summaryrefslogtreecommitdiff
path: root/src/client/snd_adpcm.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/client/snd_adpcm.c')
-rw-r--r--src/client/snd_adpcm.c330
1 files changed, 330 insertions, 0 deletions
diff --git a/src/client/snd_adpcm.c b/src/client/snd_adpcm.c
new file mode 100644
index 0000000..89e68f4
--- /dev/null
+++ b/src/client/snd_adpcm.c
@@ -0,0 +1,330 @@
+/***********************************************************
+Copyright 1992 by Stichting Mathematisch Centrum, Amsterdam, The
+Netherlands.
+
+ All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and that
+both that copyright notice and this permission notice appear in
+supporting documentation, and that the names of Stichting Mathematisch
+Centrum or CWI not be used in advertising or publicity pertaining to
+distribution of the software without specific, written prior permission.
+
+STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
+FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+******************************************************************/
+
+/*
+** Intel/DVI ADPCM coder/decoder.
+**
+** The algorithm for this coder was taken from the IMA Compatability Project
+** proceedings, Vol 2, Number 2; May 1992.
+**
+** Version 1.2, 18-Dec-92.
+*/
+
+#include "snd_local.h"
+
+
+/* Intel ADPCM step variation table */
+static int indexTable[16] = {
+ -1, -1, -1, -1, 2, 4, 6, 8,
+ -1, -1, -1, -1, 2, 4, 6, 8,
+};
+
+static int stepsizeTable[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
+};
+
+
+void S_AdpcmEncode( short indata[], char outdata[], int len, struct adpcm_state *state ) {
+ short *inp; /* Input buffer pointer */
+ signed char *outp; /* output buffer pointer */
+ int val; /* Current input sample value */
+ int sign; /* Current adpcm sign bit */
+ int delta; /* Current adpcm output value */
+ int diff; /* Difference between val and sample */
+ int step; /* Stepsize */
+ int valpred; /* Predicted output value */
+ int vpdiff; /* Current change to valpred */
+ int index; /* Current step change index */
+ int outputbuffer; /* place to keep previous 4-bit value */
+ int bufferstep; /* toggle between outputbuffer/output */
+
+ outp = (signed char *)outdata;
+ inp = indata;
+
+ valpred = state->sample;
+ index = state->index;
+ step = stepsizeTable[index];
+
+ outputbuffer = 0; // quiet a compiler warning
+ bufferstep = 1;
+
+ for ( ; len > 0 ; len-- ) {
+ val = *inp++;
+
+ /* Step 1 - compute difference with previous value */
+ diff = val - valpred;
+ sign = (diff < 0) ? 8 : 0;
+ if ( sign ) diff = (-diff);
+
+ /* Step 2 - Divide and clamp */
+ /* Note:
+ ** This code *approximately* computes:
+ ** delta = diff*4/step;
+ ** vpdiff = (delta+0.5)*step/4;
+ ** but in shift step bits are dropped. The net result of this is
+ ** that even if you have fast mul/div hardware you cannot put it to
+ ** good use since the fixup would be too expensive.
+ */
+ delta = 0;
+ vpdiff = (step >> 3);
+
+ if ( diff >= step ) {
+ delta = 4;
+ diff -= step;
+ vpdiff += step;
+ }
+ step >>= 1;
+ if ( diff >= step ) {
+ delta |= 2;
+ diff -= step;
+ vpdiff += step;
+ }
+ step >>= 1;
+ if ( diff >= step ) {
+ delta |= 1;
+ vpdiff += step;
+ }
+
+ /* Step 3 - Update previous value */
+ if ( sign )
+ valpred -= vpdiff;
+ else
+ valpred += vpdiff;
+
+ /* Step 4 - Clamp previous value to 16 bits */
+ if ( valpred > 32767 )
+ valpred = 32767;
+ else if ( valpred < -32768 )
+ valpred = -32768;
+
+ /* Step 5 - Assemble value, update index and step values */
+ delta |= sign;
+
+ index += indexTable[delta];
+ if ( index < 0 ) index = 0;
+ if ( index > 88 ) index = 88;
+ step = stepsizeTable[index];
+
+ /* Step 6 - Output value */
+ if ( bufferstep ) {
+ outputbuffer = (delta << 4) & 0xf0;
+ } else {
+ *outp++ = (delta & 0x0f) | outputbuffer;
+ }
+ bufferstep = !bufferstep;
+ }
+
+ /* Output last step, if needed */
+ if ( !bufferstep )
+ *outp++ = outputbuffer;
+
+ state->sample = valpred;
+ state->index = index;
+}
+
+
+/* static */ void S_AdpcmDecode( const char indata[], short *outdata, int len, struct adpcm_state *state ) {
+ signed char *inp; /* Input buffer pointer */
+ int outp; /* output buffer pointer */
+ int sign; /* Current adpcm sign bit */
+ int delta; /* Current adpcm output value */
+ int step; /* Stepsize */
+ int valpred; /* Predicted value */
+ int vpdiff; /* Current change to valpred */
+ int index; /* Current step change index */
+ int inputbuffer; /* place to keep next 4-bit value */
+ int bufferstep; /* toggle between inputbuffer/input */
+
+ outp = 0;
+ inp = (signed char *)indata;
+
+ valpred = state->sample;
+ index = state->index;
+ step = stepsizeTable[index];
+
+ bufferstep = 0;
+ inputbuffer = 0; // quiet a compiler warning
+ for ( ; len > 0 ; len-- ) {
+
+ /* Step 1 - get the delta value */
+ if ( bufferstep ) {
+ delta = inputbuffer & 0xf;
+ } else {
+ inputbuffer = *inp++;
+ delta = (inputbuffer >> 4) & 0xf;
+ }
+ bufferstep = !bufferstep;
+
+ /* Step 2 - Find new index value (for later) */
+ index += indexTable[delta];
+ if ( index < 0 ) index = 0;
+ if ( index > 88 ) index = 88;
+
+ /* Step 3 - Separate sign and magnitude */
+ sign = delta & 8;
+ delta = delta & 7;
+
+ /* Step 4 - Compute difference and new predicted value */
+ /*
+ ** Computes 'vpdiff = (delta+0.5)*step/4', but see comment
+ ** in adpcm_coder.
