diff options
Diffstat (limited to 'ffmpeg1/libavcodec/mpeg4audio.c')
| -rw-r--r-- | ffmpeg1/libavcodec/mpeg4audio.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/mpeg4audio.c b/ffmpeg1/libavcodec/mpeg4audio.c new file mode 100644 index 0000000..68448e6 --- /dev/null +++ b/ffmpeg1/libavcodec/mpeg4audio.c @@ -0,0 +1,190 @@ +/* + * MPEG-4 Audio common code + * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr> + * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com> + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "get_bits.h" +#include "put_bits.h" +#include "mpeg4audio.h" + +/** + * Parse MPEG-4 audio configuration for ALS object type. + * @param[in] gb bit reader context + * @param[in] c MPEG4AudioConfig structure to fill + * @return on success 0 is returned, otherwise a value < 0 + */ +static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c) +{ + if (get_bits_left(gb) < 112) + return -1; + + if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0')) + return -1; + + // override AudioSpecificConfig channel configuration and sample rate + // which are buggy in old ALS conformance files + c->sample_rate = get_bits_long(gb, 32); + + // skip number of samples + skip_bits_long(gb, 32); + + // read number of channels + c->chan_config = 0; + c->channels = get_bits(gb, 16) + 1; + + return 0; +} + +/* XXX: make sure to update the copies in the different encoders if you change + * this table */ +const int avpriv_mpeg4audio_sample_rates[16] = { + 96000, 88200, 64000, 48000, 44100, 32000, + 24000, 22050, 16000, 12000, 11025, 8000, 7350 +}; + +const uint8_t ff_mpeg4audio_channels[8] = { + 0, 1, 2, 3, 4, 5, 6, 8 +}; + +static inline int get_object_type(GetBitContext *gb) +{ + int object_type = get_bits(gb, 5); + if (object_type == AOT_ESCAPE) + object_type = 32 + get_bits(gb, 6); + return object_type; +} + +static inline int get_sample_rate(GetBitContext *gb, int *index) +{ + *index = get_bits(gb, 4); + return *index == 0x0f ? get_bits(gb, 24) : + avpriv_mpeg4audio_sample_rates[*index]; +} + +int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, + int bit_size, int sync_extension) +{ + GetBitContext gb; + int specific_config_bitindex; + + if (bit_size <= 0 || init_get_bits(&gb, buf, bit_size) < 0) + return AVERROR_INVALIDDATA; + c->object_type = get_object_type(&gb); + c->sample_rate = get_sample_rate(&gb, &c->sampling_index); + c->chan_config = get_bits(&gb, 4); + if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels)) + c->channels = ff_mpeg4audio_channels[c->chan_config]; + c->sbr = -1; + c->ps = -1; + if (c->object_type == AOT_SBR || (c->object_type == AOT_PS && + // check for W6132 Annex YYYY draft MP3onMP4 + !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) { + if (c->object_type == AOT_PS) + c->ps = 1; + c->ext_object_type = AOT_SBR; + c->sbr = 1; + c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); + c->object_type = get_object_type(&gb); + if (c->object_type == AOT_ER_BSAC) + c->ext_chan_config = get_bits(&gb, 4); + } else { + c->ext_object_type = AOT_NULL; + c->ext_sample_rate = 0; + } + specific_config_bitindex = get_bits_count(&gb); + + if (c->object_type == AOT_ALS) { + skip_bits(&gb, 5); + if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S')) + skip_bits_long(&gb, 24); + + specific_config_bitindex = get_bits_count(&gb); + + if (parse_config_ALS(&gb, c)) + return -1; + } + + if (c->ext_object_type != AOT_SBR && sync_extension) { + while (get_bits_left(&gb) > 15) { + if (show_bits(&gb, 11) == 0x2b7) { // sync extension + get_bits(&gb, 11); + c->ext_object_type = get_object_type(&gb); + if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) { + c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); + if (c->ext_sample_rate == c->sample_rate) + c->sbr = -1; + } + if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548) + c->ps = get_bits1(&gb); + break; + } else + get_bits1(&gb); // skip 1 bit + } + } + + //PS requires SBR + if (!c->sbr) + c->ps = 0; + //Limit implicit PS to the HE-AACv2 Profile + if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01) + c->ps = 0; + + return specific_config_bitindex; +} + +static av_always_inline unsigned int copy_bits(PutBitContext *pb, + GetBitContext *gb, + int bits) +{ + unsigned int el = get_bits(gb, bits); + put_bits(pb, bits, el); + return el; +} + +int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb) +{ + int five_bit_ch, four_bit_ch, comment_size, bits; + int offset = put_bits_count(pb); + + copy_bits(pb, gb, 10); //Tag, Object Type, Frequency + five_bit_ch = copy_bits(pb, gb, 4); //Front + five_bit_ch += copy_bits(pb, gb, 4); //Side + five_bit_ch += copy_bits(pb, gb, 4); //Back + four_bit_ch = copy_bits(pb, gb, 2); //LFE + four_bit_ch += copy_bits(pb, gb, 3); //Data + five_bit_ch += copy_bits(pb, gb, 4); //Coupling + if (copy_bits(pb, gb, 1)) //Mono Mixdown + copy_bits(pb, gb, 4); + if (copy_bits(pb, gb, 1)) //Stereo Mixdown + copy_bits(pb, gb, 4); + if (copy_bits(pb, gb, 1)) //Matrix Mixdown + copy_bits(pb, gb, 3); + for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16) + copy_bits(pb, gb, 16); + if (bits) + copy_bits(pb, gb, bits); + avpriv_align_put_bits(pb); + align_get_bits(gb); + comment_size = copy_bits(pb, gb, 8); + for (; comment_size > 0; comment_size--) + copy_bits(pb, gb, 8); + + return put_bits_count(pb) - offset; +} |