int qt_ima_adpcm_decode_block(unsigned short *output,
unsigned char *input, int channels)
{
int initial_predictor_l = 0;
int initial_predictor_r = 0;
int initial_index_l = 0;
int initial_index_r = 0;
int i;
initial_predictor_l = BE_16(&input[0]);
initial_index_l = initial_predictor_l;
// mask, sign-extend, and clamp the predictor portion
initial_predictor_l &= 0xFF80;
SE_16BIT(initial_predictor_l);
CLAMP_S16(initial_predictor_l);
// mask and clamp the index portion
initial_index_l &= 0x7F;
CLAMP_0_TO_88(initial_index_l);
// handle stereo
if (channels > 1)
{
initial_predictor_r = BE_16(&input[QT_IMA_ADPCM_BLOCK_SIZE]);
initial_index_r = initial_predictor_r;
// mask, sign-extend, and clamp the predictor portion
initial_predictor_r &= 0xFF80;
SE_16BIT(initial_predictor_r);
CLAMP_S16(initial_predictor_r);
// mask and clamp the index portion
initial_index_r &= 0x7F;
CLAMP_0_TO_88(initial_index_r);
}
// break apart all of the nibbles in the block
if (channels == 1)
for (i = 0; i < QT_IMA_ADPCM_SAMPLES_PER_BLOCK / 2; i++)
{
output[i * 2 + 0] = input[2 + i] & 0x0F;
output[i * 2 + 1] = input[2 + i] >> 4;
}
else
for (i = 0; i < QT_IMA_ADPCM_SAMPLES_PER_BLOCK / 2 * 2; i++)
static int ms_adpcm_decode_block(unsigned short *output, unsigned char *input,
int channels, int block_size)
{
int current_channel = 0;
int idelta[2];
int sample1[2];
int sample2[2];
int coeff1[2];
int coeff2[2];
int stream_ptr = 0;
int out_ptr = 0;
int upper_nibble = 1;
int nibble;
int snibble; // signed nibble
int predictor;
// fetch the header information, in stereo if both channels are present
if (input[stream_ptr] > 6)
mp_msg(MSGT_DECAUDIO, MSGL_WARN,
"MS ADPCM: coefficient (%d) out of range (should be [0..6])\n",
input[stream_ptr]);
coeff1[0] = ms_adapt_coeff1[input[stream_ptr]];
coeff2[0] = ms_adapt_coeff2[input[stream_ptr]];
stream_ptr++;
if (channels == 2)
{
if (input[stream_ptr] > 6)
mp_msg(MSGT_DECAUDIO, MSGL_WARN,
"MS ADPCM: coefficient (%d) out of range (should be [0..6])\n",
input[stream_ptr]);
coeff1[1] = ms_adapt_coeff1[input[stream_ptr]];
coeff2[1] = ms_adapt_coeff2[input[stream_ptr]];
stream_ptr++;
}
idelta[0] = LE_16(&input[stream_ptr]);
stream_ptr += 2;
SE_16BIT(idelta[0]);
if (channels == 2)
{
idelta[1] = LE_16(&input[stream_ptr]);
stream_ptr += 2;
SE_16BIT(idelta[1]);
}
sample1[0] = LE_16(&input[stream_ptr]);
stream_ptr += 2;
SE_16BIT(sample1[0]);
if (channels == 2)
{
sample1[1] = LE_16(&input[stream_ptr]);
stream_ptr += 2;
SE_16BIT(sample1[1]);
}
sample2[0] = LE_16(&input[stream_ptr]);
stream_ptr += 2;
SE_16BIT(sample2[0]);
if (channels == 2)
{
sample2[1] = LE_16(&input[stream_ptr]);
stream_ptr += 2;
SE_16BIT(sample2[1]);
}
if (channels == 1)
{
output[out_ptr++] = sample2[0];
output[out_ptr++] = sample1[0];
} else {
output[out_ptr++] = sample2[0];
output[out_ptr++] = sample2[1];
output[out_ptr++] = sample1[0];
output[out_ptr++] = sample1[1];
}
while (stream_ptr < block_size)
{
// get the next nibble
