text: /*
   * DXA demuxer
   * Copyright (c) 2007 Konstantin Shishkov
   *
   * 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 <inttypes.h>
  
  #include "libavutil/intreadwrite.h"
  #include "avformat.h"
  #include "internal.h"
  #include "riff.h"
  
  #define DXA_EXTRA_SIZE  9
  
  typedef struct DXAContext {
      int frames;
      int has_sound;
      int bpc;
      uint32_t bytes_left;
      int64_t wavpos, vidpos;
      int readvid;
  }DXAContext;
  
  static int dxa_probe(const AVProbeData *p)
  {
      int w, h;
      if (p->buf_size < 15)
          return 0;
      w = AV_RB16(p->buf + 11);
      h = AV_RB16(p->buf + 13);
      /* check file header */
      if (p->buf[0] == 'D' && p->buf[1] == 'E' &&
          p->buf[2] == 'X' && p->buf[3] == 'A' &&
          w && w <= 2048 && h && h <= 2048)
          return AVPROBE_SCORE_MAX;
      else
          return 0;
  }
  
  static int dxa_read_header(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
      DXAContext *c = s->priv_data;
      AVStream *st, *ast;
      uint32_t tag;
      int32_t fps;
      int w, h;
      int num, den;
      int flags;
      int ret;
  
      tag = avio_rl32(pb);
      if (tag != MKTAG('D', 'E', 'X', 'A'))
          return AVERROR_INVALIDDATA;
      flags = avio_r8(pb);
      c->frames = avio_rb16(pb);
      if(!c->frames){
          av_log(s, AV_LOG_ERROR, "File contains no frames ???\n");
          return AVERROR_INVALIDDATA;
      }
  
      fps = avio_rb32(pb);
      if(fps > 0){
          den = 1000;
          num = fps;
      }else if (fps < 0 && fps > INT_MIN){
          den = 100000;
          num = -fps;
      }else{
          den = 10;
          num = 1;
      }
      w = avio_rb16(pb);
      h = avio_rb16(pb);
      c->has_sound = 0;
  
      st = avformat_new_stream(s, NULL);
      if (!st)
          return AVERROR(ENOMEM);
  
      // Parse WAV data header
      if(avio_rl32(pb) == MKTAG('W', 'A', 'V', 'E')){
          uint32_t size, fsize;
          c->has_sound = 1;
          size = avio_rb32(pb);
          c->vidpos = avio_tell(pb) + size;
          avio_skip(pb, 16);
          fsize = avio_rl32(pb);
  
          ast = avformat_new_stream(s, NULL);
          if (!ast)
              return AVERROR(ENOMEM);
          ret = ff_get_wav_header(s, pb, ast->codecpar, fsize, 0);
          if (ret < 0)
              return ret;
          if (ast->codecpar->sample_rate > 0)
              avpriv_set_pts_info(ast, 64, 1, ast->codecpar->sample_rate);
          // find 'data' chunk
          while(avio_tell(pb) < c->vidpos && !avio_feof(pb)){
              tag = avio_rl32(pb);
              fsize = avio_rl32(pb);
              if(tag == MKTAG('d', 'a', 't', 'a')) break;
              avio_skip(pb, fsize);
          }
          c->bpc = (fsize + c->frames - 1) / c->frames;
          if(ast->codecpar->block_align)
              c->bpc = ((c->bpc + ast->codecpar->block_align - 1) / ast->codecpar->block_align) * ast->codecpar->block_align;
          c->bytes_left = fsize;
          c->wavpos = avio_tell(pb);
          avio_seek(pb, c->vidpos, SEEK_SET);
      }
  
