#include <stdint.h>
#include <stdio.h>
#include <string.h>
/* Note: This struct assumes a member alignment of 4 bytes.
** This matters when pitch_lag > 216 on the first subframe of any given frame.
*/
typedef struct UTKContext {
FILE *fp;
const uint8_t *ptr, *end;
int parsed_header;
unsigned int bits_value;
int bits_count;
int reduced_bw;
int multipulse_thresh;
float fixed_gains[64];
float rc[12];
float synth_history[12];
float adapt_cb[324];
float decompressed_frame[432];
} UTKContext;
enum { MDL_NORMAL = 0, MDL_LARGEPULSE = 1 };
static const float utk_rc_table[64] = {+0.0f,
-.99677598476409912109375f,
-.99032700061798095703125f,
-.983879029750823974609375f,
-.977430999279022216796875f,
-.970982015132904052734375f,
-.964533984661102294921875f,
-.958085000514984130859375f,
-.9516370296478271484375f,
-.930754005908966064453125f,
-.904959976673126220703125f,
-.879167020320892333984375f,
-.853372991085052490234375f,
-.827579021453857421875f,
-.801786005496978759765625f,
-.775991976261138916015625f,
-.75019800662994384765625f,
-.724404990673065185546875f,
-.6986110210418701171875f,
-.6706349849700927734375f,
-.61904799938201904296875f,
-.567460000514984130859375f,
-.515873014926910400390625f,
-.4642859995365142822265625f,
-.4126980006694793701171875f,
-.361110985279083251953125f,
-.309523999691009521484375f,
-.257937014102935791015625f,
-.20634900033473968505859375f,
-.1547619998455047607421875f,
-.10317499935626983642578125f,
-.05158700048923492431640625f,
+0.0f,
+.05158700048923492431640625f,
+.10317499935626983642578125f,
+.1547619998455047607421875f,
+.20634900033473968505859375f,
+.257937014102935791015625f,
+.309523999691009521484375f,
+.361110985279083251953125f,
+.4126980006694793701171875f,
+.4642859995365142822265625f,
+.515873014926910400390625f,
+.567460000514984130859375f,
+.61904799938201904296875f,
+.6706349849700927734375f,
+.6986110210418701171875f,
+.724404990673065185546875f,
+.75019800662994384765625f,
+.775991976261138916015625f,
+.801786005496978759765625f,
+.827579021453857421875f,
+.853372991085052490234375f,
+.879167020320892333984375f,
+.904959976673126220703125f,
+.930754005908966064453125f,
+.9516370296478271484375f,
+.958085000514984130859375f,
+.964533984661102294921875f,
+.970982015132904052734375f,
+.977430999279022216796875f,
+.983879029750823974609375f,
+.99032700061798095703125f,
+.99677598476409912109375f};
static const uint8_t utk_codebooks[2][256] = {
{/* normal model */
4, 6, 5, 9, 4, 6, 5, 13, 4, 6, 5, 10, 4, 6, 5, 17, 4, 6, 5, 9,
4, 6, 5, 14, 4, 6, 5, 10, 4, 6, 5, 21, 4, 6, 5, 9, 4, 6, 5, 13,
4, 6, 5, 10, 4, 6, 5, 18, 4, 6, 5, 9, 4, 6, 5, 14, 4, 6, 5, 10,
4, 6, 5, 25, 4, 6, 5, 9, 4, 6, 5, 13, 4, 6, 5, 10, 4, 6, 5, 17,