if (upper_nibble)
nibble = snibble = input[stream_ptr] >> 4;
else
nibble = snibble = input[stream_ptr++] & 0x0F;
upper_nibble ^= 1;
SE_4BIT(snibble);
predictor = (
((sample1[current_channel] * coeff1[current_channel]) +
(sample2[current_channel] * coeff2[current_channel])) / 256) +
(snibble * idelta[current_channel]);
CLAMP_S16(predictor);
sample2[current_channel] = sample1[current_channel];
sample1[current_channel] = predictor;
output[out_ptr++] = predictor;
// compute the next adaptive scale factor (a.k.a. the variable idelta)
idelta[current_channel] =
(ms_adapt_table[nibble] * idelta[current_channel]) / 256;
CLAMP_ABOVE_16(idelta[current_channel]);
// toggle the channel
current_channel ^= channels - 1;
}
// note: This decoder assumes the format 0x62 data always comes in
// stereo flavor
static int dk3_adpcm_decode_block(unsigned short *output, unsigned char *input,
int block_size)
{
int sum_pred;
int diff_pred;
int sum_index;
int diff_index;
int diff_channel;
int in_ptr = 0x10;
int out_ptr = 0;
unsigned char last_byte = 0;
unsigned char nibble;
int decode_top_nibble_next = 0;
// ADPCM work variables
int sign;
int delta;
int step;
int diff;
sum_pred = LE_16(&input[10]);
diff_pred = LE_16(&input[12]);
SE_16BIT(sum_pred);
SE_16BIT(diff_pred);
diff_channel = diff_pred;
sum_index = input[14];
diff_index = input[15];
while (in_ptr < block_size - !decode_top_nibble_next)
// while (in_ptr < 2048)
{
// process the first predictor of the sum channel
DK3_GET_NEXT_NIBBLE();
step = adpcm_step[sum_index];
sign = nibble & 8;
delta = nibble & 7;
diff = step >> 3;
if (delta & 4) diff += step;
if (delta & 2) diff += step >> 1;
if (delta & 1) diff += step >> 2;
if (sign)
sum_pred -= diff;
else
sum_pred += diff;
CLAMP_S16(sum_pred);
sum_index += adpcm_index[nibble];
CLAMP_0_TO_88(sum_index);
// process the diff channel predictor
DK3_GET_NEXT_NIBBLE();
step = adpcm_step[diff_index];
sign = nibble & 8;
delta = nibble & 7;
diff = step >> 3;
if (delta & 4) diff += step;
if (delta & 2) diff += step >> 1;
if (delta & 1) diff += step >> 2;
if (sign)
diff_pred -= diff;
else
diff_pred += diff;
CLAMP_S16(diff_pred);
diff_index += adpcm_index[nibble];
CLAMP_0_TO_88(diff_index);
// output the first pair of stereo PCM samples
diff_channel = (diff_channel + diff_pred) / 2;
output[out_ptr++] = sum_pred + diff_channel;
output[out_ptr++] = sum_pred - diff_channel;
// process the second predictor of the sum channel
DK3_GET_NEXT_NIBBLE();
step = adpcm_step[sum_index];
sign = nibble & 8;
delta = nibble & 7;
diff = step >> 3;
if (delta & 4) diff += step;
if (delta & 2) diff += step >> 1;
if (delta & 1) diff += step >> 2;
if (sign)
sum_pred -= diff;
else
sum_pred += diff;
CLAMP_S16(sum_pred);
sum_index += adpcm_index[nibble];
CLAMP_0_TO_88(sum_index);
// output the second pair of stereo PCM samples
output[out_ptr++] = sum_pred + diff_channel;
output[out_ptr++] = sum_pred - diff_channel;
}
return out_ptr;
}
