GARbro-mirror/ArcFormats/AudioMP3.cs

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2015-05-02 03:33:22 +08:00
//! \file AudioMP3.cs
//! \date Fri May 01 22:04:37 2015
//! \brief MP3 wrapper for GameRes.
//
// Copyright (C) 2015 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using System.ComponentModel.Composition;
using System.IO;
using NAudio.Wave;
namespace GameRes.Formats
{
public class Mp3Input : SoundInput
{
int m_bitrate;
Stream m_source;
public override long Position
{
get { return m_input.Position; }
set { m_input.Position = value; }
}
public override bool CanSeek { get { return m_input.CanSeek; } }
public override int SourceBitrate
{
get { return m_bitrate; }
}
public Mp3Input (Stream file) : base (file)
{
var rdr = new Mp3FileReader (m_input);
var wav = WaveFormatConversionStream.CreatePcmStream (rdr);
var bar = new BlockAlignReductionStream (wav);
m_source = m_input;
m_input = bar;
m_bitrate = rdr.Mp3WaveFormat.AverageBytesPerSecond*8;
var format = new GameRes.WaveFormat();
format.FormatTag = (ushort)wav.WaveFormat.Encoding;
format.Channels = (ushort)wav.WaveFormat.Channels;
format.SamplesPerSecond = (uint)wav.WaveFormat.SampleRate;
format.BitsPerSample = (ushort)wav.WaveFormat.BitsPerSample;
format.BlockAlign = (ushort)bar.BlockAlign;
format.AverageBytesPerSecond = (uint)wav.WaveFormat.AverageBytesPerSecond;
this.Format = format;
this.PcmSize = m_input.Length;
}
public override int Read(byte[] buffer, int offset, int count)
{
return m_input.Read (buffer, offset, count);
}
#region IDisposable Members
protected override void Dispose (bool disposing)
{
if (null != m_source)
{
if (disposing)
{
m_source.Dispose();
}
m_source = null;
base.Dispose (disposing);
}
}
#endregion
}
[Export(typeof(AudioFormat))]
public class Mp3Audio : AudioFormat
{
public override string Tag { get { return "MP3"; } }
public override string Description { get { return "MPEG Layer 3 audio format"; } }
public override uint Signature { get { return 0; } }
public override SoundInput TryOpen (Stream file)
{
byte[] header = new byte[10];
if (header.Length != file.Read (header, 0, header.Length))
return null;
long start_offset = SkipId3Tag (header);
if (0 != start_offset)
{
file.Position = start_offset;
if (4 != file.Read (header, 0, 4))
return null;
}
if (0xff != header[0] || 0xf2 != (header[1] & 0xf6) || 0xf0 == (header[2] & 0xf0))
return null;
file.Position = 0;
return new Mp3Input (file);
}
long SkipId3Tag (byte[] buffer)
{
long start_offset = 0;
if (0x49 == buffer[0] && 0x44 == buffer[1] && 0x33 == buffer[2]) // 'ID3'
{
if (buffer[3] < 0x80 && buffer[4] < 0x80 &&
buffer[6] < 0x80 && buffer[7] < 0x80 && buffer[8] < 0x80 && buffer[9] < 0x80)
{
int size = buffer[6] << 21 | buffer[7] << 14 | buffer[8] << 7 | buffer[9];
if (buffer[3] > 3 && 0 != (buffer[5] & 0x10)) // v2.4 footer present
size += 10;
start_offset = 10 + size;
}
}
return start_offset;
}
}
}