+ */
+ vpdiff = step >> 3;
+ if ( delta & 4 ) vpdiff += step;
+ if ( delta & 2 ) vpdiff += step>>1;
+ if ( delta & 1 ) vpdiff += step>>2;
+
+ if ( sign )
+ valpred -= vpdiff;
+ else
+ valpred += vpdiff;
+
+ /* Step 5 - clamp output value */
+ if ( valpred > 32767 )
+ valpred = 32767;
+ else if ( valpred < -32768 )
+ valpred = -32768;
+
+ /* Step 6 - Update step value */
+ step = stepsizeTable[index];
+
+ /* Step 7 - Output value */
+ outdata[outp] = valpred;
+ outp++;
+ }
+
+ state->sample = valpred;
+ state->index = index;
+}
+
+
+/*
+====================
+S_AdpcmMemoryNeeded
+
+Returns the amount of memory (in bytes) needed to store the samples in out internal adpcm format
+====================
+*/
+int S_AdpcmMemoryNeeded( const wavinfo_t *info ) {
+ float scale;
+ int scaledSampleCount;
+ int sampleMemory;
+ int blockCount;
+ int headerMemory;
+
+ // determine scale to convert from input sampling rate to desired sampling rate
+ scale = (float)info->rate / dma.speed;
+
+ // calc number of samples at playback sampling rate
+ scaledSampleCount = info->samples / scale;
+
+ // calc memory need to store those samples using ADPCM at 4 bits per sample
+ sampleMemory = scaledSampleCount / 2;
+
+ // calc number of sample blocks needed of PAINTBUFFER_SIZE
+ blockCount = scaledSampleCount / PAINTBUFFER_SIZE;
+ if( scaledSampleCount % PAINTBUFFER_SIZE ) {
+ blockCount++;
+ }
+
+ // calc memory needed to store the block headers
+ headerMemory = blockCount * sizeof(adpcm_state_t);
+
+ return sampleMemory + headerMemory;
+}
+
+
+/*
+====================
+S_AdpcmGetSamples
+====================
+*/
+void S_AdpcmGetSamples(sndBuffer *chunk, short *to) {
+ adpcm_state_t state;
+ byte *out;
+
+ // get the starting state from the block header
+ state.index = chunk->adpcm.index;
+ state.sample = chunk->adpcm.sample;
+
+ out = (byte *)chunk->sndChunk;
+ // get samples
+ S_AdpcmDecode((char *) out, to, SND_CHUNK_SIZE_BYTE*2, &state );
+}
+
+
+/*
+====================
+S_AdpcmEncodeSound
+====================
+*/
+void S_AdpcmEncodeSound( sfx_t *sfx, short *samples ) {
+ adpcm_state_t state;
+ int inOffset;
+ int count;
+ int n;
+ sndBuffer *newchunk, *chunk;
+ byte *out;
+
+ inOffset = 0;
+ count = sfx->soundLength;
+ state.index = 0;
+ state.sample = samples[0];
+
+ chunk = NULL;
+ while( count ) {
+ n = count;
+ if( n > SND_CHUNK_SIZE_BYTE*2 ) {
+ n = SND_CHUNK_SIZE_BYTE*2;
+ }
+
+ newchunk = SND_malloc();
+ if (sfx->soundData == NULL) {
+ sfx->soundData = newchunk;
+ } else {
+ chunk->next = newchunk;
+ }
+ chunk = newchunk;
+
+ // output the header
+ chunk->adpcm.index = state.index;
+ chunk->adpcm.sample = state.sample;
+
+ out = (byte *)chunk->sndChunk;
+
+ // encode the samples
+ S_AdpcmEncode( samples + inOffset, (char *) out, n, &state );
+
+ inOffset += n;
+ count -= n;
+ }
+}
generated by cgit (git 2.34.1) at 2024-11-14 22:52:44 +0000