|
|
|
public void Dispose()
|
|
{
|
|
Close();
|
|
}
|
|
|
|
public void Close()
|
|
{
|
|
if (_stream != null)
|
|
_stream.Close();
|
|
}
|
|
|
|
//////////////////////////////////////// SPECTRUM ///////////////////////////////////////////////////////////
|
|
|
|
public SpectrogramData GenerateSpectrogram(int delayInMilliseconds, string spectrogramDirectory)
|
|
{
|
|
const int fftSize = 256; // image height = fft size / 2
|
|
const int imageWidth = 1024;
|
|
|
|
int delaySampleCount = (int)(_header.SampleRate * (delayInMilliseconds / TimeCode.BaseUnit));
|
|
|
|
// ignore negative delays for now (pretty sure it can't happen in mkv and some places pass in -1 by mistake)
|
|
delaySampleCount = Math.Max(delaySampleCount, 0);
|
|
|
|
var images = new List<Bitmap>();
|
|
var drawer = new SpectrogramDrawer(fftSize);
|
|
var readSampleDataValue = GetSampleDataReader();
|
|
Task saveImageTask = null;
|
|
double sampleAndChannelScale = GetSampleAndChannelScale();
|
|
long fileSampleCount = _header.LengthInSamples;
|
|
long fileSampleOffset = -delaySampleCount;
|
|
int chunkSampleCount = fftSize * imageWidth;
|
|
int chunkCount = (int)Math.Ceiling((double)(fileSampleCount + delaySampleCount) / chunkSampleCount);
|
|
byte[] data = new byte[chunkSampleCount * _header.BlockAlign];
|
|
double[] chunkSamples = new double[chunkSampleCount];
|
|
|
|
Directory.CreateDirectory(spectrogramDirectory);
|
|
|
|
_stream.Seek(_header.DataStartPosition, SeekOrigin.Begin);
|
|
|
|
// for negative delays, skip samples at the beginning
|
|
if (fileSampleOffset > 0)
|
|
{
|
|
_stream.Seek(fileSampleOffset * _header.BlockAlign, SeekOrigin.Current);
|
|
}
|
|
|
|
for (int iChunk = 0; iChunk < chunkCount; iChunk++)
|
|
{
|
|
// calculate padding at the beginning (for positive delays)
|
|
int startPaddingSampleCount = 0;
|
|
if (fileSampleOffset < 0)
|
|
{
|
|
startPaddingSampleCount = (int)Math.Min(-fileSampleOffset, chunkSampleCount);
|
|
fileSampleOffset += startPaddingSampleCount;
|
|
}
|
|
|
|
// calculate how many samples to read from the file
|
|
long fileSamplesRemaining = fileSampleCount - Math.Max(fileSampleOffset, 0);
|
|
int fileReadSampleCount = (int)Math.Min(fileSamplesRemaining, chunkSampleCount - startPaddingSampleCount);
|
|
|
|
// calculate padding at the end (when the data isn't an even multiple of our chunk size)
|
|
int endPaddingSampleCount = chunkSampleCount - startPaddingSampleCount - fileReadSampleCount;
|
|
|
|
int chunkSampleOffset = 0;
|
|
|
|
// add padding at the beginning
|
|
if (startPaddingSampleCount > 0)
|
|
{
|
|
Array.Clear(chunkSamples, chunkSampleOffset, startPaddingSampleCount);
|
|
chunkSampleOffset += startPaddingSampleCount;
|
|
}
|
|
|
|
// read samples from the file
|
|
if (fileReadSampleCount > 0)
|
|
{
|
|
int fileReadByteCount = fileReadSampleCount * _header.BlockAlign;
|
|
_stream.Read(data, 0, fileReadByteCount);
|
|
