ALAC encoder

CUETools.Codecs.ALAC/ALAC.cs

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+/**
+ * CUETools.Codecs.ALAC: pure managed ALAC audio encoder
+ * Copyright (c) 2009 Gregory S. Chudov
+ * Based on ffdshow ALAC audio encoder
+ * Copyright (c) 2008  Jaikrishnan Menon, realityman@gmx.net
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace CUETools.Codecs.ALAC
+{
+	public class Alac
+	{
+		public const int MAX_BLOCKSIZE = 65535;
+		public const int MAX_RICE_PARAM = 14;
+		public const int MAX_PARTITION_ORDER = 8;
+		public const int MAX_PARTITIONS = 1 << MAX_PARTITION_ORDER;
+
+		public const uint UINT32_MAX = 0xffffffff;
+
+		public static StereoMethod LookupStereoMethod(string name)
+		{
+			return (StereoMethod)(Enum.Parse(typeof(StereoMethod), name, true));
+		}
+
+		public static OrderMethod LookupOrderMethod(string name)
+		{
+			return (OrderMethod)(Enum.Parse(typeof(OrderMethod), name, true));
+		}
+
+		public static WindowFunction LookupWindowFunction(string name)
+		{
+			return (WindowFunction)(Enum.Parse(typeof(WindowFunction), name, true));
+		}
+
+	}
+
+	unsafe class RiceContext
+	{
+		public RiceContext()
+		{
+			rparams = new int[Alac.MAX_PARTITIONS];
+			esc_bps = new int[Alac.MAX_PARTITIONS];
+		}
+		/// <summary>
+		/// partition order
+		/// </summary>
+		public int porder;
+
+		/// <summary>
+		/// Rice parameters
+		/// </summary>
+		public int[] rparams;
+
+		/// <summary>
+		/// bps if using escape code
+		/// </summary>
+		public int[] esc_bps;
+	};
+
+	unsafe class ALACSubframe
+	{
+		public ALACSubframe()
+		{
+			rc = new RiceContext();
+			coefs = new int[lpc.MAX_LPC_ORDER];
+		}
+		public int order;
+		public int* residual;
+		public RiceContext rc;
+		public uint size;
+
+		public int ricemodifier;
+		public int cbits;
+		public int shift;
+		public int[] coefs;
+		public int window;
+	};
+
+	unsafe class ALACSubframeInfo
+	{
+		public ALACSubframeInfo()
+		{
+			best = new ALACSubframe();
+			lpc_ctx = new LpcContext[lpc.MAX_LPC_WINDOWS];
+			for (int i = 0; i < lpc.MAX_LPC_WINDOWS; i++)
+				lpc_ctx[i] = new LpcContext();
+		}
+
+		public void Init(int* s, int* r)
+		{
+			samples = s;
+			best.residual = r;
+			best.size = AudioSamples.UINT32_MAX;
+			for (int iWindow = 0; iWindow < lpc.MAX_LPC_WINDOWS; iWindow++)
+				lpc_ctx[iWindow].Reset();
+			done_fixed = 0;
+		}
+
+		public ALACSubframe best;
+		public int* samples;
+		public uint done_fixed;
+		public LpcContext[] lpc_ctx;
+	};
+
+	unsafe class ALACFrame
+	{
+		public ALACFrame(int subframes_count)
+		{
+			subframes = new ALACSubframeInfo[subframes_count];
+			for (int ch = 0; ch < subframes_count; ch++)
+				subframes[ch] = new ALACSubframeInfo();
+			current = new ALACSubframe();
+		}
+
+		public void InitSize(int bs)
+		{
+			blocksize = bs;
+			type = FrameType.Verbatim;
+			interlacing_shift = interlacing_leftweight = 0;
+		}
+
+		public void ChooseBestSubframe(int ch)
+		{
+			if (current.size >= subframes[ch].best.size)
+				return;
+			ALACSubframe tmp = subframes[ch].best;
+			subframes[ch].best = current;
+			current = tmp;
+		}
+
+		public void SwapSubframes(int ch1, int ch2)
+		{
+			ALACSubframeInfo tmp = subframes[ch1];
+			subframes[ch1] = subframes[ch2];
+			subframes[ch2] = tmp;
+		}
+
+		/// <summary>
+		/// Swap subframes according to channel mode.
+		/// It is assumed that we have 4 subframes,
+		/// 0 is right, 1 is left, 2 is middle, 3 is difference
+		/// </summary>
+		public void ChooseSubframes()
+		{
+			if (interlacing_leftweight != 0)
+			{
+				SwapSubframes(1, 3);
+				switch (interlacing_shift)
+				{
+					case 0: // leftside						
+						break;
+					case 1: // midside
+						SwapSubframes(0, 2);
+						break;
+					case 31: // rightside
+						SwapSubframes(0, 4);
+						break;
+				}
+			}
+		}
+
+		public FrameType type;
+		public int blocksize;
+		public int interlacing_shift, interlacing_leftweight;
+		public ALACSubframeInfo[] subframes;
+		public ALACSubframe current;
+		public double* window_buffer;
+	}
+
+	public enum OrderMethod
+	{
+		Max = 0,
+		Estimate = 1,
+		LogFast = 2,
+		LogSearch = 3,
+		EstSearch2 = 4,
+		Search = 5
+	}
+
+	public enum StereoMethod
+	{
+		Independent = 0,
+		Estimate = 1,
+		Estimate2 = 2,
+		Evaluate = 3,
+		Search = 4
+	}
+
+	public enum FrameType
+	{
+		Verbatim = 0,
+		Compressed = 1
+	};
+
+	public enum ChannelMode
+	{
+		NotStereo = 0,
+		LeftRight = 1,
+		LeftSide = 8,
+		RightSide = 9,
+		MidSide = 10
+	}
+
+	public enum WindowFunction
+	{
+		Welch = 1,
+		Tukey = 2,
+		Hann = 4,
+		Flattop = 8,
+		TukFlat = 10
+	}
+}