diff options
Diffstat (limited to 'src/libmad/frame.c')
| -rw-r--r-- | src/libmad/frame.c | 503 |
1 files changed, 0 insertions, 503 deletions
diff --git a/src/libmad/frame.c b/src/libmad/frame.c index 0cb3d0f33..e69de29bb 100644 --- a/src/libmad/frame.c +++ b/src/libmad/frame.c @@ -1,503 +0,0 @@ -/* - * libmad - MPEG audio decoder library - * Copyright (C) 2000-2004 Underbit Technologies, Inc. - * - * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * - * $Id: frame.c,v 1.29 2004/02/04 22:59:19 rob Exp $ - */ - -# ifdef HAVE_CONFIG_H -# include "config.h" -# endif - -# include "global.h" - -# include <stdlib.h> - -# include "bit.h" -# include "stream.h" -# include "frame.h" -# include "timer.h" -# include "layer12.h" -# include "layer3.h" - -static -unsigned long const bitrate_table[5][15] = { - /* MPEG-1 */ - { 0, 32000, 64000, 96000, 128000, 160000, 192000, 224000, /* Layer I */ - 256000, 288000, 320000, 352000, 384000, 416000, 448000 }, - { 0, 32000, 48000, 56000, 64000, 80000, 96000, 112000, /* Layer II */ - 128000, 160000, 192000, 224000, 256000, 320000, 384000 }, - { 0, 32000, 40000, 48000, 56000, 64000, 80000, 96000, /* Layer III */ - 112000, 128000, 160000, 192000, 224000, 256000, 320000 }, - - /* MPEG-2 LSF */ - { 0, 32000, 48000, 56000, 64000, 80000, 96000, 112000, /* Layer I */ - 128000, 144000, 160000, 176000, 192000, 224000, 256000 }, - { 0, 8000, 16000, 24000, 32000, 40000, 48000, 56000, /* Layers */ - 64000, 80000, 96000, 112000, 128000, 144000, 160000 } /* II & III */ -}; - -static -unsigned int const samplerate_table[3] = { 44100, 48000, 32000 }; - -static -int (*const decoder_table[3])(struct mad_stream *, struct mad_frame *) = { - mad_layer_I, - mad_layer_II, - mad_layer_III -}; - -/* - * NAME: header->init() - * DESCRIPTION: initialize header struct - */ -void mad_header_init(struct mad_header *header) -{ - header->layer = 0; - header->mode = 0; - header->mode_extension = 0; - header->emphasis = 0; - - header->bitrate = 0; - header->samplerate = 0; - - header->crc_check = 0; - header->crc_target = 0; - - header->flags = 0; - header->private_bits = 0; - - header->duration = mad_timer_zero; -} - -/* - * NAME: frame->init() - * DESCRIPTION: initialize frame struct - */ -void mad_frame_init(struct mad_frame *frame) -{ - mad_header_init(&frame->header); - - frame->options = 0; - - frame->overlap = 0; - mad_frame_mute(frame); -} - -/* - * NAME: frame->finish() - * DESCRIPTION: deallocate any dynamic memory associated with frame - */ -void mad_frame_finish(struct mad_frame *frame) -{ - mad_header_finish(&frame->header); - - if (frame->overlap) { - free(frame->overlap); - frame->overlap = 0; - } -} - -/* - * NAME: decode_header() - * DESCRIPTION: read header data and following CRC word - */ -static -int decode_header(struct mad_header *header, struct mad_stream *stream) -{ - unsigned int index; - - header->flags = 0; - header->private_bits = 0; - - /* header() */ - - /* syncword */ - mad_bit_skip(&stream->ptr, 11); - - /* MPEG 2.5 indicator (really part of syncword) */ - if (mad_bit_read(&stream->ptr, 1) == 0) - header->flags |= MAD_FLAG_MPEG_2_5_EXT; - - /* ID */ - if (mad_bit_read(&stream->ptr, 1) == 0) - header->flags |= MAD_FLAG_LSF_EXT; - else if (header->flags & MAD_FLAG_MPEG_2_5_EXT) { - stream->error = MAD_ERROR_LOSTSYNC; - return -1; - } - - /* layer */ - header->layer = 4 - mad_bit_read(&stream->ptr, 2); - - if (header->layer == 4) { - stream->error = MAD_ERROR_BADLAYER; - return -1; - } - - /* protection_bit */ - if (mad_bit_read(&stream->ptr, 1) == 0) { - header->flags |= MAD_FLAG_PROTECTION; - header->crc_check = mad_bit_crc(stream->ptr, 16, 0xffff); - } - - /* bitrate_index */ - index = mad_bit_read(&stream->ptr, 4); - - if (index == 15) { - stream->error = MAD_ERROR_BADBITRATE; - return -1; - } - - if (header->flags & MAD_FLAG_LSF_EXT) - header->bitrate = bitrate_table[3 + (header->layer >> 1)][index]; - else - header->bitrate = bitrate_table[header->layer - 1][index]; - - /* sampling_frequency */ - index = mad_bit_read(&stream->ptr, 2); - - if (index == 3) { - stream->error = MAD_ERROR_BADSAMPLERATE; - return -1; - } - - header->samplerate = samplerate_table[index]; - - if (header->flags & MAD_FLAG_LSF_EXT) { - header->samplerate /= 2; - - if (header->flags & MAD_FLAG_MPEG_2_5_EXT) - header->samplerate /= 2; - } - - /* padding_bit */ - if (mad_bit_read(&stream->ptr, 1)) - header->flags |= MAD_FLAG_PADDING; - - /* private_bit */ - if (mad_bit_read(&stream->ptr, 1)) - header->private_bits |= MAD_PRIVATE_HEADER; - - /* mode */ - header->mode = 3 - mad_bit_read(&stream->ptr, 2); - - /* mode_extension */ - header->mode_extension = mad_bit_read(&stream->ptr, 2); - - /* copyright */ - if (mad_bit_read(&stream->ptr, 1)) - header->flags |= MAD_FLAG_COPYRIGHT; - - /* original/copy */ - if (mad_bit_read(&stream->ptr, 1)) - header->flags |= MAD_FLAG_ORIGINAL; - - /* emphasis */ - header->emphasis = mad_bit_read(&stream->ptr, 2); - -# if defined(OPT_STRICT) - /* - * ISO/IEC 11172-3 says this is a reserved emphasis value, but - * streams exist which use it anyway. Since the value is not important - * to the decoder proper, we allow it unless OPT_STRICT is defined. - */ - if (header->emphasis == MAD_EMPHASIS_RESERVED) { - stream->error = MAD_ERROR_BADEMPHASIS; - return -1; - } -# endif - - /* error_check() */ - - /* crc_check */ - if (header->flags & MAD_FLAG_PROTECTION) - header->crc_target = mad_bit_read(&stream->ptr, 16); - - return 0; -} - -/* - * NAME: free_bitrate() - * DESCRIPTION: attempt to discover the bitstream's free bitrate - */ -static -int free_bitrate(struct mad_stream *stream, struct mad_header const *header) -{ - struct mad_bitptr keep_ptr; - unsigned long rate = 0; - unsigned int pad_slot, slots_per_frame; - unsigned char const *ptr = 0; - - keep_ptr = stream->ptr; - - pad_slot = (header->flags & MAD_FLAG_PADDING) ? 1 : 0; - slots_per_frame = (header->layer == MAD_LAYER_III && - (header->flags & MAD_FLAG_LSF_EXT)) ? 72 : 144; - - while (mad_stream_sync(stream) == 0) { - struct mad_stream peek_stream; - struct mad_header peek_header; - - peek_stream = *stream; - peek_header = *header; - - if (decode_header(&peek_header, &peek_stream) == 0 && - peek_header.layer == header->layer && - peek_header.samplerate == header->samplerate) { - unsigned int N; - - ptr = mad_bit_nextbyte(&stream->ptr); - - N = ptr - stream->this_frame; - - if (header->layer == MAD_LAYER_I) { - rate = (unsigned long) header->samplerate * - (N - 4 * pad_slot + 4) / 48 / 1000; - } - else { - rate = (unsigned long) header->samplerate * - (N - pad_slot + 1) / slots_per_frame / 1000; - } - - if (rate >= 8) - break; - } - - mad_bit_skip(&stream->ptr, 8); - } - - stream->ptr = keep_ptr; - - if (rate < 8 || (header->layer == MAD_LAYER_III && rate > 640)) { - stream->error = MAD_ERROR_LOSTSYNC; - return -1; - } - - stream->freerate = rate * 1000; - - return 0; -} - -/* - * NAME: header->decode() - * DESCRIPTION: read the next frame header from the stream - */ -int mad_header_decode(struct mad_header *header, struct mad_stream *stream) -{ - register unsigned char const *ptr, *end; - unsigned int pad_slot, N; - - ptr = stream->next_frame; - end = stream->bufend; - - if (ptr == 0) { - stream->error = MAD_ERROR_BUFPTR; - goto fail; - } - - /* stream skip */ - if (stream->skiplen) { - if (!stream->sync) - ptr = stream->this_frame; - - if (end - ptr < stream->skiplen) { - stream->skiplen -= end - ptr; - stream->next_frame = end; - - stream->error = MAD_ERROR_BUFLEN; - goto fail; - } - - ptr += stream->skiplen; - stream->skiplen = 0; - - stream->sync = 1; - } - - sync: - /* synchronize */ - if (stream->sync) { - if (end - ptr < MAD_BUFFER_GUARD) { - stream->next_frame = ptr; - - stream->error = MAD_ERROR_BUFLEN; - goto fail; - } - else if (!