129 строки
4.6 KiB
Plaintext
129 строки
4.6 KiB
Plaintext
WAV File Reference
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Copyright (c) Wiesław Šoltés. All rights reserved.
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Licensed under the MIT license. See LICENSE file in the project root for full license information.
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0. https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
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The canonical WAVE format starts with the RIFF header
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1. http://msdn.microsoft.com/en-us/library/dd757720(v=VS.85).aspx
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typedef struct
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{
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WORD wFormatTag;
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WORD nChannels;
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DWORD nSamplesPerSec;
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DWORD nAvgBytesPerSec;
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WORD nBlockAlign;
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WORD wBitsPerSample;
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WORD cbSize;
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} WAVEFORMATEX;
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Note:
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cbSize is at Least 22
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For WAVEFORMATEXTENSIBLE, cbSize must always be set to at least 22.
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This is the sum of the sizes of the Samples union (2), DWORD dwChannelMask (4), and GUID guidSubFormat (16).
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This is appended to the initial WAVEFORMATEX Format (size 18),
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so a WAVEFORMATPCMEX and WAVEFORMATIEEEFLOATEX structure is 64-bit aligned.
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2. http://msdn.microsoft.com/en-us/library/dd757721(v=VS.85).aspx
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http://www.microsoft.com/whdc/device/audio/multichaud.mspx
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typedef struct
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{
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WAVEFORMATEX Format;
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union
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{
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WORD wValidBitsPerSample;
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WORD wSamplesPerBlock;
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WORD wReserved;
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} Samples;
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DWORD dwChannelMask;
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GUID SubFormat;
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} WAVEFORMATEXTENSIBLE, *PWAVEFORMATEXTENSIBLE;
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3. http://www.microsoft.com/whdc/device/audio/multichaud.mspx
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* KSMEDIA.H
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#define STATIC_KSDATAFORMAT_SUBTYPE_PCM\
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DEFINE_WAVEFORMATEX_GUID(WAVE_FORMAT_PCM)
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DEFINE_GUIDSTRUCT("00000001-0000-0010-8000-00aa00389b71", KSDATAFORMAT_SUBTYPE_PCM);
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#define KSDATAFORMAT_SUBTYPE_PCM DEFINE_GUIDNAMED(KSDATAFORMAT_SUBTYPE_PCM)
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#define STATIC_KSDATAFORMAT_SUBTYPE_IEEE_FLOAT\
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DEFINE_WAVEFORMATEX_GUID(WAVE_FORMAT_IEEE_FLOAT)
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DEFINE_GUIDSTRUCT("00000003-0000-0010-8000-00aa00389b71", KSDATAFORMAT_SUBTYPE_IEEE_FLOAT);
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#define KSDATAFORMAT_SUBTYPE_IEEE_FLOAT DEFINE_GUIDNAMED(KSDATAFORMAT_SUBTYPE_IEEE_FLOAT)
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4. http://www.microsoft.com/whdc/device/audio/multichaud.mspx
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Default Channel Ordering:
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1. Front Left - FL
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2. Front Right - FR
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3. Front Center - FC
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4. Low Frequency - LF
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5. Back Left - BL
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6. Back Right - BR
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7. Front Left of Center - FLC
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8. Front Right of Center - FRC
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9. Back Center - BC
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10. Side Left - SL
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11. Side Right - SR
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12. Top Center - TC
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13. Top Front Left - TFL
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14. Top Front Center - TFC
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15. Top Front Right - TFR
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16. Top Back Left - TBL
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17. Top Back Center - TBC
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18. Top Back Right - TBR
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5. The canonical WAVE format starts with the RIFF header:
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0 4 ChunkID Contains the letters "RIFF" in ASCII form
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(0x52494646 big-endian form).
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4 4 ChunkSize 36 + SubChunk2Size, or more precisely:
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4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
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This is the size of the rest of the chunk
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following this number. This is the size of the
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entire file in bytes minus 8 bytes for the
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two fields not included in this count:
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ChunkID and ChunkSize.
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8 4 Format Contains the letters "WAVE"
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(0x57415645 big-endian form).
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The "WAVE" format consists of two subchunks: "fmt " and "data":
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The "fmt " subchunk describes the sound data's format:
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12 4 Subchunk1ID Contains the letters "fmt "
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(0x666d7420 big-endian form).
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16 4 Subchunk1Size 16 for PCM. This is the size of the
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rest of the Subchunk which follows this number.
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20 2 AudioFormat PCM = 1 (i.e. Linear quantization)
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Values other than 1 indicate some
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form of compression.
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22 2 NumChannels Mono = 1, Stereo = 2, etc.
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24 4 SampleRate 8000, 44100, etc.
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28 4 ByteRate == SampleRate * NumChannels * BitsPerSample/8
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32 2 BlockAlign == NumChannels * BitsPerSample/8
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The number of bytes for one sample including
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all channels. I wonder what happens when
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this number isn't an integer?
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34 2 BitsPerSample 8 bits = 8, 16 bits = 16, etc.
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2 ExtraParamSize if PCM, then doesn't exist
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X ExtraParams space for extra parameters
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The "data" subchunk contains the size of the data and the actual sound:
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36 4 Subchunk2ID Contains the letters "data"
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(0x64617461 big-endian form).
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40 4 Subchunk2Size == NumSamples * NumChannels * BitsPerSample/8
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This is the number of bytes in the data.
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You can also think of this as the size
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of the read of the subchunk following this
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number.
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44 * Data The actual sound data.
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