+++ /dev/null
-/*
- * Assorted DPCM codecs
- * Copyright (c) 2003 The ffmpeg Project.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-/**
- * @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
- *
- * 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];
-} 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,
- 8, 9, 10, 11, 12, 13, 14, 15,
- 16, 17, 18, 19, 20, 21, 22, 23,
- 24, 25, 26, 27, 28, 29, 30, 31,
- 32, 33, 34, 35, 36, 37, 38, 39,
- 40, 41, 42, 43, 47, 51, 56, 61,
- 66, 72, 79, 86, 94, 102, 112, 122,
- 133, 145, 158, 173, 189, 206, 225, 245,
- 267, 292, 318, 348, 379, 414, 452, 493,
- 538, 587, 640, 699, 763, 832, 908, 991,
- 1081, 1180, 1288, 1405, 1534, 1673, 1826, 1993,
- 2175, 2373, 2590, 2826, 3084, 3365, 3672, 4008,
- 4373, 4772, 5208, 5683, 6202, 6767, 7385, 8059,
- 8794, 9597, 10472, 11428, 12471, 13609, 14851, 16206,
- 17685, 19298, 21060, 22981, 25078, 27367, 29864, 32589,
- -29973, -26728, -23186, -19322, -15105, -10503, -5481, -1,
- 1, 1, 5481, 10503, 15105, 19322, 23186, 26728,
- 29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
- -17685, -16206, -14851, -13609, -12471, -11428, -10472, -9597,
- -8794, -8059, -7385, -6767, -6202, -5683, -5208, -4772,
- -4373, -4008, -3672, -3365, -3084, -2826, -2590, -2373,
- -2175, -1993, -1826, -1673, -1534, -1405, -1288, -1180,
- -1081, -991, -908, -832, -763, -699, -640, -587,
- -538, -493, -452, -414, -379, -348, -318, -292,
- -267, -245, -225, -206, -189, -173, -158, -145,
- -133, -122, -112, -102, -94, -86, -79, -72,
- -66, -61, -56, -51, -47, -43, -42, -41,
- -40, -39, -38, -37, -36, -35, -34, -33,
- -32, -31, -30, -29, -28, -27, -26, -25,
- -24, -23, -22, -21, -20, -19, -18, -17,
- -16, -15, -14, -13, -12, -11, -10, -9,
- -8, -7, -6, -5, -4, -3, -2, -1
-
-};
-
-static int dpcm_decode_init(AVCodecContext *avctx)
-{
- DPCMContext *s = avctx->priv_data;
- int i;
- short square;
-
- s->channels = avctx->channels;
-
- switch(avctx->codec->id) {
-
- case CODEC_ID_ROQ_DPCM:
- /* initialize square table */
- for (i = 0; i < 128; i++) {
- square = i * i;
- s->roq_square_array[i] = square;
- s->roq_square_array[i + 128] = -square;
- }
- break;
-
- default:
- break;
- }
-
- return 0;
-}
-
-static int dpcm_decode_frame(AVCodecContext *avctx,
- void *data, int *data_size,
- uint8_t *buf, int buf_size)
-{
- DPCMContext *s = avctx->priv_data;
- int in, out = 0;
- int predictor[2];
- int channel_number = 0;
- short *output_samples = data;
- int shift[2];
- unsigned char byte;
- short diff;
-
- switch(avctx->codec->id) {
-
- case CODEC_ID_ROQ_DPCM:
- if (s->channels == 1)
- predictor[0] = LE_16(&buf[6]);
- else {
- predictor[0] = buf[7] << 8;
- predictor[1] = buf[6] << 8;
- }
- SE_16BIT(predictor[0]);
- SE_16BIT(predictor[1]);
-
- /* decode the samples */
- for (in = 8, out = 0; in < buf_size; in++, out++) {
- predictor[channel_number] += s->roq_square_array[buf[in]];
- SATURATE_S16(predictor[channel_number]);
- output_samples[out] = predictor[channel_number];
-
- /* toggle channel */
- channel_number ^= s->channels - 1;
- }
- break;
-
- case CODEC_ID_INTERPLAY_DPCM:
- 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[1])
- output_samples[out++] = predictor[1];
- }
-
- while (in < buf_size) {
- predictor[channel_number] += interplay_delta_table[buf[in++]];
- SATURATE_S16(predictor[channel_number]);
- output_samples[out++] = predictor[channel_number];
-
- /* toggle channel */
- channel_number ^= s->channels - 1;
- }
-
- 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;
- }
-
- *data_size = out * sizeof(short);
- return buf_size;
-}
-
-AVCodec roq_dpcm_decoder = {
- "roq_dpcm",
- CODEC_TYPE_AUDIO,
- CODEC_ID_ROQ_DPCM,
- sizeof(DPCMContext),
- dpcm_decode_init,
- NULL,
- NULL,
- dpcm_decode_frame,
-};
-
-AVCodec interplay_dpcm_decoder = {
- "interplay_dpcm",
- CODEC_TYPE_AUDIO,
- CODEC_ID_INTERPLAY_DPCM,
- sizeof(DPCMContext),
- dpcm_decode_init,
- NULL,
- 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,
-};
projects / synfig.git / blobdiff