* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "avcodec.h"
+#include "bitstream.h"
/**
* @file adpcm.c
0x0133, 0x0199, 0x0200, 0x0266
};
+// padded to zero where table size is less then 16
+static int swf_index_tables[4][16] = {
+ /*2*/ { -1, 2 },
+ /*3*/ { -1, -1, 2, 4 },
+ /*4*/ { -1, -1, -1, -1, 2, 4, 6, 8 },
+ /*5*/ { -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 4, 6, 8, 10, 13, 16 }
+};
+
/* end of tables */
typedef struct ADPCMChannelStatus {
int channel; /* for stereo MOVs, decode left, then decode right, then tell it's decoded */
ADPCMChannelStatus status[2];
short sample_buffer[32]; /* hold left samples while waiting for right samples */
+
+ /* SWF only */
+ int nb_bits;
+ int nb_samples;
} ADPCMContext;
/* XXX: implement encoding */
src++;
}
break;
+ case CODEC_ID_ADPCM_SWF:
+ {
+ GetBitContext gb;
+ int *table;
+ int k0, signmask;
+ int size = buf_size*8;
+
+ init_get_bits(&gb, buf, size);
+
+ // first frame, read bits & inital values
+ if (!c->nb_bits)
+ {
+ c->nb_bits = get_bits(&gb, 2)+2;
+// av_log(NULL,AV_LOG_INFO,"nb_bits: %d\n", c->nb_bits);
+ }
+
+ table = swf_index_tables[c->nb_bits-2];
+ k0 = 1 << (c->nb_bits-2);
+ signmask = 1 << (c->nb_bits-1);
+
+ while (get_bits_count(&gb) <= size)
+ {
+ int i;
+
+ c->nb_samples++;
+ // wrap around at every 4096 samples...
+ if ((c->nb_samples & 0xfff) == 1)
+ {
+ for (i = 0; i <= st; i++)
+ {
+ *samples++ = c->status[i].predictor = get_sbits(&gb, 16);
+ c->status[i].step_index = get_bits(&gb, 6);
+ }
+ }
+
+ // similar to IMA adpcm
+ for (i = 0; i <= st; i++)
+ {
+ int delta = get_bits(&gb, c->nb_bits);
+ int step = step_table[c->status[i].step_index];
+ long vpdiff = 0; // vpdiff = (delta+0.5)*step/4
+ int k = k0;
+
+ do {
+ if (delta & k)
+ vpdiff += step;
+ step >>= 1;
+ k >>= 1;
+ } while(k);
+ vpdiff += step;
+
+ if (delta & signmask)
+ c->status[i].predictor -= vpdiff;
+ else
+ c->status[i].predictor += vpdiff;
+
+ c->status[i].step_index += table[delta & (~signmask)];
+
+ c->status[i].step_index = clip(c->status[i].step_index, 0, 88);
+ c->status[i].predictor = clip(c->status[i].predictor, -32768, 32767);
+
+ *samples++ = c->status[i].predictor;
+ }
+ }
+
+// src += get_bits_count(&gb)*8;
+ src += size;
+
+ break;
+ }
default:
return -1;
}
ADPCM_CODEC(CODEC_ID_ADPCM_ADX, adpcm_adx);
ADPCM_CODEC(CODEC_ID_ADPCM_EA, adpcm_ea);
ADPCM_CODEC(CODEC_ID_ADPCM_CT, adpcm_ct);
+ADPCM_CODEC(CODEC_ID_ADPCM_SWF, adpcm_swf);
#undef ADPCM_CODEC