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Moved OSL/IMA/BGM compression out of BGMDataFormat into its own compression module

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This commit is contained in:
Michael Becker 2014-04-17 16:10:19 -04:00
parent ab84297edc
commit f4f7eddc07
2 changed files with 101 additions and 73 deletions
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77
CSharp/Plugins/UniversalEditor.Plugins.OSLib/DataFormats/Multimedia/Audio/BGM/BGMDataFormat.cs
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@ -37,10 +37,12 @@ namespace UniversalEditor.DataFormats.Multimedia.Audio.BGM
byte unknown2 = reader.ReadByte();
byte[] sampleData = reader.ReadToEnd();
short[] usamples = OSLDecode(sampleData.Length / 2, sampleData);
OSLCompressionModule ocm = new OSLCompressionModule();
sampleData = ocm.Decompress(sampleData);
WaveformAudioObjectModel wave = (objectModel as WaveformAudioObjectModel);
wave.RawSamples = usamples;
wave.RawData = sampleData;
wave.Header.BitsPerSample = 16;
wave.Header.ChannelCount = 1;
wave.Header.SampleRate = sampleRate;
@ -48,77 +50,6 @@ namespace UniversalEditor.DataFormats.Multimedia.Audio.BGM
wave.Header.DataRate = sampleRate * 2;
}
private readonly sbyte[] ima_index_table /*[16]*/ =
{
-1, -1, -1, -1, 2, 4, 7, 12,
-1, -1, -1, -1, 2, 4, 7, 12
};
private readonly short[] ima_step_table /*[89]*/ =
{
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
5894, 6484, 7132, 7845, 8630, 9493,10442,11487,12635,13899,
15289,16818,18500,20350,22385,24623,27086,29794,32767
};
private static int ima_get_diff(int step, byte nibble, ref int predictor)
{
int diff = step >> 3;
if ((nibble & 1) != 0) diff += step >> 2;
if ((nibble & 2) != 0) diff += step >> 1;
if ((nibble & 4) != 0) diff += step;
if ((nibble & 7) == 7) diff += step >> 1;
if ((nibble & 8) != 0) diff = -diff;
return diff;
}
private short[] OSLDecode(int sampleCount, byte[] data)
{
// each byte represents two IMA nibbles, which each represent a signed 16-bit PCM sample
// so therefore each byte represents 2 Int16 samples
short[] samples = new short[data.Length * 2];
int len = data.Length;
int predictor = 0;
int step_index = 0;
byte nibble = 0;
for (int i = 0; i < data.Length; i++)
{
int step = 0;
nibble = (byte)(data[i] & 0x0F);
ima_process_nibble(nibble, ref step_index, ref predictor, ref step);
samples[(int)((double)i * 2)] = (short)predictor;
nibble = (byte)(data[i] >> 4);
ima_process_nibble(nibble, ref step_index, ref predictor, ref step);
samples[(int)((double)i * 2) + 1] = (short)predictor;
}
return samples;
}
private void ima_process_nibble(byte nibble, ref int step_index, ref int predictor, ref int step)
{
if (step_index < 0) step_index = 0;
if (step_index > ima_step_table.Length - 1) step_index = ima_step_table.Length - 1;
step = ima_step_table[step_index];
int diff = ima_get_diff(step, nibble, ref predictor);
step_index += ima_index_table[nibble & 0x07];
predictor = predictor + diff;
if (predictor < Int16.MinValue) predictor = Int16.MinValue;
if (predictor > Int16.MaxValue) predictor = Int16.MaxValue;
}
protected override void SaveInternal(ObjectModel objectModel)
{
throw new NotImplementedException();

97
CSharp/Plugins/UniversalEditor.Plugins.OSLib/DataFormats/Multimedia/Audio/BGM/OSLCompressionModule.cs Normal file
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@ -0,0 +1,97 @@
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UniversalEditor.Accessors;
using UniversalEditor.Compression;
using UniversalEditor.IO;
namespace UniversalEditor.DataFormats.Multimedia.Audio.BGM
{
public class OSLCompressionModule : CompressionModule
{
public override string Name
{
get { return "oslbgm"; }
}
private readonly sbyte[] ima_index_table /*[16]*/ =
{
-1, -1, -1, -1, 2, 4, 7, 12,
-1, -1, -1, -1, 2, 4, 7, 12
};
private readonly short[] ima_step_table /*[89]*/ =
{
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
5894, 6484, 7132, 7845, 8630, 9493,10442,11487,12635,13899,
15289,16818,18500,20350,22385,24623,27086,29794,32767
};
private static int ima_get_diff(int step, byte nibble, ref int predictor)
{
int diff = step >> 3;
if ((nibble & 1) != 0) diff += step >> 2;
if ((nibble & 2) != 0) diff += step >> 1;
if ((nibble & 4) != 0) diff += step;
if ((nibble & 7) == 7) diff += step >> 1;
if ((nibble & 8) != 0) diff = -diff;
return diff;
}
private void ima_process_nibble(byte nibble, ref int step_index, ref int predictor, ref int step)
{
if (step_index < 0) step_index = 0;
if (step_index > ima_step_table.Length - 1) step_index = ima_step_table.Length - 1;
step = ima_step_table[step_index];
int diff = ima_get_diff(step, nibble, ref predictor);
step_index += ima_index_table[nibble & 0x07];
predictor = predictor + diff;
if (predictor < Int16.MinValue) predictor = Int16.MinValue;
if (predictor > Int16.MaxValue) predictor = Int16.MaxValue;
}
protected override void CompressInternal(System.IO.Stream inputStream, System.IO.Stream outputStream)
{
}
protected override void DecompressInternal(System.IO.Stream inputStream, System.IO.Stream outputStream, int inputLength, int outputLength)
{
StreamAccessor saInput = new StreamAccessor(inputStream);
StreamAccessor saOutput = new StreamAccessor(outputStream);
Reader br = new Reader(saInput);
Writer bw = new Writer(saOutput);
// each byte represents two IMA nibbles, which each represent a signed 16-bit PCM sample
// so therefore each byte represents 2 Int16 samples
int predictor = 0;
int step_index = 0;
byte nibble = 0;
while (!br.EndOfStream)
{
byte next = br.ReadByte();
int step = 0;
nibble = (byte)(next & 0x0F);
ima_process_nibble(nibble, ref step_index, ref predictor, ref step);
bw.WriteInt16((short)predictor);
nibble = (byte)(next >> 4);
ima_process_nibble(nibble, ref step_index, ref predictor, ref step);
bw.WriteInt16((short)predictor);
}
}
}
}