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docs/Commodore/WAV.TXT

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Added information about commodore formats
2015-03-25 02:19:24 +00:00
*** WAV (RIFF audio files) Resource Interchange File Format
*** Document revision: 1.1
*** Last updated: March 11, 2004
*** Compiler/Editor: Peter Schepers
*** Contributors/sources: Various net documents
The WAV file is a variant of the RIFF format, specifically used for
audio. RIFF is a generic format used mainly for video (AVI) and audio. It
is built up with "chunks" which contain a chunk ID and a chunk size.
Below is a dump of a sample WAV file showing the header.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
0000: 52 49 46 46 D4 45 CC 01 57 41 56 45 66 6D 74 20 RIFF<46>E<EFBFBD><45>WAVEfmt<6D>
0010: 10 00 00 00 01 00 02 00 44 AC 00 00 10 B1 02 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>D<EFBFBD><44><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0020: 04 00 10 00 64 61 74 61 B0 45 CC 01 95 00 6D FF <20><><EFBFBD><EFBFBD>data<74>E<EFBFBD><45><EFBFBD><EFBFBD>m<EFBFBD>
0030: 97 00 77 FF 6E 00 25 FF 58 00 14 FF 75 00 ED FE <20><>w<EFBFBD>n<EFBFBD>%<25>X<EFBFBD><58><EFBFBD>u<EFBFBD><75><EFBFBD>
0040: 62 00 33 FE 2C 00 07 FE C4 FF 7A FE 53 FF C3 FE b<>3<EFBFBD>,<2C><><EFBFBD><EFBFBD><EFBFBD>z<EFBFBD>S<EFBFBD><53><EFBFBD>
0050: 91 FF 83 FE 21 00 91 FE EB 00 0D FF FF 00 57 FF <20><><EFBFBD><EFBFBD>!<21><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>W<EFBFBD>
0060: 98 00 C4 FF 9F 00 79 00 60 00 DD 00 07 00 1D 01 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>y<EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
$0000-0003: Chunk ID "RIFF" in ASCII ("RIFX" files identify the
samples audio data in hi/lo format instead of the normal
lo/hi format)
0004-0007: Chunk size (lo/hi) $01CC45D4=30,164,452 is the total size
minus 8 (these first 8 bytes are not included in the
overall size)
0008-000B: Chunk format "WAVE". This format requires two subchunks to
exist, "fmt " and "data".
000C-000F: Subchunk1 ID "fmt ". This describes the format of the next
DATA subchunk.
0010-0013: Subchunk size (lo/hi) $00000010 (usually this value for
PCM audio)
0014-0015: Audio format (1=PCM, 2 and higher are custom) ($0001)
- $0001 = standard PCM
- $0101 = IBM mu-law (custom)
- $0102 = IBM a-law (custom)
- $0103 = IBM AVC ADPCM (custom)
0016-0017: Number of channels (1=mono, 2=stereo, etc) ($0002)
0018-001B: Sample rate per second (lo/hi) $0000AC44 = 44100
001C-001F: Byte rate per second (=sample rate * number of channels *
(bits per channel/8)) $0002B110 = 176400
0020-0021: Block Align (=number of channels * bits per sample/8)
($0004).
0022-0023: Bits per sample (8=8 bits, 16=16 bits) ($0010). Samples
not using the entire bit range allocated should set the
unused bits off.
0024-0027: Subchunk2 ID "data". This chunk contains the audio
samples. There can be more than one in a WAV file.
0028-002B: Subchunk2 size (lo/hi) ($01CC45B0=30,164,400)
002C-xxxx: Audio data (lo/hi), stored as 2's complimented signed
integers in the following order:
Sample 1: Channel1 (left) ($0095=+149)
Sample 1: Channel2 (right) ($FF6D=-)
Sample 2: Channel1 (left) ($0097=+151)
Sample 2: Channel2 (right) ($FF77=-)
Sample 3: Channel1 (left) ($006E=+110)
Sample 3: Channel2 (right) ($FF25=-)
Notes: 8-bit samples are stored as unsigned chars, with values ranging
ranging from 0-255. 16-bit samples are stored as signed integers,
with values ranging from -32768 to 32767
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
2D402C: 4C 49 53 54 40 00 00 00 49 4E 46 4F 49 53 46 54 LIST@<40><><EFBFBD>INFOISFT
2D403C: 15 00 00 00 53 6F 6E 79 20 53 6F 75 6E 64 20 46 <20><><EFBFBD><EFBFBD>Sony<6E>Sound<6E>F
2D404C: 6F 72 67 65 20 37 2E 30 00 00 49 45 4E 47 02 00 orge<67>7.0<EFBFBD><EFBFBD>IENG<EFBFBD><EFBFBD>
2D405C: 00 00 20 00 49 43 52 44 0B 00 00 00 32 30 30 33 <20><><EFBFBD><EFBFBD>ICRD<52><44><EFBFBD><EFBFBD>2003
2D406C: 2D 31 30 2D 31 37 00 02 .. .. .. .. .. .. .. .. -10-17<31><37>........
