yading@10: /* yading@10: * MPEG-4 Audio common code yading@10: * Copyright (c) 2008 Baptiste Coudurier yading@10: * Copyright (c) 2009 Alex Converse yading@10: * yading@10: * This file is part of FFmpeg. yading@10: * yading@10: * FFmpeg is free software; you can redistribute it and/or yading@10: * modify it under the terms of the GNU Lesser General Public yading@10: * License as published by the Free Software Foundation; either yading@10: * version 2.1 of the License, or (at your option) any later version. yading@10: * yading@10: * FFmpeg is distributed in the hope that it will be useful, yading@10: * but WITHOUT ANY WARRANTY; without even the implied warranty of yading@10: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yading@10: * Lesser General Public License for more details. yading@10: * yading@10: * You should have received a copy of the GNU Lesser General Public yading@10: * License along with FFmpeg; if not, write to the Free Software yading@10: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA yading@10: */ yading@10: yading@10: #include "get_bits.h" yading@10: #include "put_bits.h" yading@10: #include "mpeg4audio.h" yading@10: yading@10: /** yading@10: * Parse MPEG-4 audio configuration for ALS object type. yading@10: * @param[in] gb bit reader context yading@10: * @param[in] c MPEG4AudioConfig structure to fill yading@10: * @return on success 0 is returned, otherwise a value < 0 yading@10: */ yading@10: static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c) yading@10: { yading@10: if (get_bits_left(gb) < 112) yading@10: return -1; yading@10: yading@10: if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0')) yading@10: return -1; yading@10: yading@10: // override AudioSpecificConfig channel configuration and sample rate yading@10: // which are buggy in old ALS conformance files yading@10: c->sample_rate = get_bits_long(gb, 32); yading@10: yading@10: // skip number of samples yading@10: skip_bits_long(gb, 32); yading@10: yading@10: // read number of channels yading@10: c->chan_config = 0; yading@10: c->channels = get_bits(gb, 16) + 1; yading@10: yading@10: return 0; yading@10: } yading@10: yading@10: /* XXX: make sure to update the copies in the different encoders if you change yading@10: * this table */ yading@10: const int avpriv_mpeg4audio_sample_rates[16] = { yading@10: 96000, 88200, 64000, 48000, 44100, 32000, yading@10: 24000, 22050, 16000, 12000, 11025, 8000, 7350 yading@10: }; yading@10: yading@10: const uint8_t ff_mpeg4audio_channels[8] = { yading@10: 0, 1, 2, 3, 4, 5, 6, 8 yading@10: }; yading@10: yading@10: static inline int get_object_type(GetBitContext *gb) yading@10: { yading@10: int object_type = get_bits(gb, 5); yading@10: if (object_type == AOT_ESCAPE) yading@10: object_type = 32 + get_bits(gb, 6); yading@10: return object_type; yading@10: } yading@10: yading@10: static inline int get_sample_rate(GetBitContext *gb, int *index) yading@10: { yading@10: *index = get_bits(gb, 4); yading@10: return *index == 0x0f ? get_bits(gb, 24) : yading@10: avpriv_mpeg4audio_sample_rates[*index]; yading@10: } yading@10: yading@10: int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, yading@10: int bit_size, int sync_extension) yading@10: { yading@10: GetBitContext gb; yading@10: int specific_config_bitindex; yading@10: yading@10: if (bit_size <= 0 || init_get_bits(&gb, buf, bit_size) < 0) yading@10: return AVERROR_INVALIDDATA; yading@10: c->object_type = get_object_type(&gb); yading@10: c->sample_rate = get_sample_rate(&gb, &c->sampling_index); yading@10: c->chan_config = get_bits(&gb, 4); yading@10: if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels)) yading@10: c->channels = ff_mpeg4audio_channels[c->chan_config]; yading@10: c->sbr = -1; yading@10: c->ps = -1; yading@10: if (c->object_type == AOT_SBR || (c->object_type == AOT_PS && yading@10: // check for W6132 Annex YYYY draft MP3onMP4 yading@10: !