* @file: dpcm.c
* Assorted DPCM (differential pulse code modulation) audio codecs
* by Mike Melanson (melanson@pcisys.net)
+ * Xan DPCM decoder by Mario Brito (mbrito@student.dei.uc.pt)
* for more information on the specific data formats, visit:
* http://www.pcisys.net/~melanson/codecs/simpleaudio.html
+ * SOL DPCMs implemented by Konstantin Shishkov
+ *
+ * Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files
+ * found in the Wing Commander IV computer game. These AVI files contain
+ * WAVEFORMAT headers which report the audio format as 0x01: raw PCM.
+ * Clearly incorrect. To detect Xan DPCM, you will probably have to
+ * special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan'
+ * (Xan video) for its video codec. Alternately, such AVI files also contain
+ * the fourcc 'Axan' in the 'auds' chunk of the AVI header.
*/
#include "avcodec.h"
typedef struct DPCMContext {
int channels;
short roq_square_array[256];
- int last_delta[2];
+ long sample[2];//for SOL_DPCM
+ int *sol_table;//for SOL_DPCM
} DPCMContext;
#define SATURATE_S16(x) if (x < -32768) x = -32768; \
else if (x > 32767) x = 32767;
#define SE_16BIT(x) if (x & 0x8000) x -= 0x10000;
-#define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
-#define LE_32(x) ((((uint8_t*)(x))[3] << 24) | \
- (((uint8_t*)(x))[2] << 16) | \
- (((uint8_t*)(x))[1] << 8) | \
- ((uint8_t*)(x))[0])
static int interplay_delta_table[] = {
0, 1, 2, 3, 4, 5, 6, 7,
};
+static int sol_table_old[16] =
+ { 0x0, 0x1, 0x2 , 0x3, 0x6, 0xA, 0xF, 0x15,
+ -0x15, -0xF, -0xA, -0x6, -0x3, -0x2, -0x1, 0x0};
+
+static int sol_table_new[16] =
+ { 0x0, 0x1, 0x2, 0x3, 0x6, 0xA, 0xF, 0x15,
+ 0x0, -0x1, -0x2, -0x3, -0x6, -0xA, -0xF, -0x15};
+
+static int sol_table_16[128] = {
+ 0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
+ 0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
+ 0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
+ 0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
+ 0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
+ 0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
+ 0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
+ 0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
+ 0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
+ 0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
+ 0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
+ 0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
+ 0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
+};
+
+
+
static int dpcm_decode_init(AVCodecContext *avctx)
{
DPCMContext *s = avctx->priv_data;
short square;
s->channels = avctx->channels;
+ s->sample[0] = s->sample[1] = 0;
switch(avctx->codec->id) {
}
break;
+
+ case CODEC_ID_SOL_DPCM:
+ switch(avctx->codec_tag){
+ case 1:
+ s->sol_table=sol_table_old;
+ s->sample[0] = s->sample[1] = 0x80;
+ break;
+ case 2:
+ s->sol_table=sol_table_new;
+ s->sample[0] = s->sample[1] = 0x80;
+ break;
+ case 3:
+ s->sol_table=sol_table_16;
+ break;
+ default:
+ av_log(avctx, AV_LOG_ERROR, "Unknown SOL subcodec\n");
+ return -1;
+ }
+ break;
+
default:
break;
}
{
DPCMContext *s = avctx->priv_data;
int in, out = 0;
- int i;
int predictor[2];
int channel_number = 0;