fileSampleOffset += fileReadSampleCount;
|
|
|
|
int dataByteOffset = 0;
|
|
while (dataByteOffset < fileReadByteCount)
|
|
{
|
|
double value = 0D;
|
|
for (int iChannel = 0; iChannel < _header.NumberOfChannels; iChannel++)
|
|
{
|
|
value += readSampleDataValue(data, ref dataByteOffset);
|
|
}
|
|
chunkSamples[chunkSampleOffset] = value * sampleAndChannelScale;
|
|
chunkSampleOffset += 1;
|
|
}
|
|
}
|
|
|
|
// add padding at the end
|
|
if (endPaddingSampleCount > 0)
|
|
{
|
|
Array.Clear(chunkSamples, chunkSampleOffset, endPaddingSampleCount);
|
|
chunkSampleOffset += endPaddingSampleCount;
|
|
}
|
|
|
|
// generate spectrogram for this chunk
|
|
Bitmap bmp = drawer.Draw(chunkSamples);
|
|
images.Add(bmp);
|
|
|
|
// wait for previous image to finish saving
|
|
if (saveImageTask != null)
|
|
saveImageTask.Wait();
|
|
|
|
// save image
|
|
string imagePath = Path.Combine(spectrogramDirectory, iChunk + ".gif");
|
|
saveImageTask = Task.Factory.StartNew(() =>
|
|
{
|
|
bmp.Save(imagePath, System.Drawing.Imaging.ImageFormat.Gif);
|
|
});
|
|
}
|
|
|
|
// wait for last image to finish saving
|
|
if (saveImageTask != null)
|
|
saveImageTask.Wait();
|
|
|
|
var doc = new XmlDocument();
|
|
var culture = CultureInfo.InvariantCulture;
|
|
double sampleDuration = (double)fftSize / _header.SampleRate;
|
|
doc.LoadXml("<SpectrogramInfo><SampleDuration/><NFFT/><ImageWidth/><SecondsPerImage/></SpectrogramInfo>");
|
|
doc.DocumentElement.SelectSingleNode("SampleDuration").InnerText = sampleDuration.ToString(culture);
|
|
doc.DocumentElement.SelectSingleNode("NFFT").InnerText = fftSize.ToString(culture);
|
|
doc.DocumentElement.SelectSingleNode("ImageWidth").InnerText = imageWidth.ToString(culture);
|
|
doc.DocumentElement.SelectSingleNode("SecondsPerImage").InnerText = ((double)chunkSampleCount / _header.SampleRate).ToString(culture); // currently unused; for backwards compatibility
|
|
doc.Save(Path.Combine(spectrogramDirectory, "Info.xml"));
|
|
|
|
return new SpectrogramData(fftSize, imageWidth, sampleDuration, images);
|
|
}
|
|
|
|
public class SpectrogramDrawer
|
|
{
|
|
private const double RaisedCosineWindowScale = 0.5;
|
|
private const int MagnitudeIndexRange = 256;
|
|
|
|
private readonly int _nfft;
|
|
private readonly MagnitudeToIndexMapper _mapper;
|
|
private readonly RealFFT _fft;
|
|
private readonly FastBitmap.PixelData[] _palette;
|
|
private readonly double[] _segment;
|
|
private readonly double[] _window;
|
|
private readonly double[] _magnitude1;
|
|
private readonly double[] _magnitude2;
|
|
|
|
public static string GetSpectrogramFolder(string videoFileName)
|
|
{
|
|
var dir = Configuration.SpectrogramsFolder.TrimEnd(Path.DirectorySeparatorChar);
|
|
if (!Directory.Exists(dir))
|
|
Directory.CreateDirectory(dir);
|
|
|
|
var file = new FileInfo(videoFileName);
|
|
var name = Utilities.Sha256Hash(file.Name + file.Length + file.CreationTimeUtc.ToShortDateString());
