#include "mathops.h"
typedef struct DPCMContext {
- int16_t square_array[256];
+ int16_t array[256];
int sample[2]; ///< previous sample (for SOL_DPCM)
const int8_t *sol_table; ///< delta table for SOL_DPCM
} DPCMContext;
/* initialize square table */
for (i = 0; i < 128; i++) {
int16_t square = i * i;
- s->square_array[i ] = square;
- s->square_array[i + 128] = -square;
+ s->array[i ] = square;
+ s->array[i + 128] = -square;
}
break;
case AV_CODEC_ID_SDX2_DPCM:
for (i = -128; i < 128; i++) {
int16_t square = i * i * 2;
- s->square_array[i+128] = i < 0 ? -square: square;
+ s->array[i+128] = i < 0 ? -square: square;
+ }
+ break;
+
+ case AV_CODEC_ID_GREMLIN_DPCM: {
+ int delta = 0;
+ int code = 64;
+ int step = 45;
+
+ s->array[0] = 0;
+ for (i = 0; i < 127; i++) {
+ delta += (code >> 5);
+ code += step;
+ step += 2;
+
+ s->array[i*2 + 1] = delta;
+ s->array[i*2 + 2] = -delta;
+ }
+ s->array[255] = delta + (code >> 5);
}
break;
else
out = buf_size;
break;
+ case AV_CODEC_ID_GREMLIN_DPCM:
case AV_CODEC_ID_SDX2_DPCM:
out = buf_size;
break;
/* decode the samples */
while (output_samples < samples_end) {
- predictor[ch] += s->square_array[bytestream2_get_byteu(&gb)];
+ predictor[ch] += s->array[bytestream2_get_byteu(&gb)];
predictor[ch] = av_clip_int16(predictor[ch]);
*output_samples++ = predictor[ch];
if (!(n & 1))
s->sample[ch] = 0;
- s->sample[ch] += s->square_array[n + 128];
+ s->sample[ch] += s->array[n + 128];
s->sample[ch] = av_clip_int16(s->sample[ch]);
*output_samples++ = s->sample[ch];
ch ^= stereo;
}
break;
+
+ case AV_CODEC_ID_GREMLIN_DPCM: {
+ int idx = 0;
+
+ while (output_samples < samples_end) {
+ uint8_t n = bytestream2_get_byteu(&gb);
+
+ *output_samples++ = s->sample[idx] += s->array[n];
+ idx ^= 1;
+ }
+ }
+ break;
}
*got_frame_ptr = 1;
.capabilities = AV_CODEC_CAP_DR1, \
}
+DPCM_DECODER(AV_CODEC_ID_GREMLIN_DPCM, gremlin_dpcm, "DPCM Gremlin");
DPCM_DECODER(AV_CODEC_ID_INTERPLAY_DPCM, interplay_dpcm, "DPCM Interplay");
DPCM_DECODER(AV_CODEC_ID_ROQ_DPCM, roq_dpcm, "DPCM id RoQ");
DPCM_DECODER(AV_CODEC_ID_SDX2_DPCM, sdx2_dpcm, "DPCM Squareroot-Delta-Exact");