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99 lines
2.9 KiB
99 lines
2.9 KiB
/* |
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* copyright (c) 2001 Fabrice Bellard |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file mpegaudio.h |
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* mpeg audio declarations for both encoder and decoder. |
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*/ |
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/* max frame size, in samples */ |
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#define MPA_FRAME_SIZE 1152 |
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/* max compressed frame size */ |
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#define MPA_MAX_CODED_FRAME_SIZE 1792 |
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#define MPA_MAX_CHANNELS 2 |
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#define SBLIMIT 32 /* number of subbands */ |
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#define MPA_STEREO 0 |
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#define MPA_JSTEREO 1 |
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#define MPA_DUAL 2 |
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#define MPA_MONO 3 |
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/* header + layer + bitrate + freq + lsf/mpeg25 */ |
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#define SAME_HEADER_MASK \ |
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(0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19)) |
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#define MP3_MASK 0xFFFE0CCF |
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/* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg |
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audio decoder */ |
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#ifdef USE_HIGHPRECISION |
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#define FRAC_BITS 23 /* fractional bits for sb_samples and dct */ |
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#define WFRAC_BITS 16 /* fractional bits for window */ |
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#else |
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#define FRAC_BITS 15 /* fractional bits for sb_samples and dct */ |
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#define WFRAC_BITS 14 /* fractional bits for window */ |
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#endif |
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#if defined(USE_HIGHPRECISION) && defined(CONFIG_AUDIO_NONSHORT) |
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typedef int32_t OUT_INT; |
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#define OUT_MAX INT32_MAX |
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#define OUT_MIN INT32_MIN |
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#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31) |
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#else |
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typedef int16_t OUT_INT; |
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#define OUT_MAX INT16_MAX |
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#define OUT_MIN INT16_MIN |
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#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15) |
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#endif |
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#if FRAC_BITS <= 15 |
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typedef int16_t MPA_INT; |
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#else |
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typedef int32_t MPA_INT; |
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#endif |
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int l2_select_table(int bitrate, int nb_channels, int freq, int lsf); |
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int mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate); |
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void ff_mpa_synth_init(MPA_INT *window); |
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void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset, |
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MPA_INT *window, int *dither_state, |
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OUT_INT *samples, int incr, |
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int32_t sb_samples[SBLIMIT]); |
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/* fast header check for resync */ |
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static inline int ff_mpa_check_header(uint32_t header){ |
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/* header */ |
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if ((header & 0xffe00000) != 0xffe00000) |
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return -1; |
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/* layer check */ |
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if ((header & (3<<17)) == 0) |
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return -1; |
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/* bit rate */ |
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if ((header & (0xf<<12)) == 0xf<<12) |
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return -1; |
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/* frequency */ |
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if ((header & (3<<10)) == 3<<10) |
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return -1; |
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return 0; |
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}
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