(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0)) { - /* mark point where frame sync word was expected */ - stream->this_frame = ptr; - stream->next_frame = ptr + 1; - - stream->error = MAD_ERROR_LOSTSYNC; - goto fail; - } - } - else { - mad_bit_init(&stream->ptr, ptr); - - if (mad_stream_sync(stream) == -1) { - if (end - stream->next_frame >= MAD_BUFFER_GUARD) - stream->next_frame = end - MAD_BUFFER_GUARD; - - stream->error = MAD_ERROR_BUFLEN; - goto fail; - } - - ptr = mad_bit_nextbyte(&stream->ptr); - } - - /* begin processing */ - stream->this_frame = ptr; - stream->next_frame = ptr + 1; /* possibly bogus sync word */ - - mad_bit_init(&stream->ptr, stream->this_frame); - - if (decode_header(header, stream) == -1) - goto fail; - - /* calculate frame duration */ - mad_timer_set(&header->duration, 0, - 32 * MAD_NSBSAMPLES(header), header->samplerate); - - /* calculate free bit rate */ - if (header->bitrate == 0) { - if ((stream->freerate == 0 || !stream->sync || - (header->layer == MAD_LAYER_III && stream->freerate > 640000)) && - free_bitrate(stream, header) == -1) - goto fail; - - header->bitrate = stream->freerate; - header->flags |= MAD_FLAG_FREEFORMAT; - } - - /* calculate beginning of next frame */ - pad_slot = (header->flags & MAD_FLAG_PADDING) ? 1 : 0; - - if (header->layer == MAD_LAYER_I) - N = ((12 * header->bitrate / header->samplerate) + pad_slot) * 4; - else { - unsigned int slots_per_frame; - - slots_per_frame = (header->layer == MAD_LAYER_III && - (header->flags & MAD_FLAG_LSF_EXT)) ? 72 : 144; - - N = (slots_per_frame * header->bitrate / header->samplerate) + pad_slot; - } - - /* verify there is enough data left in buffer to decode this frame */ - if (N + MAD_BUFFER_GUARD > end - stream->this_frame) { - stream->next_frame = stream->this_frame; - - stream->error = MAD_ERROR_BUFLEN; - goto fail; - } - - stream->next_frame = stream->this_frame + N; - - if (!stream->sync) { - /* check that a valid frame header follows this frame */ - - ptr = stream->next_frame; - if (!(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0)) { - ptr = stream->next_frame = stream->this_frame + 1; - goto sync; - } - - stream->sync = 1; - } - - header->flags |= MAD_FLAG_INCOMPLETE; - - return 0; - - fail: - stream->sync = 0; - - return -1; -} - -/* - * NAME: frame->decode() - * DESCRIPTION: decode a single frame from a bitstream - */ -int mad_frame_decode(struct mad_frame *frame, struct mad_stream *stream) -{ - frame->options = stream->options; - - /* header() */ - /* error_check() */ - - if (!(frame->header.flags & MAD_FLAG_INCOMPLETE) && - mad_header_decode(&frame->header, stream) == -1) - goto fail; - - /* audio_data() */ - - frame->header.flags &= ~MAD_FLAG_INCOMPLETE; - - if (decoder_table[frame->header.layer - 1](stream, frame) == -1) { - if (!MAD_RECOVERABLE(stream->error)) - stream->next_frame = stream->this_frame; - - goto fail; - } - - /* ancillary_data() */ - - if (frame->header.layer != MAD_LAYER_III) { - struct mad_bitptr next_frame; - - mad_bit_init(&next_frame, stream->next_frame); - - stream->anc_ptr = stream->ptr; - stream->anc_bitlen = mad_bit_length(&stream->ptr, &next_frame); - - mad_bit_finish(&next_frame); - } - - return 0; - - fail: - stream->anc_bitlen = 0; - return -1; -} - -/* - * NAME: frame->mute() - * DESCRIPTION: zero all subband values so the frame becomes silent - */ -void mad_frame_mute(struct mad_frame *frame) -{ - unsigned int s, sb; - - for (s = 0; s < 36; ++s) { - for (sb = 0; sb < 32; ++sb) { - frame->sbsample[0][s][sb] = - frame->sbsample[1][s][sb] = 0; - } - } - - if (frame->overlap) { - for (s = 0; s < 18; ++s) { - for (sb = 0; sb < 32; ++sb) { - (*frame->overlap)[0][sb][s] = - (*frame->overlap)[1][sb][s] = 0; - } - } - } -} |