| /* |
| * 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 AVERROR_INVALIDDATA; |
| |
| if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0')) |
| return AVERROR_INVALIDDATA; |
| |
| // override AudioSpecificConfig channel configuration and sample rate |
| // which are buggy in old ALS conformance files |
| c->sample_rate = get_bits_long(gb, 32); |
| |
| if (c->sample_rate <= 0) { |
| av_log(NULL, AV_LOG_ERROR, "Invalid sample rate %d\n", c->sample_rate); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| // 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[14] = { |
| 0, |
| 1, // mono (1/0) |
| 2, // stereo (2/0) |
| 3, // 3/0 |
| 4, // 3/1 |
| 5, // 3/2 |
| 6, // 3/2.1 |
| 8, // 5/2.1 |
| 0, |
| 0, |
| 0, |
| 7, // 3/3.1 |
| 8, // 3/2/2.1 |
| 24 // 3/3/3 - 5/2/3 - 3/0/0.2 |
| }; |
| |
| 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 ff_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb, |
| int sync_extension, void *logctx) |
| { |
| int specific_config_bitindex, ret; |
| int start_bit_index = get_bits_count(gb); |
| 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]; |
| else { |
| av_log(logctx, AV_LOG_ERROR, "Invalid chan_config %d\n", c->chan_config); |
| return AVERROR_INVALIDDATA; |
| } |
| 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(gb, 24) != MKBETAG('\0','A','L','S')) |
| skip_bits(gb, 24); |
| |
| specific_config_bitindex = get_bits_count(gb); |
| |
| ret = parse_config_ALS(gb, c); |
| if (ret < 0) |
| return ret; |
| } |
| |
| 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 - start_bit_index; |
| } |
| |
| #if LIBAVCODEC_VERSION_MAJOR < 59 |
| int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, |
| int bit_size, int sync_extension) |
| { |
| GetBitContext gb; |
| int ret; |
| |
| if (bit_size <= 0) |
| return AVERROR_INVALIDDATA; |
| |
| ret = init_get_bits(&gb, buf, bit_size); |
| if (ret < 0) |
| return ret; |
| |
| return ff_mpeg4audio_get_config_gb(c, &gb, sync_extension, NULL); |
| } |
| #endif |
| |
| int avpriv_mpeg4audio_get_config2(MPEG4AudioConfig *c, const uint8_t *buf, |
| int size, int sync_extension, void *logctx) |
| { |
| GetBitContext gb; |
| int ret; |
| |
| if (size <= 0) |
| return AVERROR_INVALIDDATA; |
| |
| ret = init_get_bits8(&gb, buf, size); |
| if (ret < 0) |
| return ret; |
| |
| return ff_mpeg4audio_get_config_gb(c, &gb, sync_extension, logctx); |
| } |