4, 6, 5, 9, 4, 6, 5, 14, 4, 6, 5, 10, 4, 6, 5, 22, 4, 6, 5, 9,
4, 6, 5, 13, 4, 6, 5, 10, 4, 6, 5, 18, 4, 6, 5, 9, 4, 6, 5, 14,
4, 6, 5, 10, 4, 6, 5, 0, 4, 6, 5, 9, 4, 6, 5, 13, 4, 6, 5, 10,
4, 6, 5, 17, 4, 6, 5, 9, 4, 6, 5, 14, 4, 6, 5, 10, 4, 6, 5, 21,
4, 6, 5, 9, 4, 6, 5, 13, 4, 6, 5, 10, 4, 6, 5, 18, 4, 6, 5, 9,
4, 6, 5, 14, 4, 6, 5, 10, 4, 6, 5, 26, 4, 6, 5, 9, 4, 6, 5, 13,
4, 6, 5, 10, 4, 6, 5, 17, 4, 6, 5, 9, 4, 6, 5, 14, 4, 6, 5, 10,
4, 6, 5, 22, 4, 6, 5, 9, 4, 6, 5, 13, 4, 6, 5, 10, 4, 6, 5, 18,
4, 6, 5, 9, 4, 6, 5, 14, 4, 6, 5, 10, 4, 6, 5, 2},
{/* large-pulse model */
4, 11, 7, 15, 4, 12, 8, 19, 4, 11, 7, 16, 4, 12, 8, 23, 4, 11, 7, 15,
4, 12, 8, 20, 4, 11, 7, 16, 4, 12, 8, 27, 4, 11, 7, 15, 4, 12, 8, 19,
4, 11, 7, 16, 4, 12, 8, 24, 4, 11, 7, 15, 4, 12, 8, 20, 4, 11, 7, 16,
4, 12, 8, 1, 4, 11, 7, 15, 4, 12, 8, 19, 4, 11, 7, 16, 4, 12, 8, 23,
4, 11, 7, 15, 4, 12, 8, 20, 4, 11, 7, 16, 4, 12, 8, 28, 4, 11, 7, 15,
4, 12, 8, 19, 4, 11, 7, 16, 4, 12, 8, 24, 4, 11, 7, 15, 4, 12, 8, 20,
4, 11, 7, 16, 4, 12, 8, 3, 4, 11, 7, 15, 4, 12, 8, 19, 4, 11, 7, 16,
4, 12, 8, 23, 4, 11, 7, 15, 4, 12, 8, 20, 4, 11, 7, 16, 4, 12, 8, 27,
4, 11, 7, 15, 4, 12, 8, 19, 4, 11, 7, 16, 4, 12, 8, 24, 4, 11, 7, 15,
4, 12, 8, 20, 4, 11, 7, 16, 4, 12, 8, 1, 4, 11, 7, 15, 4, 12, 8, 19,
4, 11, 7, 16, 4, 12, 8, 23, 4, 11, 7, 15, 4, 12, 8, 20, 4, 11, 7, 16,
4, 12, 8, 28, 4, 11, 7, 15, 4, 12, 8, 19, 4, 11, 7, 16, 4, 12, 8, 24,
4, 11, 7, 15, 4, 12, 8, 20, 4, 11, 7, 16, 4, 12, 8, 3}};
static const struct {
int next_model;
int code_size;
float pulse_value;
} utk_commands[29] = {{MDL_LARGEPULSE, 8, 0.0f}, {MDL_LARGEPULSE, 7, 0.0f},
{MDL_NORMAL, 8, 0.0f}, {MDL_NORMAL, 7, 0.0f},
{MDL_NORMAL, 2, 0.0f}, {MDL_NORMAL, 2, -1.0f},
{MDL_NORMAL, 2, +1.0f}, {MDL_NORMAL, 3, -1.0f},
{MDL_NORMAL, 3, +1.0f}, {MDL_LARGEPULSE, 4, -2.0f},
{MDL_LARGEPULSE, 4, +2.0f}, {MDL_LARGEPULSE, 3, -2.0f},
{MDL_LARGEPULSE, 3, +2.0f}, {MDL_LARGEPULSE, 5, -3.0f},
{MDL_LARGEPULSE, 5, +3.0f}, {MDL_LARGEPULSE, 4, -3.0f},
{MDL_LARGEPULSE, 4, +3.0f}, {MDL_LARGEPULSE, 6, -4.0f},
{MDL_LARGEPULSE, 6, +4.0f}, {MDL_LARGEPULSE, 5, -4.0f},
{MDL_LARGEPULSE, 5, +4.0f}, {MDL_LARGEPULSE, 7, -5.0f},
{MDL_LARGEPULSE, 7, +5.0f}, {MDL_LARGEPULSE, 6, -5.0f},
{MDL_LARGEPULSE, 6, +5.0f}, {MDL_LARGEPULSE, 8, -6.0f},
{MDL_LARGEPULSE, 8, +6.0f}, {MDL_LARGEPULSE, 7, -6.0f},
{MDL_LARGEPULSE, 7, +6.0f}};
static int utk_read_byte(UTKContext *ctx) {
if (ctx->ptr < ctx->end)
return *ctx->ptr++;
if (ctx->fp) {
static uint8_t buffer[4096];
size_t bytes_copied = fread(buffer, 1, sizeof(buffer), ctx->fp);
if (bytes_copied > 0 && bytes_copied <= sizeof(buffer)) {
ctx->ptr = buffer;
ctx->end = buffer + bytes_copied;
return *ctx->ptr++;
}
}
return 0;
}
static int16_t utk_read_i16(UTKContext *ctx) {
