/*
  * Real Audio 1.0 (14.4K)
  *
  * Copyright (c) 2008 Vitor Sessak
  * Copyright (c) 2003 Nick Kurshev
  *     Based on public domain decoder at http://www.honeypot.net/audio
  *
  * 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
  */
 
 #include "libavutil/intmath.h"
 #include "avcodec.h"
 #include "get_bits.h"
 #include "ra144.h"
 
 
 static av_cold int ra144_decode_init(AVCodecContext * avctx)
 {
     RA144Context *ractx = avctx->priv_data;
 
     ractx->avctx = avctx;
 
     ractx->lpc_coef[0] = ractx->lpc_tables[0];
     ractx->lpc_coef[1] = ractx->lpc_tables[1];
 

     avctx->sample_fmt = AV_SAMPLE_FMT_S16;

 
     avcodec_get_frame_defaults(&ractx->frame);
     avctx->coded_frame = &ractx->frame;
 

     return 0;
 }
 
 static void do_output_subblock(RA144Context *ractx, const uint16_t  *lpc_coefs,
                                int gval, GetBitContext *gb)
 {
     int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
     int gain    = get_bits(gb, 8);
     int cb1_idx = get_bits(gb, 7);
     int cb2_idx = get_bits(gb, 7);
 

     ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval,
                           gain);

 }
 
 /** Uncompress one block (20 bytes -> 160*2 bytes). */

 static int ra144_decode_frame(AVCodecContext * avctx, void *data,
                               int *got_frame_ptr, AVPacket *avpkt)

 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     static const uint8_t sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
     unsigned int refl_rms[NBLOCKS];           // RMS of the reflection coefficients
     uint16_t block_coefs[NBLOCKS][LPC_ORDER]; // LPC coefficients of each sub-block
     unsigned int lpc_refl[LPC_ORDER];         // LPC reflection coefficients of the frame

     int i, j;

     int ret;
     int16_t *samples;

     unsigned int energy;
 
     RA144Context *ractx = avctx->priv_data;
     GetBitContext gb;
 

     /* get output buffer */
     ractx->frame.nb_samples = NBLOCKS * BLOCKSIZE;
     if ((ret = avctx->get_buffer(avctx, &ractx->frame)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return ret;

     }

     samples = (int16_t *)ractx->frame.data[0];

     if(buf_size < FRAMESIZE) {

         av_log(avctx, AV_LOG_ERROR,
                "Frame too small (%d bytes). Truncated file?\n", buf_size);

         *got_frame_ptr = 0;

         return buf_size;
     }

     init_get_bits(&gb, buf, FRAMESIZE * 8);

     for (i = 0; i < LPC_ORDER; i++)

         lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])];

     ff_eval_coefs(ractx->lpc_coef[0], lpc_refl);
     ractx->lpc_refl_rms[0] = ff_rms(lpc_refl);

     energy = ff_energy_tab[get_bits(&gb, 5)];

     refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy);
     refl_rms[1] = ff_interp(ractx, block_coefs[1], 2,
                             energy <= ractx->old_energy,
                             ff_t_sqrt(energy*ractx->old_energy) >> 12);
     refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy);
     refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy);

     ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]);

     for (i=0; i < NBLOCKS; i++) {

         do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb);
 
         for (j=0; j < BLOCKSIZE; j++)

             *samples++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2);

     }
 
     ractx->old_energy = energy;
     ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0];
 
     FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]);
 

     *got_frame_ptr   = 1;
     *(AVFrame *)data = ractx->frame;
 

     return FRAMESIZE;

 }
 

 AVCodec ff_ra_144_decoder = {
     .name           = "real_144",
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = CODEC_ID_RA_144,
     .priv_data_size = sizeof(RA144Context),
     .init           = ra144_decode_init,
     .decode         = ra144_decode_frame,

     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),

 };