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248 lines
8.2 KiB
248 lines
8.2 KiB
/* |
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* Assorted DPCM codecs |
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* Copyright (c) 2003 The ffmpeg Project. |
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* |
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* This library is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2 of the License, or (at your option) any later version. |
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* |
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* This library is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with this library; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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/** |
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* @file: dpcm.c |
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* Assorted DPCM (differential pulse code modulation) audio codecs |
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* by Mike Melanson (melanson@pcisys.net) |
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* Xan DPCM decoder by Mario Brito (mbrito@student.dei.uc.pt) |
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* for more information on the specific data formats, visit: |
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* http://www.pcisys.net/~melanson/codecs/simpleaudio.html |
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* |
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* Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files |
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* found in the Wing Commander IV computer game. These AVI files contain |
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* WAVEFORMAT headers which report the audio format as 0x01: raw PCM. |
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* Clearly incorrect. To detect Xan DPCM, you will probably have to |
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* special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan' |
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* (Xan video) for its video codec. Alternately, such AVI files also contain |
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* the fourcc 'Axan' in the 'auds' chunk of the AVI header. |
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*/ |
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#include "avcodec.h" |
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typedef struct DPCMContext { |
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int channels; |
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short roq_square_array[256]; |
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} DPCMContext; |
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#define SATURATE_S16(x) if (x < -32768) x = -32768; \ |
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else if (x > 32767) x = 32767; |
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#define SE_16BIT(x) if (x & 0x8000) x -= 0x10000; |
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#define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0]) |
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#define LE_32(x) ((((uint8_t*)(x))[3] << 24) | \ |
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(((uint8_t*)(x))[2] << 16) | \ |
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(((uint8_t*)(x))[1] << 8) | \ |
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((uint8_t*)(x))[0]) |
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static int interplay_delta_table[] = { |
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0, 1, 2, 3, 4, 5, 6, 7, |
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8, 9, 10, 11, 12, 13, 14, 15, |
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16, 17, 18, 19, 20, 21, 22, 23, |
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24, 25, 26, 27, 28, 29, 30, 31, |
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32, 33, 34, 35, 36, 37, 38, 39, |
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40, 41, 42, 43, 47, 51, 56, 61, |
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66, 72, 79, 86, 94, 102, 112, 122, |
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133, 145, 158, 173, 189, 206, 225, 245, |
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267, 292, 318, 348, 379, 414, 452, 493, |
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538, 587, 640, 699, 763, 832, 908, 991, |
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1081, 1180, 1288, 1405, 1534, 1673, 1826, 1993, |
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2175, 2373, 2590, 2826, 3084, 3365, 3672, 4008, |
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4373, 4772, 5208, 5683, 6202, 6767, 7385, 8059, |
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8794, 9597, 10472, 11428, 12471, 13609, 14851, 16206, |
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17685, 19298, 21060, 22981, 25078, 27367, 29864, 32589, |
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-29973, -26728, -23186, -19322, -15105, -10503, -5481, -1, |
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1, 1, 5481, 10503, 15105, 19322, 23186, 26728, |
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29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298, |
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-17685, -16206, -14851, -13609, -12471, -11428, -10472, -9597, |
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-8794, -8059, -7385, -6767, -6202, -5683, -5208, -4772, |
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-4373, -4008, -3672, -3365, -3084, -2826, -2590, -2373, |
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-2175, -1993, -1826, -1673, -1534, -1405, -1288, -1180, |
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-1081, -991, -908, -832, -763, -699, -640, -587, |
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-538, -493, -452, -414, -379, -348, -318, -292, |
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-267, -245, -225, -206, -189, -173, -158, -145, |
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-133, -122, -112, -102, -94, -86, -79, -72, |
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-66, -61, -56, -51, -47, -43, -42, -41, |
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-40, -39, -38, -37, -36, -35, -34, -33, |
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-32, -31, -30, -29, -28, -27, -26, -25, |
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-24, -23, -22, -21, -20, -19, -18, -17, |
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-16, -15, -14, -13, -12, -11, -10, -9, |
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-8, -7, -6, -5, -4, -3, -2, -1 |
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}; |
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static int dpcm_decode_init(AVCodecContext *avctx) |
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{ |
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DPCMContext *s = avctx->priv_data; |
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int i; |
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short square; |
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s->channels = avctx->channels; |
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switch(avctx->codec->id) { |
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case CODEC_ID_ROQ_DPCM: |
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/* initialize square table */ |
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for (i = 0; i < 128; i++) { |
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square = i * i; |
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s->roq_square_array[i] = square; |
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s->roq_square_array[i + 128] = -square; |
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} |
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break; |
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default: |
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break; |
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} |
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return 0; |
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} |
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static int dpcm_decode_frame(AVCodecContext *avctx, |
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void *data, int *data_size, |
