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  1. /*
  2.  * Real Audio 1.0 (14.4K)
  3.  *
  4.  * Copyright (c) 2008 Vitor Sessak
  5.  * Copyright (c) 2003 Nick Kurshev
  6.  *     Based on public domain decoder at http://www.honeypot.net/audio
  7.  *
  8.  * This file is part of FFmpeg.
  9.  *
  10.  * FFmpeg is free software; you can redistribute it and/or
  11.  * modify it under the terms of the GNU Lesser General Public
  12.  * License as published by the Free Software Foundation; either
  13.  * version 2.1 of the License, or (at your option) any later version.
  14.  *
  15.  * FFmpeg is distributed in the hope that it will be useful,
  16.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18.  * Lesser General Public License for more details.
  19.  *
  20.  * You should have received a copy of the GNU Lesser General Public
  21.  * License along with FFmpeg; if not, write to the Free Software
  22.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23.  */
  24.  
  25. #include "libavutil/channel_layout.h"
  26. #include "avcodec.h"
  27. #include "get_bits.h"
  28. #include "internal.h"
  29. #include "ra144.h"
  30.  
  31.  
  32. static av_cold int ra144_decode_init(AVCodecContext * avctx)
  33. {
  34.     RA144Context *ractx = avctx->priv_data;
  35.  
  36.     ractx->avctx = avctx;
  37.     ff_audiodsp_init(&ractx->adsp);
  38.  
  39.     ractx->lpc_coef[0] = ractx->lpc_tables[0];
  40.     ractx->lpc_coef[1] = ractx->lpc_tables[1];
  41.  
  42.     avctx->channels       = 1;
  43.     avctx->channel_layout = AV_CH_LAYOUT_MONO;
  44.     avctx->sample_fmt     = AV_SAMPLE_FMT_S16;
  45.  
  46.     return 0;
  47. }
  48.  
  49. static void do_output_subblock(RA144Context *ractx, const int16_t  *lpc_coefs,
  50.                                int gval, GetBitContext *gb)
  51. {
  52.     int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
  53.     int gain    = get_bits(gb, 8);
  54.     int cb1_idx = get_bits(gb, 7);
  55.     int cb2_idx = get_bits(gb, 7);
  56.  
  57.     ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval,
  58.                           gain);
  59. }
  60.  
  61. /** Uncompress one block (20 bytes -> 160*2 bytes). */
  62. static int ra144_decode_frame(AVCodecContext * avctx, void *data,
  63.                               int *got_frame_ptr, AVPacket *avpkt)
  64. {
  65.     AVFrame *frame     = data;
  66.     const uint8_t *buf = avpkt->data;
  67.     int buf_size = avpkt->size;
  68.     static const uint8_t sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
  69.     unsigned int refl_rms[NBLOCKS];           // RMS of the reflection coefficients
  70.     int16_t block_coefs[NBLOCKS][LPC_ORDER];  // LPC coefficients of each sub-block
  71.     unsigned int lpc_refl[LPC_ORDER];         // LPC reflection coefficients of the frame
  72.     int i, j;
  73.     int ret;
  74.     int16_t *samples;
  75.     unsigned int energy;
  76.  
  77.     RA144Context *ractx = avctx->priv_data;
  78.     GetBitContext gb;
  79.  
  80.     if (buf_size < FRAME_SIZE) {
  81.         av_log(avctx, AV_LOG_ERROR,
  82.                "Frame too small (%d bytes). Truncated file?\n", buf_size);
  83.         *got_frame_ptr = 0;
  84.         return AVERROR_INVALIDDATA;
  85.     }
  86.  
  87.     /* get output buffer */
  88.     frame->nb_samples = NBLOCKS * BLOCKSIZE;
  89.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
  90.         return ret;
  91.     samples = (int16_t *)frame->data[0];
  92.  
  93.     init_get_bits8(&gb, buf, FRAME_SIZE);
  94.  
  95.     for (i = 0; i < LPC_ORDER; i++)
  96.         lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])];
  97.  
  98.     ff_eval_coefs(ractx->lpc_coef[0], lpc_refl);
  99.     ractx->lpc_refl_rms[0] = ff_rms(lpc_refl);
  100.  
  101.     energy = ff_energy_tab[get_bits(&gb, 5)];
  102.  
  103.     refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy);
  104.     refl_rms[1] = ff_interp(ractx, block_coefs[1], 2,
  105.                             energy <= ractx->old_energy,
  106.                             ff_t_sqrt(energy*ractx->old_energy) >> 12);
  107.     refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy);
  108.     refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy);
  109.  
  110.     ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]);
  111.  
  112.     for (i=0; i < NBLOCKS; i++) {
  113.         do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb);
  114.  
  115.         for (j=0; j < BLOCKSIZE; j++)
  116.             *samples++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2);
  117.     }
  118.  
  119.     ractx->old_energy = energy;
  120.     ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0];
  121.  
  122.     FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]);
  123.  
  124.     *got_frame_ptr = 1;
  125.  
  126.     return FRAME_SIZE;
  127. }
  128.  
  129. AVCodec ff_ra_144_decoder = {
  130.     .name           = "real_144",
  131.     .long_name      = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
  132.     .type           = AVMEDIA_TYPE_AUDIO,
  133.     .id             = AV_CODEC_ID_RA_144,
  134.     .priv_data_size = sizeof(RA144Context),
  135.     .init           = ra144_decode_init,
  136.     .decode         = ra144_decode_frame,
  137.     .capabilities   = AV_CODEC_CAP_DR1,
  138. };
  139.