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) { yading@10: if (c->object_type == AOT_PS) yading@10: c->ps = 1; yading@10: c->ext_object_type = AOT_SBR; yading@10: c->sbr = 1; yading@10: c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); yading@10: c->object_type = get_object_type(&gb); yading@10: if (c->object_type == AOT_ER_BSAC) yading@10: c->ext_chan_config = get_bits(&gb, 4); yading@10: } else { yading@10: c->ext_object_type = AOT_NULL; yading@10: c->ext_sample_rate = 0; yading@10: } yading@10: specific_config_bitindex = get_bits_count(&gb); yading@10: yading@10: if (c->object_type == AOT_ALS) { yading@10: skip_bits(&gb, 5); yading@10: if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S')) yading@10: skip_bits_long(&gb, 24); yading@10: yading@10: specific_config_bitindex = get_bits_count(&gb); yading@10: yading@10: if (parse_config_ALS(&gb, c)) yading@10: return -1; yading@10: } yading@10: yading@10: if (c->ext_object_type != AOT_SBR && sync_extension) { yading@10: while (get_bits_left(&gb) > 15) { yading@10: if (show_bits(&gb, 11) == 0x2b7) { // sync extension yading@10: get_bits(&gb, 11); yading@10: c->ext_object_type = get_object_type(&gb); yading@10: if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) { yading@10: c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); yading@10: if (c->ext_sample_rate == c->sample_rate) yading@10: c->sbr = -1; yading@10: } yading@10: if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548) yading@10: c->ps = get_bits1(&gb); yading@10: break; yading@10: } else yading@10: get_bits1(&gb); // skip 1 bit yading@10: } yading@10: } yading@10: yading@10: //PS requires SBR yading@10: if (!c->sbr) yading@10: c->ps = 0; yading@10: //Limit implicit PS to the HE-AACv2 Profile yading@10: if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01) yading@10: c->ps = 0; yading@10: yading@10: return specific_config_bitindex; yading@10: } yading@10: yading@10: static av_always_inline unsigned int copy_bits(PutBitContext *pb, yading@10: GetBitContext *gb, yading@10: int bits) yading@10: { yading@10: unsigned int el = get_bits(gb, bits); yading@10: put_bits(pb, bits, el); yading@10: return el; yading@10: } yading@10: yading@10: int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb) yading@10: { yading@10: int five_bit_ch, four_bit_ch, comment_size, bits; yading@10: int offset = put_bits_count(pb); yading@10: yading@10: copy_bits(pb, gb, 10); //Tag, Object Type, Frequency yading@10: five_bit_ch = copy_bits(pb, gb, 4); //Front yading@10: five_bit_ch += copy_bits(pb, gb, 4); //Side yading@10: five_bit_ch += copy_bits(pb, gb, 4); //Back yading@10: four_bit_ch = copy_bits(pb, gb, 2); //LFE yading@10: four_bit_ch += copy_bits(pb, gb, 3); //Data yading@10: five_bit_ch += copy_bits(pb, gb, 4); //Coupling yading@10: if (copy_bits(pb, gb, 1)) //Mono Mixdown yading@10: copy_bits(pb, gb, 4); yading@10: if (copy_bits(pb, gb, 1)) //Stereo Mixdown yading@10: copy_bits(pb, gb, 4); yading@10: if (copy_bits(pb, gb, 1)) //Matrix Mixdown yading@10: copy_bits(pb, gb, 3); yading@10: for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16) yading@10: copy_bits(pb, gb, 16); yading@10: if (bits) yading@10: copy_bits(pb, gb, bits); yading@10: avpriv_align_put_bits(pb); yading@10: align_get_bits(gb); yading@10: comment_size = copy_bits(pb, gb, 8); yading@10: for (; comment_size > 0; comment_size--) yading@10: copy_bits(pb, gb, 8); yading@10: yading@10: return put_bits_count(pb) - offset; yading@10: }