/*
  * ADX ADPCM codecs
  * Copyright (c) 2001,2003 BERO
  *
  * 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 "avcodec.h"
 #include "adx.h"

 #include "bytestream.h"

 #include "internal.h"

 #include "put_bits.h"

 
 /**

  * @file

  * SEGA CRI adx codecs.
  *
  * Reference documents:
  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
  */
 

 static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav,

                        ADXChannelState *prev, int channels)

 {

     PutBitContext pb;

     int scale;

     int i, j;

     int s0, s1, s2, d;
     int max = 0;
     int min = 0;

 
     s1 = prev->s1;
     s2 = prev->s2;

     for (i = 0, j = 0; j < 32; i += channels, j++) {

         s0 = wav[i];

         d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS;

         if (max < d)
             max = d;
         if (min > d)
             min = d;

         s2 = s1;
         s1 = s0;
     }
 

     if (max == 0 && min == 0) {

         prev->s1 = s1;
         prev->s2 = s2;

         memset(adx, 0, BLOCK_SIZE);

         return;
     }
 

     if (max / 7 > -min / 8)
         scale = max / 7;
     else
         scale = -min / 8;

     if (scale == 0)
         scale = 1;

 
     AV_WB16(adx, scale);
 

     init_put_bits(&pb, adx + 2, 16);

 
     s1 = prev->s1;
     s2 = prev->s2;
     for (i = 0, j = 0; j < 32; i += channels, j++) {
         d = ((wav[i] << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS;
 

         d = av_clip_intp2(ROUNDED_DIV(d, scale), 3);

 
         put_sbits(&pb, 4, d);
 
         s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
         s2 = s1;
         s1 = s0;
     }
     prev->s1 = s1;
     prev->s2 = s2;
 

     flush_put_bits(&pb);

 }
 

 #define HEADER_SIZE 36
 

 static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize)

 {

     ADXContext *c = avctx->priv_data;
 

     bytestream_put_be16(&buf, 0x8000);              /* header signature */
     bytestream_put_be16(&buf, HEADER_SIZE - 4);     /* copyright offset */
     bytestream_put_byte(&buf, 3);                   /* encoding */
     bytestream_put_byte(&buf, BLOCK_SIZE);          /* block size */
     bytestream_put_byte(&buf, 4);                   /* sample size */
     bytestream_put_byte(&buf, avctx->channels);     /* channels */
     bytestream_put_be32(&buf, avctx->sample_rate);  /* sample rate */
     bytestream_put_be32(&buf, 0);                   /* total sample count */
     bytestream_put_be16(&buf, c->cutoff);           /* cutoff frequency */
     bytestream_put_byte(&buf, 3);                   /* version */
     bytestream_put_byte(&buf, 0);                   /* flags */
     bytestream_put_be32(&buf, 0);                   /* unknown */
     bytestream_put_be32(&buf, 0);                   /* loop enabled */
     bytestream_put_be16(&buf, 0);                   /* padding */
     bytestream_put_buffer(&buf, "(c)CRI", 6);       /* copyright signature */
 
     return HEADER_SIZE;

 }
 

 static av_cold int adx_encode_init(AVCodecContext *avctx)

 {

     ADXContext *c = avctx->priv_data;
 

     if (avctx->channels > 2) {
         av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");
         return AVERROR(EINVAL);
     }

     avctx->frame_size = BLOCK_SAMPLES;

     /* the cutoff can be adjusted, but this seems to work pretty well */
     c->cutoff = 500;
     ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff);
 

     return 0;
 }
 

 static int adx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                             const AVFrame *frame, int *got_packet_ptr)

 {

     ADXContext *c          = avctx->priv_data;

     const int16_t *samples = (const int16_t *)frame->data[0];
     uint8_t *dst;
     int ch, out_size, ret;
 
     out_size = BLOCK_SIZE * avctx->channels + !c->header_parsed * HEADER_SIZE;

     if ((ret = ff_alloc_packet2(avctx, avpkt, out_size, 0)) < 0)

         return ret;
     dst = avpkt->data;

 
     if (!c->header_parsed) {

         int hdrsize;

         if ((hdrsize = adx_encode_header(avctx, dst, avpkt->size)) < 0) {

             av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n");
             return AVERROR(EINVAL);
         }
         dst      += hdrsize;

         c->header_parsed = 1;
     }
 

     for (ch = 0; ch < avctx->channels; ch++) {
         adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels);

         dst += BLOCK_SIZE;

     }

 
     *got_packet_ptr = 1;
     return 0;

 }
 

 AVCodec ff_adpcm_adx_encoder = {

     .name           = "adpcm_adx",

     .long_name      = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_ADPCM_ADX,

     .priv_data_size = sizeof(ADXContext),
     .init           = adx_encode_init,

     .encode2        = adx_encode_frame,

     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
                                                       AV_SAMPLE_FMT_NONE },

 };