|
|
| Line 67: |
Line 67: |
| | | |
| Delta=StepTable[lIndexLeft]>>3; | | Delta=StepTable[lIndexLeft]>>3; |
| if (Code & 4) | | if (Code |
| Delta+=StepTable[lIndexLeft];
| |
| if (Code & 2)
| |
| Delta+=StepTable[lIndexLeft]>>1;
| |
| if (Code & 1)
| |
| Delta+=StepTable[lIndexLeft]>>2;
| |
| if (Code & 8) // sign bit
| |
| lCurSampleLeft-=Delta;
| |
| else
| |
| lCurSampleLeft+=Delta;
| |
|
| |
| // clip sample
| |
| if (lCurSampleLeft>32767)
| |
| lCurSampleLeft=32767;
| |
| else if (lCurSampleLeft<-32768)
| |
| lCurSampleLeft=-32768;
| |
|
| |
| lIndexLeft+=IndexAdjust[Code]; // adjust index
| |
|
| |
| // clip index
| |
| if (lIndexLeft<0)
| |
| lIndexLeft=0;
| |
| else if (lIndexLeft>88)
| |
| lIndexLeft=88;
| |
|
| |
| Code=LONIBBLE(Input); // get LOWER 4-bit nibble
| |
|
| |
| Delta=StepTable[lIndexRight]>>3;
| |
| if (Code & 4)
| |
| Delta+=StepTable[lIndexRight];
| |
| if (Code & 2)
| |
| Delta+=StepTable[lIndexRight]>>1;
| |
| if (Code & 1)
| |
| Delta+=StepTable[lIndexRight]>>2;
| |
| if (Code & 8) // sign bit
| |
| lCurSampleRight-=Delta;
| |
| else
| |
| lCurSampleRight+=Delta;
| |
|
| |
| // clip sample
| |
| if (lCurSampleRight>32767)
| |
| lCurSampleRight=32767;
| |
| else if (lCurSampleRight<-32768)
| |
| lCurSampleRight=-32768;
| |
|
| |
| lIndexRight+=IndexAdjust[Code]; // adjust index
| |
|
| |
| // clip index
| |
| if (lIndexRight<0)
| |
| lIndexRight=0;
| |
| else if (lIndexRight>88)
| |
| lIndexRight=88;
| |
|
| |
| // Now we've got lCurSampleLeft and lCurSampleRight which form one stereo
| |
| // sample and all is set for the next input byte...
| |
| Output((SHORT)lCurSampleLeft,(SHORT)lCurSampleRight); // send the sample to output
| |
|
| |
| HINIBBLE and LONIBBLE are higher and lower 4-bit nibbles:
| |
| #define HINIBBLE(byte) ((byte) >> 4)
| |
| #define LONIBBLE(byte) ((byte) & 0x0F)
| |
| Note that depending on your compiler you may need to use additional nibble
| |
| separation in these defines, e.g. ''(((byte) >> 4) & 0x0F)''.
| |
| | |
| StepTable and IndexAdjust are the tables given in the next section of
| |
| this document.
| |
| | |
| Output() is just a placeholder for any action you would like to perform for
| |
| decompressed sample value.
| |
| | |
| Of course, this decompression routine may be greatly optimized.
| |
| | |
| As to mono sound, it's just analoguous:
| |
| | |
| Code=HINIBBLE(Input); // get HIGHER 4-bit nibble
| |
|
| |
| Delta=StepTable[lIndex]>>3;
| |
| if (Code & 4)
| |
| Delta+=StepTable[lIndex];
| |
| if (Code & 2)
| |
| Delta+=StepTable[lIndex]>>1;
| |
| if (Code & 1)
| |
| Delta+=StepTable[lIndex]>>2;
| |
| if (Code & 8) // sign bit
| |
| lCurSample-=Delta;
| |
| else
| |
| lCurSample+=Delta;
| |
|
| |
| // clip sample
| |
| if (lCurSample>32767)
| |
| lCurSample=32767;
| |
| else if (lCurSample<-32768)
| |
| lCurSample=-32768;
| |
|
| |
| lIndex+=IndexAdjust[Code]; // adjust index
| |
|
| |
| // clip index
| |
| if (lIndex<0)
| |
| lIndex=0;
| |
| else if (lIndex>88)
| |
| lIndex=88;
| |
|
| |
| Output((SHORT)lCurSample); // send the sample to output
| |
|
| |
| Code=LONIBBLE(Input); // get LOWER 4-bit nibble
| |
| // ...just the same as above for lower nibble
| |
| | |
| Note that HIGHER nibble is processed first for mono sound and corresponds to
| |
| LEFT channel for stereo.
