/*
  * Aura 2 decoder
  *
  * 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
  */
 
 /**

  * @file

  * Aura 2 decoder
  */
 
 #include "avcodec.h"

 #include "internal.h"

 #include "libavutil/internal.h"

 
 static av_cold int aura_decode_init(AVCodecContext *avctx)
 {
     /* width needs to be divisible by 4 for this codec to work */
     if (avctx->width & 0x3)

         return AVERROR(EINVAL);

     avctx->pix_fmt = AV_PIX_FMT_YUV422P;

 
     return 0;
 }
 
 static int aura_decode_frame(AVCodecContext *avctx,

                              void *data, int *got_frame,

                              AVPacket *pkt)
 {

     AVFrame *frame = data;

     uint8_t *Y, *U, *V;
     uint8_t val;

     int x, y, ret;

     const uint8_t *buf = pkt->data;
 
     /* prediction error tables (make it clear that they are signed values) */
     const int8_t *delta_table = (const int8_t*)buf + 16;
 
     if (pkt->size != 48 + avctx->height * avctx->width) {
         av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
                pkt->size, 48 + avctx->height * avctx->width);

         return AVERROR_INVALIDDATA;

     }
 
     /* pixel data starts 48 bytes in, after 3x16-byte tables */
     buf += 48;
 

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

         return ret;

     Y = frame->data[0];
     U = frame->data[1];
     V = frame->data[2];

 
     /* iterate through each line in the height */
     for (y = 0; y < avctx->height; y++) {
         /* reset predictors */

         val  = *buf++;

         U[0] = val & 0xF0;
         Y[0] = val << 4;

         val  = *buf++;

         V[0] = val & 0xF0;
         Y[1] = Y[0] + delta_table[val & 0xF];

         Y   += 2; U++; V++;

 
         /* iterate through the remaining pixel groups (4 pixels/group) */
         for (x = 1; x < (avctx->width >> 1); x++) {

             val  = *buf++;

             U[0] = U[-1] + delta_table[val >> 4];
             Y[0] = Y[-1] + delta_table[val & 0xF];

             val  = *buf++;

             V[0] = V[-1] + delta_table[val >> 4];
             Y[1] = Y[ 0] + delta_table[val & 0xF];

             Y   += 2; U++; V++;

         }

         Y += frame->linesize[0] -  avctx->width;
         U += frame->linesize[1] - (avctx->width >> 1);
         V += frame->linesize[2] - (avctx->width >> 1);

     }
 

     *got_frame = 1;

 
     return pkt->size;
 }
 

 AVCodec ff_aura2_decoder = {

     .name           = "aura2",

     .long_name      = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_AURA2,

     .init           = aura_decode_init,
     .decode         = aura_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,

 };