Libav 0.7.1
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00001 /* 00002 * Real Audio 1.0 (14.4K) 00003 * 00004 * Copyright (c) 2008 Vitor Sessak 00005 * Copyright (c) 2003 Nick Kurshev 00006 * Based on public domain decoder at http://www.honeypot.net/audio 00007 * 00008 * This file is part of Libav. 00009 * 00010 * Libav is free software; you can redistribute it and/or 00011 * modify it under the terms of the GNU Lesser General Public 00012 * License as published by the Free Software Foundation; either 00013 * version 2.1 of the License, or (at your option) any later version. 00014 * 00015 * Libav is distributed in the hope that it will be useful, 00016 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00017 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00018 * Lesser General Public License for more details. 00019 * 00020 * You should have received a copy of the GNU Lesser General Public 00021 * License along with Libav; if not, write to the Free Software 00022 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00023 */ 00024 00025 #include "libavutil/intmath.h" 00026 #include "avcodec.h" 00027 #include "get_bits.h" 00028 #include "ra144.h" 00029 00030 00031 static av_cold int ra144_decode_init(AVCodecContext * avctx) 00032 { 00033 RA144Context *ractx = avctx->priv_data; 00034 00035 ractx->avctx = avctx; 00036 00037 ractx->lpc_coef[0] = ractx->lpc_tables[0]; 00038 ractx->lpc_coef[1] = ractx->lpc_tables[1]; 00039 00040 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 00041 return 0; 00042 } 00043 00044 static void do_output_subblock(RA144Context *ractx, const uint16_t *lpc_coefs, 00045 int gval, GetBitContext *gb) 00046 { 00047 int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none 00048 int gain = get_bits(gb, 8); 00049 int cb1_idx = get_bits(gb, 7); 00050 int cb2_idx = get_bits(gb, 7); 00051 00052 ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval, 00053 gain); 00054 } 00055 00057 static int ra144_decode_frame(AVCodecContext * avctx, void *vdata, 00058 int *data_size, AVPacket *avpkt) 00059 { 00060 const uint8_t *buf = avpkt->data; 00061 int buf_size = avpkt->size; 00062 static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2}; 00063 unsigned int refl_rms[4]; // RMS of the reflection coefficients 00064 uint16_t block_coefs[4][10]; // LPC coefficients of each sub-block 00065 unsigned int lpc_refl[10]; // LPC reflection coefficients of the frame 00066 int i, j; 00067 int16_t *data = vdata; 00068 unsigned int energy; 00069 00070 RA144Context *ractx = avctx->priv_data; 00071 GetBitContext gb; 00072 00073 if (*data_size < 2*160) 00074 return -1; 00075 00076 if(buf_size < 20) { 00077 av_log(avctx, AV_LOG_ERROR, 00078 "Frame too small (%d bytes). Truncated file?\n", buf_size); 00079 *data_size = 0; 00080 return buf_size; 00081 } 00082 init_get_bits(&gb, buf, 20 * 8); 00083 00084 for (i=0; i<10; i++) 00085 lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])]; 00086 00087 ff_eval_coefs(ractx->lpc_coef[0], lpc_refl); 00088 ractx->lpc_refl_rms[0] = ff_rms(lpc_refl); 00089 00090 energy = ff_energy_tab[get_bits(&gb, 5)]; 00091 00092 refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy); 00093 refl_rms[1] = ff_interp(ractx, block_coefs[1], 2, 00094 energy <= ractx->old_energy, 00095 ff_t_sqrt(energy*ractx->old_energy) >> 12); 00096 refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy); 00097 refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy); 00098 00099 ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]); 00100 00101 for (i=0; i < 4; i++) { 00102 do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb); 00103 00104 for (j=0; j < BLOCKSIZE; j++) 00105 *data++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2); 00106 } 00107 00108 ractx->old_energy = energy; 00109 ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0]; 00110 00111 FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]); 00112 00113 *data_size = 2*160; 00114 return 20; 00115 } 00116 00117 AVCodec ff_ra_144_decoder = 00118 { 00119 "real_144", 00120 AVMEDIA_TYPE_AUDIO, 00121 CODEC_ID_RA_144, 00122 sizeof(RA144Context), 00123 ra144_decode_init, 00124 NULL, 00125 NULL, 00126 ra144_decode_frame, 00127 .long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"), 00128 };