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125 lines
4.1 KiB
125 lines
4.1 KiB
/* |
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* Real Audio 1.0 (14.4K) |
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* |
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* Copyright (c) 2008 Vitor Sessak |
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* Copyright (c) 2003 Nick Kurshev |
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* Based on public domain decoder at http://www.honeypot.net/audio |
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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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#include "libavutil/intmath.h" |
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#include "avcodec.h" |
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#include "get_bits.h" |
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#include "ra144.h" |
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static av_cold int ra144_decode_init(AVCodecContext * avctx) |
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{ |
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RA144Context *ractx = avctx->priv_data; |
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ractx->avctx = avctx; |
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ractx->lpc_coef[0] = ractx->lpc_tables[0]; |
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ractx->lpc_coef[1] = ractx->lpc_tables[1]; |
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avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
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return 0; |
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} |
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static void do_output_subblock(RA144Context *ractx, const uint16_t *lpc_coefs, |
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int gval, GetBitContext *gb) |
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{ |
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int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none |
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int gain = get_bits(gb, 8); |
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int cb1_idx = get_bits(gb, 7); |
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int cb2_idx = get_bits(gb, 7); |
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ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval, |
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gain); |
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} |
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/** Uncompress one block (20 bytes -> 160*2 bytes). */ |
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static int ra144_decode_frame(AVCodecContext * avctx, void *vdata, |
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int *data_size, AVPacket *avpkt) |
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{ |
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const uint8_t *buf = avpkt->data; |
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int buf_size = avpkt->size; |
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static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2}; |
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unsigned int refl_rms[4]; // RMS of the reflection coefficients |
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uint16_t block_coefs[4][10]; // LPC coefficients of each sub-block |
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unsigned int lpc_refl[10]; // LPC reflection coefficients of the frame |
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int i, j; |
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int16_t *data = vdata; |
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unsigned int energy; |
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RA144Context *ractx = avctx->priv_data; |
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GetBitContext gb; |
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if (*data_size < 2*160) |
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return -1; |
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if(buf_size < 20) { |
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av_log(avctx, AV_LOG_ERROR, |
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"Frame too small (%d bytes). Truncated file?\n", buf_size); |
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*data_size = 0; |
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return buf_size; |
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} |
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init_get_bits(&gb, buf, 20 * 8); |
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for (i=0; i<10; i++) |
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lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])]; |
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ff_eval_coefs(ractx->lpc_coef[0], lpc_refl); |
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ractx->lpc_refl_rms[0] = ff_rms(lpc_refl); |
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energy = ff_energy_tab[get_bits(&gb, 5)]; |
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refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy); |
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refl_rms[1] = ff_interp(ractx, block_coefs[1], 2, |
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energy <= ractx->old_energy, |
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ff_t_sqrt(energy*ractx->old_energy) >> 12); |
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refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy); |
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refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy); |
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ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]); |
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for (i=0; i < 4; i++) { |
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do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb); |
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for (j=0; j < BLOCKSIZE; j++) |
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*data++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2); |
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} |
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ractx->old_energy = energy; |
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ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0]; |
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FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]); |
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*data_size = 2*160; |
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return 20; |
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} |
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AVCodec ff_ra_144_decoder = { |
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.name = "real_144", |
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.type = AVMEDIA_TYPE_AUDIO, |
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.id = CODEC_ID_RA_144, |
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.priv_data_size = sizeof(RA144Context), |
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.init = ra144_decode_init, |
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.decode = ra144_decode_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"), |
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};
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