      /* now we are ready: build format streams */
      st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
      st->codecpar->codec_id   = AV_CODEC_ID_DXA;
      st->codecpar->width      = w;
      st->codecpar->height     = h;
      av_reduce(&den, &num, den, num, (1UL<<31)-1);
      avpriv_set_pts_info(st, 33, num, den);
      /* flags & 0x80 means that image is interlaced,
       * flags & 0x40 means that image has double height
       * either way set true height
       */
      if(flags & 0xC0){
          st->codecpar->height >>= 1;
      }
      c->readvid = !c->has_sound;
      c->vidpos  = avio_tell(pb);
      s->start_time = 0;
      s->duration = av_rescale(c->frames, AV_TIME_BASE * (int64_t)num, den);
      av_log(s, AV_LOG_DEBUG, "%d frame(s)\n",c->frames);
  
      return 0;
  }
  
  static int dxa_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      DXAContext *c = s->priv_data;
      int ret;
      uint32_t size;
      uint8_t buf[DXA_EXTRA_SIZE], pal[768+4];
      int pal_size = 0;
  
      if(!c->readvid && c->has_sound && c->bytes_left){
          c->readvid = 1;
          avio_seek(s->pb, c->wavpos, SEEK_SET);
          size = FFMIN(c->bytes_left, c->bpc);
          ret = av_get_packet(s->pb, pkt, size);
          pkt->stream_index = 1;
          if(ret != size)
              return AVERROR(EIO);
          c->bytes_left -= size;
          c->wavpos = avio_tell(s->pb);
          return 0;
      }
      avio_seek(s->pb, c->vidpos, SEEK_SET);
      while(!avio_feof(s->pb) && c->frames){
          uint32_t tag;
          if ((ret = avio_read(s->pb, buf, 4)) != 4) {
              av_log(s, AV_LOG_ERROR, "failed reading chunk type\n");
              return ret < 0 ? ret : AVERROR_INVALIDDATA;
          }
          tag = AV_RL32(buf);
          switch (tag) {
          case MKTAG('N', 'U', 'L', 'L'):
              if ((ret = av_new_packet(pkt, 4 + pal_size)) < 0)
                  return ret;
              pkt->stream_index = 0;
              if(pal_size) memcpy(pkt->data, pal, pal_size);
              memcpy(pkt->data + pal_size, buf, 4);
              c->frames--;
              c->vidpos = avio_tell(s->pb);
              c->readvid = 0;
              return 0;
          case MKTAG('C', 'M', 'A', 'P'):
              pal_size = 768+4;
              memcpy(pal, buf, 4);
              avio_read(s->pb, pal + 4, 768);
              break;
          case MKTAG('F', 'R', 'A', 'M'):
              if ((ret = avio_read(s->pb, buf + 4, DXA_EXTRA_SIZE - 4)) != DXA_EXTRA_SIZE - 4) {
                  av_log(s, AV_LOG_ERROR, "failed reading dxa_extra\n");
                  return ret < 0 ? ret : AVERROR_INVALIDDATA;
              }
              size = AV_RB32(buf + 5);
              if(size > 0xFFFFFF){
                  av_log(s, AV_LOG_ERROR, "Frame size is too big: %"PRIu32"\n",
                         size);
                  return AVERROR_INVALIDDATA;
              }
              ret = av_new_packet(pkt, size + DXA_EXTRA_SIZE + pal_size);
              if (ret < 0)
                  return ret;
              memcpy(pkt->data + pal_size, buf, DXA_EXTRA_SIZE);
              ret = avio_read(s->pb, pkt->data + DXA_EXTRA_SIZE + pal_size, size);
              if(ret != size){
                  return AVERROR(EIO);
              }
              if(pal_size) memcpy(pkt->data, pal, pal_size);
              pkt->stream_index = 0;
              c->frames--;
              c->vidpos = avio_tell(s->pb);
              c->readvid = 0;
              return 0;
          default:
              av_log(s, AV_LOG_ERROR, "Unknown tag %s\n", av_fourcc2str(tag));
              return AVERROR_INVALIDDATA;
          }
      }
      return AVERROR_EOF;
  }
  
  AVInputFormat ff_dxa_demuxer = {
      .name           = "dxa",
      .long_name      = NULL_IF_CONFIG_SMALL("DXA"),
      .priv_data_size = sizeof(DXAContext),
      .read_probe     = dxa_probe,
      .read_header    = dxa_read_header,
      .read_packet    = dxa_read_packet,
  };
  