|
|
name = name.Replace("=", string.Empty).Replace("/", string.Empty).Replace(",", string.Empty).Replace("?", string.Empty).Replace("*", string.Empty).Replace("+", string.Empty).Replace("\\", string.Empty);
|
|
name = Path.Combine(dir, name);
|
|
return name;
|
|
}
|
|
|
|
public SpectrogramDrawer(int nfft)
|
|
{
|
|
_nfft = nfft;
|
|
_mapper = new MagnitudeToIndexMapper(100.0, MagnitudeIndexRange - 1);
|
|
_fft = new RealFFT(nfft);
|
|
_palette = GeneratePalette();
|
|
_segment = new double[nfft];
|
|
_window = CreateRaisedCosineWindow(nfft);
|
|
_magnitude1 = new double[nfft / 2];
|
|
_magnitude2 = 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)
|
|
{
|
|
int width = samples.Length / _nfft;
|
|
int height = _nfft / 2;
|
|
var bmp = new FastBitmap(new Bitmap(width, height));
|
|
bmp.LockImage();
|
|
for (int x = 0; x < width; x++)
|
|
{
|
|
// process 2 segments offset by -1/4 and 1/4 fft size, resulting in 1/2 fft size
|
|
// window spacing (the minimum overlap to avoid discarding parts of the signal)
|
|
ProcessSegment(samples, (x * _nfft) - (x > 0 ? _nfft / 4 : 0), _magnitude1);
|
|
ProcessSegment(samples, (x * _nfft) + (x < width - 1 ? _nfft / 4 : 0), _magnitude2);
|
|
|
|
// draw
|
|
for (int y = 0; y < height; y++)
|
|
{
|
|
int colorIndex = _mapper.Map((_magnitude1[y] + _magnitude2[y]) / 2.0);
|
|
bmp.SetPixel(x, height - y - 1, _palette[colorIndex]);
|
|
}
|
|
}
|
|
bmp.UnlockImage();
|
|
return bmp.GetBitmap();
|
|
}
|
|
|
|
private void ProcessSegment(double[] samples, int offset, double[] magnitude)
|
|
{
|
|
// read a segment of the recorded signal
|
|
for (int i = 0; i < _nfft; i++)
|
|
_segment[i] = samples[offset + i] * _window[i];
|
|
|
|
// transform to the frequency domain
|
|
_fft.ComputeForward(_segment);
|
|
|
|
// compute the magnitude of the spectrum
|
|
MagnitudeSpectrum(_segment, magnitude);
|
|
}
|
|
|
|
private static double[] CreateRaisedCosineWindow(int n)
|
|
{
|
|
double twoPiOverN = Math.PI * 2.0 / n;
|
|
double[] dst = new double[n];
|
|
for (int i = 0; i < n; i++)
|
|
dst[i] = 0.5 * (1.0 - Math.Cos(twoPiOverN * i));
|
|
return dst;
|
|
}
|
|
|
|
private static void MagnitudeSpectrum(double[] segment, double[] magnitude)
|
|
{
|
|
magnitude[0] = Math.Sqrt(SquareSum(segment[0], segment[1]));
|
|
for (int i = 2; i < segment.Length; i += 2)
|
|
magnitude[i / 2] = Math.Sqrt(SquareSum(segment[i], segment[i + 1]) * 2.0);
|
|
}
|
|
|
|
private static double SquareSum(double a, double b)
|
|
{
|
|
return a * a + b * b;
|
|
}
|
|
|
|
private static FastBitmap.PixelData[] GeneratePalette()
|
|
{
|
|
var palette = new FastBitmap.PixelData[MagnitudeIndexRange];
|
|
if (Configuration.Settings.VideoControls.SpectrogramAppearance == "Classic")
|
|
{
|
|
for (int colorIndex = 0; colorIndex < MagnitudeIndexRange; colorIndex++)
|
|
