text: /*
   * Forward Uncompressed
   *
   * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
   *
   * This file is part of Libav.
   *
   * Libav 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.
   *
   * Libav 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 Libav; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "avcodec.h"
  #include "bytestream.h"
  #include "libavutil/intreadwrite.h"
  
  static av_cold int decode_init(AVCodecContext *avctx)
  {
      if (avctx->width & 1) {
          av_log(avctx, AV_LOG_ERROR, "FRWU needs even width\n");
          return -1;
      }
      avctx->pix_fmt = PIX_FMT_UYVY422;
  
      avctx->coded_frame = avcodec_alloc_frame();
  
      return 0;
  }
  
  static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
                          AVPacket *avpkt)
  {
      int field;
      AVFrame *pic = avctx->coded_frame;
      const uint8_t *buf = avpkt->data;
      const uint8_t *buf_end = buf + avpkt->size;
  
      if (pic->data[0])
          avctx->release_buffer(avctx, pic);
  
      if (avpkt->size < avctx->width * 2 * avctx->height + 4 + 2*8) {
          av_log(avctx, AV_LOG_ERROR, "Packet is too small.\n");
          return -1;
      }
      if (bytestream_get_le32(&buf) != AV_RL32("FRW1")) {
          av_log(avctx, AV_LOG_ERROR, "incorrect marker\n");
          return -1;
      }
  
      pic->reference = 0;
      if (avctx->get_buffer(avctx, pic) < 0)
          return -1;
  
      pic->pict_type = AV_PICTURE_TYPE_I;
      pic->key_frame = 1;
      pic->interlaced_frame = 1;
      pic->top_field_first = 1;
  
      for (field = 0; field < 2; field++) {
          int i;
          int field_h = (avctx->height + !field) >> 1;
          int field_size, min_field_size = avctx->width * 2 * field_h;
          uint8_t *dst = pic->data[0];
          if (buf_end - buf < 8)
              return -1;
          buf += 4; // flags? 0x80 == bottom field maybe?
          field_size = bytestream_get_le32(&buf);
          if (field_size < min_field_size) {
              av_log(avctx, AV_LOG_ERROR, "Field size %i is too small (required %i)\n", field_size, min_field_size);
              return -1;
          }
          if (buf_end - buf < field_size) {
              av_log(avctx, AV_LOG_ERROR, "Packet is too small, need %i, have %i\n", field_size, (int)(buf_end - buf));
              return -1;
          }
          if (field)
              dst += pic->linesize[0];
          for (i = 0; i < field_h; i++) {
              memcpy(dst, buf, avctx->width * 2);
              buf += avctx->width * 2;
              dst += pic->linesize[0] << 1;
          }
          buf += field_size - min_field_size;
      }
  
      *data_size = sizeof(AVFrame);
      *(AVFrame*)data = *pic;
  
      return avpkt->size;
  }
  
  static av_cold int decode_close(AVCodecContext *avctx)
  {
      AVFrame *pic = avctx->coded_frame;
      if (pic->data[0])
          avctx->release_buffer(avctx, pic);
      av_freep(&avctx->coded_frame);
  
      return 0;
  }
  
  AVCodec ff_frwu_decoder = {
      .name           = "FRWU",
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = CODEC_ID_FRWU,
      .init           = decode_init,
      .close          = decode_close,
      .decode         = decode_frame,
      .capabilities   = CODEC_CAP_DR1,
      .long_name = NULL_IF_CONFIG_SMALL("Forward Uncompressed"),
  };
  