/*
  * SMPTE 302M decoder
  * Copyright (c) 2008 Laurent Aimar <fenrir@videolan.org>
  * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
  *

  * 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/intreadwrite.h"

 #include "libavutil/opt.h"

 #include "libavutil/log.h"

 #include "avcodec.h"

 #include "internal.h"

 #include "mathops.h"

 
 #define AES3_HEADER_LEN 4
 

 typedef struct S302Context {
     AVClass *class;
     int non_pcm_mode;
 } S302Context;
 

 static int s302m_parse_frame_header(AVCodecContext *avctx, const uint8_t *buf,
                                     int buf_size)
 {
     uint32_t h;

     int frame_size, channels, bits;

 
     if (buf_size <= AES3_HEADER_LEN) {
         av_log(avctx, AV_LOG_ERROR, "frame is too short\n");
         return AVERROR_INVALIDDATA;
     }
 
     /*
      * AES3 header :
      * size:            16
      * number channels   2
      * channel_id        8
      * bits per samples  2
      * alignments        4
      */
 
     h = AV_RB32(buf);
     frame_size =  (h >> 16) & 0xffff;
     channels   = ((h >> 14) & 0x0003) * 2 +  2;
     bits       = ((h >>  4) & 0x0003) * 4 + 16;
 
     if (AES3_HEADER_LEN + frame_size != buf_size || bits > 24) {
         av_log(avctx, AV_LOG_ERROR, "frame has invalid header\n");
         return AVERROR_INVALIDDATA;
     }
 
     /* Set output properties */

     avctx->bits_per_raw_sample = bits;

     if (bits > 16)

         avctx->sample_fmt = AV_SAMPLE_FMT_S32;

     else

         avctx->sample_fmt = AV_SAMPLE_FMT_S16;

 
     avctx->channels    = channels;

     switch(channels) {
         case 2:
             avctx->channel_layout = AV_CH_LAYOUT_STEREO;
             break;
         case 4:
             avctx->channel_layout = AV_CH_LAYOUT_QUAD;
             break;

         case 6:
             avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK;
             break;

         case 8:
             avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX;
     }

 
     return frame_size;
 }
 
 static int s302m_decode_frame(AVCodecContext *avctx, void *data,

                               int *got_frame_ptr, AVPacket *avpkt)

 {

     S302Context *s = avctx->priv_data;

     AVFrame *frame     = data;

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

     int block_size, ret;

     int i;
     int non_pcm_data_type = -1;

 
     int frame_size = s302m_parse_frame_header(avctx, buf, buf_size);
     if (frame_size < 0)
         return frame_size;
 
     buf_size -= AES3_HEADER_LEN;
     buf      += AES3_HEADER_LEN;
 

     /* get output buffer */

     block_size = (avctx->bits_per_raw_sample + 4) / 4;

     frame->nb_samples = 2 * (buf_size / block_size) / avctx->channels;

     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

         return ret;
 

     avctx->bit_rate = 48000 * avctx->channels * (avctx->bits_per_raw_sample + 4) +
                       32 * 48000 / frame->nb_samples;

     buf_size = (frame->nb_samples * avctx->channels / 2) * block_size;

     if (avctx->bits_per_raw_sample == 24) {

         uint32_t *o = (uint32_t *)frame->data[0];

         for (; buf_size > 6; buf_size -= 7) {

             *o++ = ((unsigned)ff_reverse[buf[2]]        << 24) |

                    (ff_reverse[buf[1]]        << 16) |
                    (ff_reverse[buf[0]]        <<  8);

             *o++ = ((unsigned)ff_reverse[buf[6] & 0xf0] << 28) |

                    (ff_reverse[buf[5]]        << 20) |
                    (ff_reverse[buf[4]]        << 12) |
                    (ff_reverse[buf[3] & 0x0f] <<  4);

             buf += 7;
         }

         o = (uint32_t *)frame->data[0];
         if (avctx->channels == 2)
             for (i=0; i<frame->nb_samples * 2 - 6; i+=2) {
                 if (o[i] || o[i+1] || o[i+2] || o[i+3])
                     break;
                 if (o[i+4] == 0x96F87200U && o[i+5] == 0xA54E1F00) {
                     non_pcm_data_type = (o[i+6] >> 16) & 0x1F;
                     break;
                 }
             }

