| /* | |
| * AC-3 parser internal code | |
| * | |
| * 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 | |
| */ | |
| /** | |
| * @struct AC3HeaderInfo | |
| * Coded AC-3 header values up to the lfeon element, plus derived values. | |
| */ | |
| typedef struct AC3HeaderInfo { | |
| /** @name Coded elements | |
| * @{ | |
| */ | |
| uint16_t sync_word; | |
| uint16_t crc1; | |
| uint8_t sr_code; | |
| uint8_t bitstream_id; | |
| uint8_t bitstream_mode; | |
| uint8_t channel_mode; | |
| uint8_t lfe_on; | |
| uint8_t frame_type; | |
| int substreamid; ///< substream identification | |
| int center_mix_level; ///< Center mix level index | |
| int surround_mix_level; ///< Surround mix level index | |
| uint16_t channel_map; | |
| int num_blocks; ///< number of audio blocks | |
| int dolby_surround_mode; | |
| /** @} */ | |
| /** @name Derived values | |
| * @{ | |
| */ | |
| uint8_t sr_shift; | |
| uint16_t sample_rate; | |
| uint32_t bit_rate; | |
| uint8_t channels; | |
| uint16_t frame_size; | |
| uint64_t channel_layout; | |
| int8_t ac3_bit_rate_code; | |
| /** @} */ | |
| } AC3HeaderInfo; | |
| /** | |
| * Parse AC-3 frame header. | |
| * Parse the header up to the lfeon element, which is the first 52 or 54 bits | |
| * depending on the audio coding mode. | |
| * @param[in] gbc BitContext containing the first 54 bits of the frame. | |
| * @param[out] hdr Pointer to struct where header info is written. | |
| * @return Returns 0 on success, -1 if there is a sync word mismatch, | |
| * -2 if the bsid (version) element is invalid, -3 if the fscod (sample rate) | |
| * element is invalid, or -4 if the frmsizecod (bit rate) element is invalid. | |
| */ | |
| int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr); | |
| int avpriv_ac3_parse_header(AC3HeaderInfo **hdr, const uint8_t *buf, | |
| size_t size); | |
| int ff_ac3_find_syncword(const uint8_t *buf, int buf_size); | |