/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * * Copyright (C) 2005 Dave Chapman * * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "codeclib.h" #include CODEC_HEADER static FLACContext fc IBSS_ATTR_FLAC; /* The output buffers containing the decoded samples (channels 0 and 1) */ static int32_t decoded0[MAX_BLOCKSIZE] IBSS_ATTR_FLAC; static int32_t decoded1[MAX_BLOCKSIZE] IBSS_ATTR_FLAC; static int32_t decoded2[MAX_BLOCKSIZE] IBSS_ATTR_FLAC_LARGE_IRAM; static int32_t decoded3[MAX_BLOCKSIZE] IBSS_ATTR_FLAC_LARGE_IRAM; static int32_t decoded4[MAX_BLOCKSIZE] IBSS_ATTR_FLAC_XLARGE_IRAM; static int32_t decoded5[MAX_BLOCKSIZE] IBSS_ATTR_FLAC_XLARGE_IRAM; static int32_t decoded6[MAX_BLOCKSIZE] IBSS_ATTR_FLAC_XXLARGE_IRAM; #define MAX_SUPPORTED_SEEKTABLE_SIZE 5000 /* Notes about seeking: The full seek table consists of: uint64_t sample (only 36 bits are used) uint64_t offset uint32_t blocksize We also limit the sample and offset values to 32-bits - Rockbox doesn't support files bigger than 2GB on FAT32 filesystems. The reference FLAC encoder produces a seek table with points every 10 seconds, but this can be overridden by the user when encoding a file. With the default settings, a typical 4 minute track will contain 24 seek points. Taking the extreme case of a Rockbox supported file to be a 2GB (compressed) 16-bit/44.1KHz mono stream with a likely uncompressed size of 4GB: Total duration is: 48694 seconds (about 810 minutes - 13.5 hours) Total number of seek points: 4869 Therefore we limit the number of seek points to 5000. This is a very extreme case, and requires 5000*8=40000 bytes of storage. If we come across a FLAC file with more than this number of seekpoints, we just use the first 5000. */ struct FLACseekpoints { uint32_t sample; uint32_t offset; uint16_t blocksize; }; static struct FLACseekpoints seekpoints[MAX_SUPPORTED_SEEKTABLE_SIZE]; static int nseekpoints; static int8_t *bit_buffer; static size_t buff_size; static bool flac_init(FLACContext* fc, int first_frame_offset) { unsigned char buf[255]; bool found_streaminfo=false; uint32_t seekpoint_hi,seekpoint_lo; uint32_t offset_hi,offset_lo; uint16_t blocksize; int endofmetadata=0; uint32_t blocklength; ci->memset(fc,0,sizeof(FLACContext)); nseekpoints=0; fc->sample_skip = 0; /* Reset sample buffers */ ci->memset(decoded0, 0, sizeof(decoded0)); ci->memset(decoded1, 0, sizeof(decoded1)); ci->memset(decoded2, 0, sizeof(decoded2)); ci->memset(decoded3, 0, sizeof(decoded3)); ci->memset(decoded4, 0, sizeof(decoded4)); ci->memset(decoded5, 0, sizeof(decoded5)); ci->memset(decoded6, 0, sizeof(decoded5)); /* Set sample buffers in decoder structure */ fc->decoded[0] = decoded0; fc->decoded[1] = decoded1; fc->decoded[2] = decoded2; fc->decoded[3] = decoded3; fc->decoded[4] = decoded4; fc->decoded[5] = decoded5; fc->decoded[6] = decoded6; /* Skip any foreign tags at start of file */ ci->seek_buffer(first_frame_offset); fc->metadatalength = first_frame_offset; if (ci->read_filebuf(buf, 4) < 4) { return false; } if (ci->memcmp(buf,"fLaC",4) != 0) { return false; } fc->metadatalength += 4; while (!endofmetadata) { if (ci->read_filebuf(buf, 4) < 4) { return false; } endofmetadata=(buf[0]&0x80); blocklength = (buf[1] << 16) | (buf[2] << 8) | buf[3]; fc->metadatalength+=blocklength+4; if ((buf[0] & 0x7f) == 0) /* 0 is the STREAMINFO block */ { if (ci->read_filebuf(buf, blocklength) < blocklength) return false; fc->filesize = ci->filesize; fc->min_blocksize = (buf[0] << 8) | buf[1]; int max_blocksize = (buf[2] << 8) | buf[3]; if (max_blocksize > MAX_BLOCKSIZE) { LOGF("FLAC: Maximum blocksize is too large (%d > %d)\n", max_blocksize, MAX_BLOCKSIZE); return false; } fc->max_blocksize = max_blocksize; fc->min_framesize = (buf[4] << 16) | (buf[5] << 8) | buf[6]; fc->max_framesize = (buf[7] << 16) | (buf[8] << 8) | buf[9]; fc->samplerate = (buf[10] << 12) | (buf[11] << 4) | ((buf[12] & 0xf0) >> 4); fc->channels = ((buf[12]&0x0e)>>1) + 1; fc->bps = (((buf[12]&0x01) << 4) | ((buf[13]&0xf0)>>4) ) + 1; if (fc->channels > MAX_CHANNELS) { LOGF("FLAC: Too many channels (%d > %d)\n", fc->channels, MAX_CHANNELS); return false; } /* totalsamples is a 36-bit field, but we assume <= 32 bits are used */ fc->totalsamples = (buf[14] << 24) | (buf[15] << 16) | (buf[16] << 8) | buf[17]; /* Calculate track length (in ms) and estimate the bitrate (in kbit/s) */ fc->length = ((int64_t) fc->totalsamples * 1000) / fc->samplerate; found_streaminfo=true; } else if ((buf[0] & 0x7f) == 3) { /* 3 is the SEEKTABLE block */ while ((nseekpoints < MAX_SUPPORTED_SEEKTABLE_SIZE) && (blocklength >= 18)) { if (ci->read_filebuf(buf,18) < 18) return false; blocklength-=18; seekpoint_hi=(buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]; seekpoint_lo=(buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7]; offset_hi=(buf[8] << 24) | (buf[9] << 16) | (buf[10] << 8) | buf[11]; offset_lo=(buf[12] << 24) | (buf[13] << 16) | (buf[14] << 8) | buf[15]; blocksize=(buf[16] << 8) | buf[17]; /* Only store seekpoints where the high 32 bits are zero */ if ((seekpoint_hi == 0) && (seekpoint_lo != 0xffffffff) && (offset_hi == 0)) { seekpoints[nseekpoints].sample=seekpoint_lo; seekpoints[nseekpoints].offset=offset_lo; seekpoints[nseekpoints].blocksize=blocksize; nseekpoints++; } } /* Skip any unread seekpoints */ if (blocklength > 0) ci->advance_buffer(blocklength); } else { /* Skip to next metadata block */ ci->advance_buffer(blocklength); } } if (found_streaminfo) { fc->bitrate = ((int64_t) (fc->filesize-fc->metadatalength) * 8) / fc->length; return true; } else { return false; } } /* Synchronize to next frame in stream - adapted from libFLAC 1.1.3b2 */ static bool frame_sync(FLACContext* fc) { unsigned int x = 0; bool cached = false; /* Make sure we're byte aligned. */ align_get_bits(&fc->gb); while(1) { if(fc->gb.size_in_bits - get_bits_count(&fc->gb) < 8) { /* Error, end of bitstream, a valid stream should never reach here * since the buffer should contain at least one frame header. */ return false; } if(cached) cached = false; else x = get_bits(&fc->gb, 8); if(x == 0xff) { /* MAGIC NUMBER for first 8 frame sync bits. */ x = get_bits(&fc->gb, 8); /* We have to check if we just read two 0xff's in a row; the second * may actually be the beginning of the sync code. */ if(x == 0xff) { /* MAGIC NUMBER for first 8 frame sync bits. */ cached = true; } else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for last 6 sync bits. */ /* Succesfully synced. */ break; } } } /* Advance and init bit buffer to the new frame. */ ci->advance_buffer((get_bits_count(&fc->gb)-16)>>3); /* consumed bytes */ bit_buffer = ci->request_buffer(&buff_size, MAX_FRAMESIZE+16); init_get_bits(&fc->gb, bit_buffer, buff_size*8); /* Decode the frame to verify the frame crc and * fill fc with its metadata. */ if(flac_decode_frame(fc, bit_buffer, buff_size, ci->yield) < 0) { return false; } return true; } /* Seek to sample - adapted from libFLAC 1.1.3b2+ */ static bool flac_seek(FLACContext* fc, uint32_t target_sample) { off_t orig_pos = ci->curpos; off_t pos = -1; unsigned long lower_bound, upper_bound; unsigned long lower_bound_sample, upper_bound_sample; int