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uint8_t *buf, int buf_size) |
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{ |
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DPCMContext *s = avctx->priv_data; |
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int in, out = 0; |
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int predictor[2]; |
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int channel_number = 0; |
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short *output_samples = data; |
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int shift[2]; |
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unsigned char byte; |
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short diff; |
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if (!buf_size) |
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return 0; |
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switch(avctx->codec->id) { |
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case CODEC_ID_ROQ_DPCM: |
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if (s->channels == 1) |
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predictor[0] = LE_16(&buf[6]); |
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else { |
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predictor[0] = buf[7] << 8; |
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predictor[1] = buf[6] << 8; |
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} |
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SE_16BIT(predictor[0]); |
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SE_16BIT(predictor[1]); |
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/* decode the samples */ |
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for (in = 8, out = 0; in < buf_size; in++, out++) { |
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predictor[channel_number] += s->roq_square_array[buf[in]]; |
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SATURATE_S16(predictor[channel_number]); |
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output_samples[out] = predictor[channel_number]; |
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/* toggle channel */ |
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channel_number ^= s->channels - 1; |
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} |
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break; |
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case CODEC_ID_INTERPLAY_DPCM: |
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in = 6; /* skip over the stream mask and stream length */ |
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predictor[0] = LE_16(&buf[in]); |
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in += 2; |
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SE_16BIT(predictor[0]) |
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output_samples[out++] = predictor[0]; |
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if (s->channels == 2) { |
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predictor[1] = LE_16(&buf[in]); |
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in += 2; |
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SE_16BIT(predictor[1]) |
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output_samples[out++] = predictor[1]; |
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} |
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while (in < buf_size) { |
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predictor[channel_number] += interplay_delta_table[buf[in++]]; |
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SATURATE_S16(predictor[channel_number]); |
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output_samples[out++] = predictor[channel_number]; |
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/* toggle channel */ |
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channel_number ^= s->channels - 1; |
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} |
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break; |
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case CODEC_ID_XAN_DPCM: |
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in = 0; |
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shift[0] = shift[1] = 4; |
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predictor[0] = LE_16(&buf[in]); |
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in += 2; |
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SE_16BIT(predictor[0]); |
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if (s->channels == 2) { |
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predictor[1] = LE_16(&buf[in]); |
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in += 2; |
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SE_16BIT(predictor[1]); |
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} |
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while (in < buf_size) { |
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byte = buf[in++]; |
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diff = (byte & 0xFC) << 8; |
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if ((byte & 0x03) == 3) |
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shift[channel_number]++; |
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else |
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shift[channel_number] -= (2 * (byte & 3)); |
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/* saturate the shifter to a lower limit of 0 */ |
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if (shift[channel_number] < 0) |
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shift[channel_number] = 0; |
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diff >>= shift[channel_number]; |
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predictor[channel_number] += diff; |
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SATURATE_S16(predictor[channel_number]); |
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output_samples[out++] = predictor[channel_number]; |
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/* toggle channel */ |
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channel_number ^= s->channels - 1; |
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} |
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break; |
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} |
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*data_size = out * sizeof(short); |
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return buf_size; |
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} |
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AVCodec roq_dpcm_decoder = { |
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"roq_dpcm", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_ROQ_DPCM, |
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sizeof(DPCMContext), |
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dpcm_decode_init, |
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NULL, |
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NULL, |
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dpcm_decode_frame, |
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}; |
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AVCodec interplay_dpcm_decoder = { |
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"interplay_dpcm", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_INTERPLAY_DPCM, |
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sizeof(DPCMContext), |
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dpcm_decode_init, |
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NULL, |
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NULL, |
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dpcm_decode_frame, |
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}; |
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AVCodec xan_dpcm_decoder = { |
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"xan_dpcm", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_XAN_DPCM, |
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sizeof(DPCMContext), |
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dpcm_decode_init, |
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NULL, |
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NULL, |
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dpcm_decode_frame, |
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};
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