/* * DK3 ADPCM decoder * * "This format number was used by Duck Corp. but not officially * registered with Microsoft" * * This file is responsible for decoding audio data encoded with * Duck Corp's DK3 ADPCM algorithm. Details about the data format * can be found here: * http://www.pcisys.net/~melanson/codecs/ * * Copyright (c) 2002 Mike Melanson * * This file is part of MPlayer. * * MPlayer is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * MPlayer 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 General Public License for more details. * * You should have received a copy of the GNU General Public License along * with MPlayer; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include #include #include #include #include "config.h" #include "ad_internal.h" static const ad_info_t info = { "Duck Corp. DK3 ADPCM decoder", "dk3adpcm", "Nick Kurshev", "Mike Melanson", "" }; LIBAD_EXTERN(dk3adpcm) #define DK3_ADPCM_PREAMBLE_SIZE 16 // useful macros // clamp a number between 0 and 88 #define CLAMP_0_TO_88(x) if (x < 0) x = 0; else if (x > 88) x = 88; // clamp a number within a signed 16-bit range #define CLAMP_S16(x) if (x < -32768) x = -32768; \ else if (x > 32767) x = 32767; // clamp a number above 16 #define CLAMP_ABOVE_16(x) if (x < 16) x = 16; // sign extend a 16-bit value #define SE_16BIT(x) if (x & 0x8000) x -= 0x10000; // sign extend a 4-bit value #define SE_4BIT(x) if (x & 0x8) x -= 0x10; // pertinent tables static int adpcm_step[89] = { 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767 }; static int adpcm_index[16] = { -1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8 }; static int preinit(sh_audio_t *sh_audio) { sh_audio->audio_out_minsize = sh_audio->wf->nBlockAlign * 6; sh_audio->ds->ss_div = (sh_audio->wf->nBlockAlign - DK3_ADPCM_PREAMBLE_SIZE) * 8 / 3; sh_audio->audio_in_minsize= sh_audio->ds->ss_mul = sh_audio->wf->nBlockAlign; return 1; } static int init(sh_audio_t *sh_audio) { sh_audio->channels = sh_audio->wf->nChannels; sh_audio->samplerate = sh_audio->wf->nSamplesPerSec; sh_audio->i_bps = (sh_audio->ds->ss_mul * sh_audio->samplerate) / sh_audio->ds->ss_div; sh_audio->samplesize=2; return 1; } static void uninit(sh_audio_t *sh_audio) { } static int control(sh_audio_t *sh_audio,int cmd,void* arg, ...) { if(cmd==ADCTRL_SKIP_FRAME){ demux_read_data(sh_audio->ds, sh_audio->a_in_buffer,sh_audio->ds->ss_mul); return CONTROL_TRUE; } return CONTROL_UNKNOWN; } #define DK3_GET_NEXT_NIBBLE() \ if (decode_top_nibble_next) \ { \ nibble = (last_byte >> 4) & 0x0F; \ decode_top_nibble_next = 0; \ } \ else \ { \ last_byte = input[in_ptr++]; \ nibble = last_byte & 0x0F; \ decode_top_nibble_next = 1; \ } // note: This decoder assumes the format 0x62 data always comes in // stereo flavor static int dk3_adpcm_decode_block(unsigned short *output, unsigned char *input, int block_size) { int sum_pred; int diff_pred; int sum_index; int diff_index; int diff_channel; int in_ptr = 0x10; int out_ptr = 0; unsigned char last_byte = 0; unsigned char nibble; int decode_top_nibble_next = 0; // ADPCM work variables int sign; int delta; int step; int diff; sum_pred = AV_RL16(&input[10]); diff_pred = AV_RL16(&input[12]); SE_16BIT(sum_pred); SE_16BIT(diff_pred); diff_channel = diff_pred; sum_index = input[14]; diff_index = input[15]; while (in_ptr < block_size - !decode_top_nibble_next) // while (in_ptr < 2048) { // process the first predictor of the sum channel DK3_GET_NEXT_NIBBLE(); step = adpcm_step[sum_index]; sign = nibble & 8; delta = nibble & 7; diff = step >> 3; if (delta & 4) diff += step; if (delta & 2) diff += step >> 1; if (delta & 1) diff += step >> 2; if (sign) sum_pred -= diff; else sum_pred += diff; CLAMP_S16(sum_pred); sum_index += adpcm_index[nibble]; CLAMP_0_TO_88(sum_index); // process the diff channel predictor DK3_GET_NEXT_NIBBLE(); step = adpcm_step[diff_index]; sign = nibble & 8; delta = nibble & 7; diff = step >> 3; if (delta & 4) diff += step; if (delta & 2) diff += step >> 1; if (delta & 1) diff += step >> 2; if (sign) diff_pred -= diff; else diff_pred += diff; CLAMP_S16(diff_pred); diff_index += adpcm_index[nibble]; CLAMP_0_TO_88(diff_index); // output the first pair of stereo PCM samples diff_channel = (diff_channel + diff_pred) / 2; output[out_ptr++] = sum_pred + diff_channel; output[out_ptr++] = sum_pred - diff_channel; // process the second predictor of the sum channel DK3_GET_NEXT_NIBBLE(); step = adpcm_step[sum_index]; sign = nibble & 8; delta = nibble & 7; diff = step >> 3; if (delta & 4) diff += step; if (delta & 2) diff += step >> 1; if (delta & 1) diff += step >> 2; if (sign) sum_pred -= diff; else sum_pred += diff; CLAMP_S16(sum_pred); sum_index += adpcm_index[nibble]; CLAMP_0_TO_88(sum_index); // output the second pair of stereo PCM samples output[out_ptr++] = sum_pred + diff_channel; output[out_ptr++] = sum_pred - diff_channel; } return out_ptr; } static int decode_audio(sh_audio_t *sh_audio,unsigned char *buf,int minlen,int maxlen) { if (demux_read_data(sh_audio->ds, sh_audio->a_in_buffer, sh_audio->ds->ss_mul) != sh_audio->ds->ss_mul) return -1; /* EOF */ if (maxlen < 2 * 4 * sh_audio->wf->nBlockAlign * 2 / 3) { mp_msg(MSGT_DECAUDIO, MSGL_V, "dk3adpcm: maxlen too small in decode_audio\n"); return -1; } return 2 * dk3_adpcm_decode_block( (unsigned short*)buf, sh_audio->a_in_buffer, sh_audio->ds->ss_mul); }