i; unsigned approx_bytes_per_frame; uint32_t this_frame_sample = fc->samplenumber; unsigned this_block_size = fc->blocksize; bool needs_seek = true, first_seek = true; /* We are just guessing here. */ if(fc->max_framesize > 0) approx_bytes_per_frame = (fc->max_framesize + fc->min_framesize)/2 + 1; /* Check if it's a known fixed-blocksize stream. */ else if(fc->min_blocksize == fc->max_blocksize && fc->min_blocksize > 0) approx_bytes_per_frame = fc->min_blocksize*fc->channels*fc->bps/8 + 64; else approx_bytes_per_frame = 4608 * fc->channels * fc->bps/8 + 64; /* Set an upper and lower bound on where in the stream we will search. */ lower_bound = fc->metadatalength; lower_bound_sample = 0; upper_bound = fc->filesize; upper_bound_sample = fc->totalsamples>0 ? fc->totalsamples : target_sample; /* Refine the bounds if we have a seektable with suitable points. */ if(nseekpoints > 0) { /* Find the closest seek point <= target_sample, if it exists. */ for(i = nseekpoints-1; i >= 0; i--) { if(seekpoints[i].sample <= target_sample) break; } if(i >= 0) { /* i.e. we found a suitable seek point... */ lower_bound = fc->metadatalength + seekpoints[i].offset; lower_bound_sample = seekpoints[i].sample; } /* Find the closest seek point > target_sample, if it exists. */ for(i = 0; i < nseekpoints; i++) { if(seekpoints[i].sample > target_sample) break; } if(i < nseekpoints) { /* i.e. we found a suitable seek point... */ upper_bound = fc->metadatalength + seekpoints[i].offset; upper_bound_sample = seekpoints[i].sample; } } while(1) { /* Check if bounds are still ok. */ if(lower_bound_sample >= upper_bound_sample || lower_bound > upper_bound) { return false; } /* Calculate new seek position */ if(needs_seek) { pos = (off_t)(lower_bound + (((target_sample - lower_bound_sample) * (int64_t)(upper_bound - lower_bound)) / (upper_bound_sample - lower_bound_sample)) - approx_bytes_per_frame); if(pos >= (off_t)upper_bound) pos = (off_t)upper_bound-1; if(pos < (off_t)lower_bound) pos = (off_t)lower_bound; } if(!ci->seek_buffer(pos)) return false; bit_buffer = ci->request_buffer(&buff_size, MAX_FRAMESIZE+16); init_get_bits(&fc->gb, bit_buffer, buff_size*8); /* Now we need to get a frame. It is possible for our seek * to land in the middle of audio data that looks exactly like * a frame header from a future version of an encoder. When * that happens, frame_sync() will return false. * But there is a remote possibility that it is properly * synced at such a "future-codec frame", so to make sure, * we wait to see several "unparseable" errors in a row before * bailing out. */ { unsigned unparseable_count; bool got_a_frame = false; for(unparseable_count = 0; !got_a_frame && unparseable_count < 30; unparseable_count++) { if(frame_sync(fc)) got_a_frame = true; } if(!got_a_frame) { ci->seek_buffer(orig_pos); return false; } } this_frame_sample = fc->samplenumber; this_block_size = fc->blocksize; if(target_sample >= this_frame_sample && target_sample < this_frame_sample+this_block_size) { /* Found the frame containing the target sample. */ fc->sample_skip = target_sample - this_frame_sample; break; } if(this_frame_sample + this_block_size >= upper_bound_sample && !first_seek) { if(pos == (off_t)lower_bound || !needs_seek) { ci->seek_buffer(orig_pos); return false; } /* Our last move backwards wasn't big enough, try again. */ approx_bytes_per_frame *= 2; continue; } /* Allow one seek over upper bound, * required for streams with unknown total samples. */ first_seek = false; /* Make sure we are not seeking in a corrupted stream */ if(this_frame_sample < lower_bound_sample) { ci->seek_buffer(orig_pos); return false; } approx_bytes_per_frame = this_block_size*fc->channels*fc->bps/8 + 64; /* We need to narrow the search. */ if(target_sample < this_frame_sample) { upper_bound_sample = this_frame_sample; upper_bound = ci->curpos; } else { /* Target is beyond this frame. */ /* We are close, continue in decoding next frames. */ if(target_sample < this_frame_sample + 4*this_block_size) { pos = ci->curpos + fc->framesize; needs_seek = false; } lower_bound_sample = this_frame_sample + this_block_size; lower_bound = ci->curpos + fc->framesize; } } return true; } /* Seek to file offset */ static bool flac_seek_offset(FLACContext* fc, uint32_t offset) { unsigned unparseable_count; bool got_a_frame = false; if(!ci->seek_buffer(offset)) return false; bit_buffer = ci->request_buffer(&buff_size, MAX_FRAMESIZE); init_get_bits(&fc->gb, bit_buffer, buff_size*8); for(unparseable_count = 0; !got_a_frame && unparseable_count < 10; unparseable_count++) { if(frame_sync(fc)) got_a_frame = true; } if(!got_a_frame) { ci->seek_buffer(fc->metadatalength); return false; } return true; } /* this is the codec entry point */ enum codec_status codec_main(enum codec_entry_call_reason reason) { if (reason == CODEC_LOAD) { /* Generic codec initialisation */ ci->configure(DSP_SET_SAMPLE_DEPTH, FLAC_OUTPUT_DEPTH-1); } return CODEC_OK; } /* this is called for each file to process */ enum codec_status codec_run(void) { int8_t *buf; uint32_t samplesdone; uint32_t elapsedtime; size_t bytesleft; int consumed; int res; #if defined(LOGF_ENABLE) int frame = 0; #endif intptr_t param; if (codec_init()) { LOGF("FLAC: Error initialising codec\n"); return CODEC_ERROR; } /* Need to save resume for later use (cleared indirectly by flac_init) */ elapsedtime = ci->id3->elapsed; samplesdone = ci->id3->offset; if (!flac_init(&fc,ci->id3->first_frame_offset)) { LOGF("FLAC: Error initialising codec\n"); return CODEC_ERROR; } ci->configure(DSP_SET_FREQUENCY, ci->id3->frequency); ci->configure(DSP_SET_STEREO_MODE, fc.channels == 1 ? STEREO_MONO : STEREO_NONINTERLEAVED); codec_set_replaygain(ci->id3); if (samplesdone || !elapsedtime) { flac_seek_offset(&fc, samplesdone); samplesdone=fc.samplenumber+fc.blocksize; elapsedtime=((uint64_t)samplesdone*1000)/(ci->id3->frequency); } else if (!flac_seek(&fc,(uint32_t)((uint64_t)elapsedtime *ci->id3->frequency/1000))) { elapsedtime = 0; } ci->set_elapsed(elapsedtime); /* The main decoding loop */ buf = ci->request_buffer(&bytesleft, MAX_FRAMESIZE); while (bytesleft) { long action = ci->get_command(¶m); if (action == CODEC_ACTION_HALT) break; /* Deal with any pending seek requests */ if (action == CODEC_ACTION_SEEK_TIME) { if (flac_seek(&fc,(uint32_t)(((uint64_t)param *ci->id3->frequency)/1000))) { /* Refill the input buffer */ buf = ci->request_buffer(&bytesleft, MAX_FRAMESIZE); } ci->set_elapsed(param); ci->seek_complete(); } if((res=flac_decode_frame(&fc,buf, bytesleft,ci->yield)) < 0) { LOGF("FLAC: Frame %d, error %d\n",frame,res); return CODEC_ERROR; } consumed=fc.gb.index/8; #if defined(LOGF_ENABLE) frame++; #endif ci->yield(); ci->pcmbuf_insert(&fc.decoded[0][fc.sample_skip], &fc.decoded[1][fc.sample_skip], fc.blocksize - fc.sample_skip); fc.sample_skip = 0; /* Update the elapsed-time indicator */ samplesdone=fc.samplenumber+fc.blocksize; elapsedtime=((uint64_t)samplesdone*1000)/(ci->id3->frequency); ci->set_elapsed(elapsedtime); ci->advance_buffer(consumed); buf = ci->request_buffer(&bytesleft, MAX_FRAMESIZE); } LOGF("FLAC: Decoded %lu samples\n",(unsigned long)samplesdone); return CODEC_OK; }