short *output_samples = data;
- int sequence_number;
+ int shift[2];
+ unsigned char byte;
+ short diff;
+
+ if (!buf_size)
+ return 0;
switch(avctx->codec->id) {
break;
case CODEC_ID_INTERPLAY_DPCM:
- in = 0;
- sequence_number = LE_16(&buf[in]);
- in += 6; /* skip over the stream mask and stream length */
- if (sequence_number == 1) {
- predictor[0] = LE_16(&buf[in]);
+ in = 6; /* skip over the stream mask and stream length */
+ predictor[0] = LE_16(&buf[in]);
+ in += 2;
+ SE_16BIT(predictor[0])
+ output_samples[out++] = predictor[0];
+ if (s->channels == 2) {
+ predictor[1] = LE_16(&buf[in]);
in += 2;
- SE_16BIT(predictor[0])
- if (s->channels == 2) {
- predictor[1] = LE_16(&buf[in]);
- SE_16BIT(predictor[1])
- in += 2;
- }
- } else {
- for (i = 0; i < s->channels; i++)
- predictor[i] = s->last_delta[i];
+ SE_16BIT(predictor[1])
+ output_samples[out++] = predictor[1];
}
while (in < buf_size) {
channel_number ^= s->channels - 1;
}
- /* save predictors for next round */
- for (i = 0; i < s->channels; i++)
- s->last_delta[i] = predictor[i];
+ break;
+
+ case CODEC_ID_XAN_DPCM:
+ in = 0;
+ shift[0] = shift[1] = 4;
+ predictor[0] = LE_16(&buf[in]);
+ in += 2;
+ SE_16BIT(predictor[0]);
+ if (s->channels == 2) {
+ predictor[1] = LE_16(&buf[in]);
+ in += 2;
+ SE_16BIT(predictor[1]);
+ }
+
+ while (in < buf_size) {
+ byte = buf[in++];
+ diff = (byte & 0xFC) << 8;
+ if ((byte & 0x03) == 3)
+ shift[channel_number]++;
+ else
+ shift[channel_number] -= (2 * (byte & 3));
+ /* saturate the shifter to a lower limit of 0 */
+ if (shift[channel_number] < 0)
+ shift[channel_number] = 0;
+
+ diff >>= shift[channel_number];
+ predictor[channel_number] += diff;
+
+ SATURATE_S16(predictor[channel_number]);
+ output_samples[out++] = predictor[channel_number];
+ /* toggle channel */
+ channel_number ^= s->channels - 1;
+ }
+ break;
+ case CODEC_ID_SOL_DPCM:
+ in = 0;
+ if (avctx->codec_tag != 3) {
+ while (in < buf_size) {
+ int n1, n2;
+ n1 = (buf[in] >> 4) & 0xF;
+ n2 = buf[in++] & 0xF;
+ s->sample[0] += s->sol_table[n1];
+ if (s->sample[0] < 0) s->sample[0] = 0;
+ if (s->sample[0] > 255) s->sample[0] = 255;
+ output_samples[out++] = (s->sample[0] - 128) << 8;
+ s->sample[s->channels - 1] += s->sol_table[n2];
+ if (s->sample[s->channels - 1] < 0) s->sample[s->channels - 1] = 0;
+ if (s->sample[s->channels - 1] > 255) s->sample[s->channels - 1] = 255;
+ output_samples[out++] = (s->sample[s->channels - 1] - 128) << 8;
+ }
+ } else {
+ while (in < buf_size) {
+ int n;
+ n = buf[in++];
+ if (n & 0x80) s->sample[channel_number] -= s->sol_table[n & 0x7F];
+ else s->sample[channel_number] += s->sol_table[n & 0x7F];
+ SATURATE_S16(s->sample[channel_number]);
+ output_samples[out++] = s->sample[channel_number];
+ /* toggle channel */
+ channel_number ^= s->channels - 1;
+ }
+ }
break;
}
NULL,
dpcm_decode_frame,
};
+
+AVCodec xan_dpcm_decoder = {
+ "xan_dpcm",
+ CODEC_TYPE_AUDIO,
+ CODEC_ID_XAN_DPCM,
+ sizeof(DPCMContext),
+ dpcm_decode_init,
+ NULL,
+ NULL,
+ dpcm_decode_frame,
+};
+
+AVCodec sol_dpcm_decoder = {
+ "sol_dpcm",
+ CODEC_TYPE_AUDIO,
+ CODEC_ID_SOL_DPCM,
+ sizeof(DPCMContext),
+ dpcm_decode_init,
+ NULL,
+ NULL,
+ dpcm_decode_frame,
+};
projects / ffmpeg / blobdiff