Above is a dump of the end of a WAV file, with the LIST information chunk
shown. The four bytes (40 00 00 00) immediately following the "LIST"
identifier show the size of the LIST chunk, in LO/HI format. In this case,
the chunk size is $00000040, or 64 bytes.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
02F488AC: 63 75 65 20 C4 00 00 00 08 00 00 00 01 00 00 00 cue<75><65><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F488BC: 00 C0 21 00 64 61 74 61 00 00 00 00 00 00 00 00 <20><>!<21>data<74><61><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F488CC: 00 C0 21 00 02 00 00 00 00 40 11 00 64 61 74 61 <20><>!<21><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@<40><>data
02F488DC: 00 00 00 00 00 00 00 00 00 40 11 00 03 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@<40><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F488EC: 00 00 3A 00 64 61 74 61 00 00 00 00 00 00 00 00 <20><>:<3A>data<74><61><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F488FC: 00 00 3A 00 04 00 00 00 00 00 59 00 64 61 74 61 <20><>:<3A><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Y<EFBFBD>data
02F4890C: 00 00 00 00 00 00 00 00 00 00 59 00 05 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Y<EFBFBD><59><EFBFBD><EFBFBD><EFBFBD>
02F4891C: 00 C0 6C 00 64 61 74 61 00 00 00 00 00 00 00 00 <20><>l<EFBFBD>data<74><61><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F4892C: 00 C0 6C 00 06 00 00 00 00 40 84 00 64 61 74 61 <20><>l<EFBFBD><6C><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@<40><>data
02F4893C: 00 00 00 00 00 00 00 00 00 40 84 00 07 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@<40><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F4894C: 00 80 9A 00 64 61 74 61 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD>data<74><61><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
02F4895C: 00 80 9A 00 08 00 00 00 00 00 AC 00 64 61 74 61 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>data
02F4896C: 00 00 00 00 00 00 00 00 00 00 AC 00 4C 49 53 54 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>LIST
02F4897C: 84 00 00 00 61 64 74 6C 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>adtllabl<62><6C><EFBFBD><EFBFBD>
02F4898C: 01 00 00 00 30 31 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>01<30><31>labl<62><6C><EFBFBD><EFBFBD>
02F4899C: 02 00 00 00 30 32 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>02<30><32>labl<62><6C><EFBFBD><EFBFBD>
02F489AC: 03 00 00 00 30 33 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>03<30><33>labl<62><6C><EFBFBD><EFBFBD>
02F489BC: 04 00 00 00 30 34 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>04<30><34>labl<62><6C><EFBFBD><EFBFBD>
02F489CC: 05 00 00 00 30 35 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>05<30><35>labl<62><6C><EFBFBD><EFBFBD>
02F489DC: 06 00 00 00 30 36 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>06<30><36>labl<62><6C><EFBFBD><EFBFBD>
02F489EC: 07 00 00 00 30 37 00 00 6C 61 62 6C 07 00 00 00 <20><><EFBFBD><EFBFBD>07<30><37>labl<62><6C><EFBFBD><EFBFBD>
02F489FC: 08 00 00 00 30 38 00 00 .. .. .. .. .. .. .. .. <20><><EFBFBD><EFBFBD>08<30><38>........
Above is the "cue " chunk layout, also at the end of the WAV. These
describe cue points (or markers) placed in the WAV file.
To analyse a WAV file quickly is very easy:
1. Examine the initial chunk ID (RIFF) and its size. The size should be
the filesize-8.
2. Check for the WAVE chunk ID next. If it's not there then you don't
have a proper WAV file.
3. Now you can start checking the individual sub-chunks. Read in 8
bytes. The first four are the sub-chunk ID and the last four are the
sub-chunk size. If you want to check the contents of the sub-chunk
thats up to you.
4. If you seek forward in the file the size of the sub-chunk you will
find yourself at the next sub-chunk.
WAV files can also have other sub-chunk ID's such as FACT, ASFP and LIST.
I will not get into the specifics of these. There are other more extensive
documents on the web that describe the WAV and RIFF format much better than
I can.
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