/* libdemac - A Monkey's Audio decoder Copyright (C) Dave Chapman 2007 This program 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. This program 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 this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA */ #include #include #include "demac.h" #include "predictor.h" #include "entropy.h" #include "filter.h" #include "demac_config.h" /* Statically allocate the filter buffers */ #ifdef FILTER256_IRAM static filter_int filterbuf32[(32*3 + FILTER_HISTORY_SIZE) * 2] IBSS_ATTR_DEMAC MEM_ALIGN_ATTR; /* 2432 or 4864 bytes */ static filter_int filterbuf256[(256*3 + FILTER_HISTORY_SIZE) * 2] IBSS_ATTR_DEMAC MEM_ALIGN_ATTR; /* 5120 or 10240 bytes */ #define FILTERBUF64 filterbuf256 #define FILTERBUF32 filterbuf32 #define FILTERBUF16 filterbuf32 #else static filter_int filterbuf64[(64*3 + FILTER_HISTORY_SIZE) * 2] IBSS_ATTR_DEMAC MEM_ALIGN_ATTR; /* 2432 or 4864 bytes */ static filter_int filterbuf256[(256*3 + FILTER_HISTORY_SIZE) * 2] MEM_ALIGN_ATTR; /* 5120 or 10240 bytes */ #define FILTERBUF64 filterbuf64 #define FILTERBUF32 filterbuf64 #define FILTERBUF16 filterbuf64 #endif /* This is only needed for "insane" files, and no current Rockbox targets can hope to decode them in realtime, except the Gigabeat S (at 528MHz). */ static filter_int filterbuf1280[(1280*3 + FILTER_HISTORY_SIZE) * 2] IBSS_ATTR_DEMAC_INSANEBUF MEM_ALIGN_ATTR; /* 17408 or 34816 bytes */ void init_frame_decoder(struct ape_ctx_t* ape_ctx, unsigned char* inbuffer, int* firstbyte, int* bytesconsumed) { init_entropy_decoder(ape_ctx, inbuffer, firstbyte, bytesconsumed); //printf("CRC=0x%08x\n",ape_ctx->CRC); //printf("Flags=0x%08x\n",ape_ctx->frameflags); init_predictor_decoder(&ape_ctx->predictor); switch (ape_ctx->compressiontype) { case 2000: init_filter_16_11(FILTERBUF16); break; case 3000: init_filter_64_11(FILTERBUF64); break; case 4000: init_filter_256_13(filterbuf256); init_filter_32_10(FILTERBUF32); break; case 5000: init_filter_1280_15(filterbuf1280); init_filter_256_13(filterbuf256); init_filter_16_11(FILTERBUF32); } } int ICODE_ATTR_DEMAC decode_chunk(struct ape_ctx_t* ape_ctx, unsigned char* inbuffer, int* firstbyte, int* bytesconsumed, int32_t* decoded0, int32_t* decoded1, int count) { int32_t left, right; #ifdef ROCKBOX int scale = (APE_OUTPUT_DEPTH - ape_ctx->bps); #define SCALE(x) ((x) << scale) #else #define SCALE(x) (x) #endif if ((ape_ctx->channels==1) || ((ape_ctx->frameflags & (APE_FRAMECODE_PSEUDO_STEREO|APE_FRAMECODE_STEREO_SILENCE)) == APE_FRAMECODE_PSEUDO_STEREO)) { entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed, decoded0, NULL, count); if (ape_ctx->frameflags & APE_FRAMECODE_MONO_SILENCE) { /* We are pure silence, so we're done. */ return 0; } switch (ape_ctx->compressiontype) { case 2000: apply_filter_16_11(ape_ctx->fileversion,0,decoded0,count); break; case 3000: apply_filter_64_11(ape_ctx->fileversion,0,decoded0,count); break; case 4000: apply_filter_32_10(ape_ctx->fileversion,0,decoded0,count); apply_filter_256_13(ape_ctx->fileversion,0,decoded0,count); break; case 5000: apply_filter_16_11(ape_ctx->fileversion,0,decoded0,count); apply_filter_256_13(ape_ctx->fileversion,0,decoded0,count); apply_filter_1280_15(ape_ctx->fileversion,0,decoded0,count); } /* Now apply the predictor decoding */ predictor_decode_mono(&ape_ctx->predictor,decoded0,count); if (ape_ctx->channels==2) { /* Pseudo-stereo - copy left channel to right channel */ while (count--) { left = *decoded0; *(decoded1++) = *(decoded0++) = SCALE(left); } } #ifdef ROCKBOX else { /* Scale to output depth */ while (count--) { left = *decoded0; *(decoded0++) = SCALE(left); } } #endif } else { /* Stereo */ entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed, decoded0, decoded1, count); if ((ape_ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) == APE_FRAMECODE_STEREO_SILENCE) { /* We are pure silence, so we're done. */ return 0; } /* Apply filters - compression type 1000 doesn't have any */ switch (ape_ctx->compressiontype) { case 2000: apply_filter_16_11(ape_ctx->fileversion,0,decoded0,count); apply_filter_16_11(ape_ctx->fileversion,1,decoded1,count); break; case 3000: apply_filter_64_11(ape_ctx->fileversion,0,decoded0,count); apply_filter_64_11(ape_ctx->fileversion,1,decoded1,count); break; case 4000: apply_filter_32_10(ape_ctx->fileversion,0,decoded0,count); apply_filter_32_10(ape_ctx->fileversion,1,decoded1,count); apply_filter_256_13(ape_ctx->fileversion,0,decoded0,count); apply_filter_256_13(ape_ctx->fileversion,1,decoded1,count); break; case 5000: apply_filter_16_11(ape_ctx->fileversion,0,decoded0,count); apply_filter_16_11(ape_ctx->fileversion,1,decoded1,count); apply_filter_256_13(ape_ctx->fileversion,0,decoded0,count); apply_filter_256_13(ape_ctx->fileversion,1,decoded1,count); apply_filter_1280_15(ape_ctx->fileversion,0,decoded0,count); apply_filter_1280_15(ape_ctx->fileversion,1,decoded1,count); } /* Now apply the predictor decoding */ predictor_decode_stereo(&ape_ctx->predictor,decoded0,decoded1,count); /* Decorrelate and scale to output depth */ while (count--) { left = *decoded1 - (*decoded0 / 2); right = left + *decoded0; *(decoded0++) = SCALE(left); *(decoded1++) = SCALE(right); } } return 0; }