int x = utk_read_byte(ctx);
x = (x << 8) | utk_read_byte(ctx);
return x;
}
static int utk_read_bits(UTKContext *ctx, int count) {
int ret = ctx->bits_value & ((1 << count) - 1);
ctx->bits_value >>= count;
ctx->bits_count -= count;
if (ctx->bits_count < 8) {
/* read another byte */
ctx->bits_value |= utk_read_byte(ctx) << ctx->bits_count;
ctx->bits_count += 8;
}
return ret;
}
static void utk_parse_header(UTKContext *ctx) {
int i;
float multiplier;
ctx->reduced_bw = utk_read_bits(ctx, 1);
ctx->multipulse_thresh = 32 - utk_read_bits(ctx, 4);
ctx->fixed_gains[0] = 8.0f * (1 + utk_read_bits(ctx, 4));
multiplier = 1.04f + utk_read_bits(ctx, 6) * 0.001f;
for (i = 1; i < 64; i++)
ctx->fixed_gains[i] = ctx->fixed_gains[i - 1] * multiplier;
}
static void utk_decode_excitation(UTKContext *ctx, int use_multipulse,
float *out, int stride) {
int i;
if (use_multipulse) {
/* multi-pulse model: n pulses are coded explicitly; the rest are zero */
int model, cmd;
model = 0;
i = 0;
while (i < 108) {
cmd = utk_codebooks[model][ctx->bits_value & 0xff];
model = utk_commands[cmd].next_model;
utk_read_bits(ctx, utk_commands[cmd].code_size);
if (cmd > 3) {
/* insert a pulse with magnitude <= 6.0f */
out[i] = utk_commands[cmd].pulse_value;
i += stride;
} else if (cmd > 1) {
/* insert between 7 and 70 zeros */
int count = 7 + utk_read_bits(ctx, 6);
if (i + count * stride > 108)
count = (108 - i) / stride;
while (count > 0) {
out[i] = 0.0f;
i += stride;
count--;
}
} else {
/* insert a pulse with magnitude >= 7.0f */
int x = 7;
while (utk_read_bits(ctx, 1))
x++;
if (!utk_read_bits(ctx, 1))
x *= -1;
out[i] = (float)x;
i += stride;
}
}
} else {
/* RELP model: entire residual (excitation) signal is coded explicitly */
i = 0;
while (i < 108) {
if (!utk_read_bits(ctx, 1))
out[i] = 0.0f;
else if (!utk_read_bits(ctx, 1))
out[i] = -2.0f;
else
out[i] = 2.0f;
i += stride;
}
}
}
static void rc_to_lpc(const float *rc, float *lpc) {
int i, j;
float tmp1[12];
float tmp2[12];
for (i = 10; i >= 0; i--)
tmp2[1 + i] = rc[i];
tmp2[0] = 1.0f;
for (i = 0; i < 12; i++) {
float x = -tmp2[11] * rc[11];
for (j = 10; j >= 0; j--) {
x -= tmp2[j] * rc[j];
tmp2[j + 1] = x * rc[j] + tmp2[j];
}
tmp1[i] = tmp2[0] = x;
for (j = 0; j < i; j++)
x -= tmp1[i - 1 - j] * lpc[j];
lpc[i] = x;
}
}
static void utk_lp_synthesis_filter(UTKContext *ctx, int offset,
int num_blocks) {
int i, j, k;
float lpc[12];
float *ptr = &ctx->decompressed_frame[offset];
rc_to_lpc(ctx->rc, lpc);
for (i = 0; i < num_blocks; i++) {
for (j = 0; j < 12; j++) {
float x = *ptr;
for (k = 0; k < j; k++)
x += lpc[k] * ctx->synth_history[k - j + 12];
for (; k < 12; k++)
x += lpc[k] * ctx->synth_history[k - j];
ctx->synth_history[11 - j] = x;
*ptr++ = x;