| |
| | |
| == IMA ADPCM Tables ==
| |
| | |
| LONG IndexAdjust[]=
| |
| {
| |
| -1,
| |
| -1,
| |
| -1,
| |
| -1,
| |
| 2,
| |
| 4,
| |
| 6,
| |
| 8,
| |
| -1,
| |
| -1,
| |
| -1,
| |
| -1,
| |
| 2,
| |
| 4,
| |
| 6,
| |
| 8
| |
| };
| |
|
| |
| LONG StepTable[]=
| |
| {
| |
| 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
| |
| };
| |
| | |
| == HNM Movie Soundtracks ==
| |
| | |
| .HNM movie hasn't got soundtrack inside the HNM movie file itself.
| |
| However the soundtrack for HNM movie is a stand-alone APC file, as a rule,
| |
| with the same file title. The format of such APC soundtracks is just the
| |
| same as described above.
| |
| | |
| == APC Audio Files in BF Archives ==
| |
| | |
| When stored in .BF resources, APC audio files are stored "as is", without
| |
| compression or encryption. That means if you want to play/extract APC
| |
| file from the BF resource you just need to search for (''szID'') id-string
| |
| ("CRYO_APC") and read APC header starting at the beginning position of
| |
| found id-string. This will give you starting point of the file and the size
| |
| of the file will be the sum of APCHeader size and the compressed audio stream
| |
| size correspondent to (''dwOutSize'') header field (that is, (''dwOutSize'') for
| |
| stereo stream and (''dwOutSize)/2'' for mono stream).
| |
| | |
| == ZIK Audio Files ==
| |
| | |
| In the game Chine music is in ZIK files. Most of them are simple RAW files:
| |
| 16-bit signed stereo 22050 Hz (no header), except for only one which is a
| |
| regular WAV file. So, you can just load and play those ZIKs as RAWs (except
| |
| for one which is WAV).
| |
| | |
| ==PC Games Using CRYO APC==
| |
| *[http://www.mobygames.com/game/windows/atlantis-the-lost-tales Atlantis: The Lost Tales]
| |
| *[http://www.mobygames.com/game/windows/sacred-amulet Aztec: The Curse in the Heart of the "City of Gold" a.k.a Sacred Amulet]
| |
| *[http://www.mobygames.com/game/windows/egypt-ii-the-heliopolis-prophecy Egypt II]
| |
| *[http://www.mobygames.com/game/odyssey-the-search-for-ulysses Odyssey: The Search For Ulysses]
| |
| *[http://www.mobygames.com/game/china-the-forbidden-city China: The Forbidden City]
| |
| * Atlantis 2
| |
| * Zero Zone a.k.a Onderzoek 2098 [http://www.mobygames.com/game/windows/zero-zone] [http://en.wikipedia.org/wiki/ZeroZone]
| |
| | |
| [[Category:Game Formats]]
| |
This covers the audio format for one of the versions of CRYO's video formats.
Credit
This file comes from wotsit.org and was originally written by Valery V. Anisimovsky.
APC Audio Files
The music, sfx, speech and video (.HNM) soundtracks in some CRYO Interactive
games are .APC stand-alone files. APC file has the following header:
struct APCHeader
{
char szID[8];
char szVersion[4];
DWORD dwOutSize;
DWORD dwSampleRate;
LONG lSampleLeft;
LONG lSampleRight;
DWORD dwStereo;
};
szID -- ID string, which is "CRYO_APC".
szVersion -- version ID string, all files in the mentioned games have this
set to "1.20". Note that this field may, in principle, vary.
dwOutSize -- number of samples in the file. May be used for song length
(in seconds) calculation.
dwSampleRate -- sample rate for the file.
lSampleLeft -- the initial value for the left sample (see below).
lSampleRight -- the initial value for the right sample (see below).
dwStereo -- this seems to be boolean stereo flag: if this is not zero, the
audio stream in the file is stereo (music and partly video soundtracks),
otherwise it's mono (sfx, speech).
The resolution is NOT specified in the header, so the default value (16-bit)
should be used.
After the APCHeader IMA ADPCM compressed sound data comes. You may find
IMA ADPCM decompression scheme description further in this document.
IMA ADPCM Decompression Algorithm
During the decompression four LONG variables must be maintained for stereo
stream: lIndexLeft, lIndexRight, lCurSampleLeft, lCurSampleRight and two --
for mono stream: lIndex, lCurSample. At the beginning of the file you must
initialize lCurSampleLeft/Right variables to the values from APCHeader while
lIndexLeft/Right are initialized to zeroes.
Note that LONG here is signed.
Here's the code which decompresses one byte of IMA ADPCM compressed
stereo stream. Other bytes are processed in the same way.
BYTE Input; // current byte of compressed data
BYTE Code;
LONG Delta;
Code=HINIBBLE(Input); // get HIGHER 4-bit nibble
Delta=StepTable[lIndexLeft]>>3;
if (Code