palette[colorIndex] = new FastBitmap.PixelData(PaletteValue(colorIndex, MagnitudeIndexRange));
|
|
}
|
|
else
|
|
{
|
|
var list = SmoothColors(0, 0, 0, Configuration.Settings.VideoControls.WaveformColor.R,
|
|
Configuration.Settings.VideoControls.WaveformColor.G,
|
|
Configuration.Settings.VideoControls.WaveformColor.B, MagnitudeIndexRange);
|
|
for (int i = 0; i < MagnitudeIndexRange; i++)
|
|
palette[i] = new FastBitmap.PixelData(list[i]);
|
|
}
|
|
return palette;
|
|
}
|
|
|
|
private static Color PaletteValue(int x, int range)
|
|
{
|
|
double g;
|
|
double r;
|
|
double b;
|
|
|
|
double r4 = range / 4.0;
|
|
const double u = 255;
|
|
|
|
if (x < r4)
|
|
{
|
|
b = x / r4;
|
|
g = 0;
|
|
r = 0;
|
|
}
|
|
else if (x < 2 * r4)
|
|
{
|
|
b = (1 - (x - r4) / r4);
|
|
g = 1 - b;
|
|
r = 0;
|
|
}
|
|
else if (x < 3 * r4)
|
|
{
|
|
b = 0;
|
|
g = (2 - (x - r4) / r4);
|
|
r = 1 - g;
|
|
}
|
|
else
|
|
{
|
|
b = (x - 3 * r4) / r4;
|
|
g = 0;
|
|
r = 1 - b;
|
|
}
|
|
|
|
r = ((int)(Math.Sqrt(r) * u)) & 0xff;
|
|
g = ((int)(Math.Sqrt(g) * u)) & 0xff;
|
|
b = ((int)(Math.Sqrt(b) * u)) & 0xff;
|
|
|
|
return Color.FromArgb((int)r, (int)g, (int)b);
|
|
}
|
|
|
|
private static List<Color> SmoothColors(int fromR, int fromG, int fromB, int toR, int toG, int toB, int count)
|
|
{
|
|
while (toR < 255 && toG < 255 && toB < 255)
|
|
{
|
|
toR++;
|
|
toG++;
|
|
toB++;
|
|
}
|
|
|
|
var list = new List<Color>();
|
|
double r = fromR;
|
|
double g = fromG;
|
|
double b = fromB;
|
|
double diffR = (toR - fromR) / (double)count;
|
|
double diffG = (toG - fromG) / (double)count;
|
|
double diffB = (toB - fromB) / (double)count;
|
|
|
|
for (int i = 0; i < count; i++)
|
|
{
|
|
list.Add(Color.FromArgb((int)r, (int)g, (int)b));
|
|
r += diffR;
|
|
g += diffG;
|
|
b += diffB;
|
|
}
|
|
return list;
|
|
}
|
|
|
|
/// Maps magnitudes in the range [-decibelRange .. 0] dB to palette index values in the range [0 .. indexMax]
|
|
private class MagnitudeToIndexMapper
|
|
{
|
|
private readonly double _minMagnitude;
|
|
private readonly double _multiplier;
|
|
private readonly double _addend;
|
|
|
|
public MagnitudeToIndexMapper(double decibelRange, int indexMax)
|
|
{
|
|
double mappingScale = indexMax / decibelRange;
|
|
_minMagnitude = Math.Pow(10.0, -decibelRange / 20.0);
|
|
_multiplier = 20.0 * mappingScale;
|
|
_addend = decibelRange * mappingScale;
|
|
}
|
|
|
|
public int Map(double magnitude)
|
|
{
|
|
return magnitude >= _minMagnitude ? (int)(Math.Log10(magnitude) * _multiplier + _addend) : 0;
|
|
}
|
|
|
|
// Less optimized but readable version of the above
|
|
public static int Map(double magnitude, double decibelRange, int indexMax)
|
|
{
|
|
if (magnitude == 0) return 0;
|
|
double decibelLevel = 20.0 * Math.Log10(magnitude);
|
|
return decibelLevel >= -decibelRange ? (int)(indexMax * (decibelLevel + decibelRange) / decibelRange) : 0;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|