}
}
}
/*
** Public functions.
*/
static void utk_decode_frame(UTKContext *ctx) {
int i, j;
int use_multipulse = 0;
float excitation[5 + 108 + 5];
float rc_delta[12];
if (!ctx->bits_count) {
ctx->bits_value = utk_read_byte(ctx);
ctx->bits_count = 8;
}
if (!ctx->parsed_header) {
utk_parse_header(ctx);
ctx->parsed_header = 1;
}
memset(&excitation[0], 0, 5 * sizeof(float));
memset(&excitation[5 + 108], 0, 5 * sizeof(float));
/* read the reflection coefficients */
for (i = 0; i < 12; i++) {
int idx;
if (i == 0) {
idx = utk_read_bits(ctx, 6);
if (idx < ctx->multipulse_thresh)
use_multipulse = 1;
} else if (i < 4) {
idx = utk_read_bits(ctx, 6);
} else {
idx = 16 + utk_read_bits(ctx, 5);
}
rc_delta[i] = (utk_rc_table[idx] - ctx->rc[i]) * 0.25f;
}
/* decode four subframes */
for (i = 0; i < 4; i++) {
int pitch_lag = utk_read_bits(ctx, 8);
float pitch_gain = (float)utk_read_bits(ctx, 4) / 15.0f;
float fixed_gain = ctx->fixed_gains[utk_read_bits(ctx, 6)];
if (!ctx->reduced_bw) {
utk_decode_excitation(ctx, use_multipulse, &excitation[5], 1);
} else {
/* residual (excitation) signal is encoded at reduced bandwidth */
int align = utk_read_bits(ctx, 1);
int zero = utk_read_bits(ctx, 1);
utk_decode_excitation(ctx, use_multipulse, &excitation[5 + align], 2);
if (zero) {
/* fill the remaining samples with zero
** (spectrum is duplicated into high frequencies) */
for (j = 0; j < 54; j++)
excitation[5 + (1 - align) + 2 * j] = 0.0f;
} else {
/* interpolate the remaining samples
** (spectrum is low-pass filtered) */
float *ptr = &excitation[5 + (1 - align)];
for (j = 0; j < 108; j += 2)
ptr[j] = ptr[j - 5] * 0.01803267933428287506103515625f -
ptr[j - 3] * 0.114591561257839202880859375f +
ptr[j - 1] * 0.597385942935943603515625f +
ptr[j + 1] * 0.597385942935943603515625f -
ptr[j + 3] * 0.114591561257839202880859375f +
ptr[j + 5] * 0.01803267933428287506103515625f;
/* scale by 0.5f to give the sinc impulse response unit energy */
fixed_gain *= 0.5f;
}
}
for (j = 0; j < 108; j++)
ctx->decompressed_frame[108 * i + j] =
fixed_gain * excitation[5 + j] +
pitch_gain * ctx->adapt_cb[108 * i + 216 - pitch_lag + j];
}
for (i = 0; i < 324; i++)
ctx->adapt_cb[i] = ctx->decompressed_frame[108 + i];
for (i = 0; i < 4; i++) {
for (j = 0; j < 12; j++)
ctx->rc[j] += rc_delta[j];
utk_lp_synthesis_filter(ctx, 12 * i, i < 3 ? 1 : 33);
}
}
static void utk_init(UTKContext *ctx) { memset(ctx, 0, sizeof(*ctx)); }
static void utk_set_fp(UTKContext *ctx, FILE *fp) {
ctx->fp = fp;
/* reset the bit reader */
ctx->bits_count = 0;
}
static void utk_set_ptr(UTKContext *ctx, const uint8_t *ptr,
const uint8_t *end) {
ctx->ptr = ptr;
ctx->end = end;
/* reset the bit reader */
ctx->bits_count = 0;
}
/*
** MicroTalk Revision 3 decoding function.
*/
static void utk_rev3_decode_frame(UTKContext *ctx) {
int pcm_data_present = (utk_read_byte(ctx) == 0xee);
int i;
utk_decode_frame(ctx);
/* unread the last 8 bits and reset the bit reader */
ctx->ptr--;
ctx->bits_count = 0;
if (pcm_data_present) {
/* Overwrite n samples at a given offset in the decoded frame with
** raw PCM data. */
int offset = utk_read_i16(ctx);
int count = utk_read_i16(ctx);
/* sx.exe does not do any bounds checking or clamping of these two
** fields (see 004274D1 in sx.exe v3.01.01), which means a specially
** crafted MT5:1 file can crash sx.exe.
** We will throw an error instead. */
if (offset < 0 || offset > 432) {
fprintf(stderr, "error: invalid PCM offset %d\n", offset);
exit(EXIT_FAILURE);
}
if (count < 0 || count > 432 - offset) {
fprintf(stderr, "error: invalid PCM count %d\n", count);
exit(EXIT_FAILURE);
}
for (i = 0; i < count; i++)
ctx->decompressed_frame[offset + i] = (float)utk_read_i16(ctx);
}
}