     } else if (avctx->bits_per_raw_sample == 20) {

         uint32_t *o = (uint32_t *)frame->data[0];

         for (; buf_size > 5; buf_size -= 6) {

             *o++ = ((unsigned)ff_reverse[buf[2] & 0xf0] << 28) |

                    (ff_reverse[buf[1]]        << 20) |
                    (ff_reverse[buf[0]]        << 12);

             *o++ = ((unsigned)ff_reverse[buf[5] & 0xf0] << 28) |

                    (ff_reverse[buf[4]]        << 20) |
                    (ff_reverse[buf[3]]        << 12);

             buf += 6;
         }

         o = (uint32_t *)frame->data[0];
         if (avctx->channels == 2)
             for (i=0; i<frame->nb_samples * 2 - 6; i+=2) {
                 if (o[i] || o[i+1] || o[i+2] || o[i+3])
                     break;
                 if (o[i+4] == 0x6F872000U && o[i+5] == 0x54E1F000) {
                     non_pcm_data_type = (o[i+6] >> 16) & 0x1F;
                     break;
                 }
             }

     } else {

         uint16_t *o = (uint16_t *)frame->data[0];

         for (; buf_size > 4; buf_size -= 5) {

             *o++ = (ff_reverse[buf[1]]        <<  8) |
                     ff_reverse[buf[0]];
             *o++ = (ff_reverse[buf[4] & 0xf0] << 12) |
                    (ff_reverse[buf[3]]        <<  4) |
                    (ff_reverse[buf[2]]        >>  4);

             buf += 5;
         }

         o = (uint16_t *)frame->data[0];
         if (avctx->channels == 2)
             for (i=0; i<frame->nb_samples * 2 - 6; i+=2) {
                 if (o[i] || o[i+1] || o[i+2] || o[i+3])
                     break;
                 if (o[i+4] == 0xF872U && o[i+5] == 0x4E1F) {
                     non_pcm_data_type = (o[i+6] & 0x1F);
                     break;
                 }
             }
     }
 
     if (non_pcm_data_type != -1) {
         if (s->non_pcm_mode == 3) {
             av_log(avctx, AV_LOG_ERROR,
                    "S302 non PCM mode with data type %d not supported\n",
                    non_pcm_data_type);
             return AVERROR_PATCHWELCOME;
         }
         if (s->non_pcm_mode & 1) {
             return avpkt->size;
         }

     }
 

     avctx->sample_rate = 48000;
 

     *got_frame_ptr = 1;

 
     return avpkt->size;
 }
 

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_DECODING_PARAM
 static const AVOption s302m_options[] = {

     {"non_pcm_mode", "Chooses what to do with NON-PCM", offsetof(S302Context, non_pcm_mode), AV_OPT_TYPE_INT, {.i64 = 3}, 0, 3, FLAGS, "non_pcm_mode"},
     {"copy"        , "Pass NON-PCM through unchanged"     , 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 3, FLAGS, "non_pcm_mode"},
     {"drop"        , "Drop NON-PCM"                       , 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 3, FLAGS, "non_pcm_mode"},
     {"decode_copy" , "Decode if possible else passthrough", 0, AV_OPT_TYPE_CONST, {.i64 = 2}, 0, 3, FLAGS, "non_pcm_mode"},
     {"decode_drop" , "Decode if possible else drop"       , 0, AV_OPT_TYPE_CONST, {.i64 = 3}, 0, 3, FLAGS, "non_pcm_mode"},

     {NULL}
 };
 
 static const AVClass s302m_class = {
     "SMPTE 302M Decoder",
     av_default_item_name,
     s302m_options,
     LIBAVUTIL_VERSION_INT,
 };
 

 AVCodec ff_s302m_decoder = {
     .name           = "s302m",

     .long_name      = NULL_IF_CONFIG_SMALL("SMPTE 302M"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_S302M,

     .priv_data_size = sizeof(S302Context),

     .decode         = s302m_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

     .priv_class     = &s302m_class,

 };