text: /*
   * MxPEG decoder
   * Copyright (c) 2011 Anatoly Nenashev
   *
   * 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
   * MxPEG decoder
   */
  
  #include "mjpeg.h"
  #include "mjpegdec.h"
  
  typedef struct MXpegDecodeContext {
      MJpegDecodeContext jpg;
      AVFrame picture[2]; /* pictures array */
      int picture_index; /* index of current picture */
      int got_sof_data; /* true if SOF data successfully parsed */
      int got_mxm_bitmask; /* true if MXM bitmask available */
      uint8_t *mxm_bitmask; /* bitmask buffer */
      unsigned bitmask_size; /* size of bitmask */
      int has_complete_frame; /* true if has complete frame */
      uint8_t *completion_bitmask; /* completion bitmask of macroblocks */
      unsigned mb_width, mb_height; /* size of picture in MB's from MXM header */
  } MXpegDecodeContext;
  
  static av_cold int mxpeg_decode_init(AVCodecContext *avctx)
  {
      MXpegDecodeContext *s = avctx->priv_data;
  
      s->picture[0].reference = s->picture[1].reference = 3;
      s->jpg.picture_ptr      = &s->picture[0];
      ff_mjpeg_decode_init(avctx);
  
      return 0;
  }
  
  static int mxpeg_decode_app(MXpegDecodeContext *s,
                              const uint8_t *buf_ptr, int buf_size)
  {
      int len;
      if (buf_size < 2)
          return 0;
      len = AV_RB16(buf_ptr);
      skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));
  
      return 0;
  }
  
  static int mxpeg_decode_mxm(MXpegDecodeContext *s,
                              const uint8_t *buf_ptr, int buf_size)
  {
      unsigned bitmask_size, mb_count;
      int i;
  
      s->mb_width  = AV_RL16(buf_ptr+4);
      s->mb_height = AV_RL16(buf_ptr+6);
      mb_count = s->mb_width * s->mb_height;
  
      bitmask_size = (mb_count + 7) >> 3;
      if (bitmask_size > buf_size - 12) {
          av_log(s->jpg.avctx, AV_LOG_ERROR,
                 "MXM bitmask is not complete\n");
          return AVERROR(EINVAL);
      }
  
      if (s->bitmask_size != bitmask_size) {
          s->bitmask_size = 0;
          av_freep(&s->mxm_bitmask);
          s->mxm_bitmask = av_malloc(bitmask_size);
          if (!s->mxm_bitmask) {
              av_log(s->jpg.avctx, AV_LOG_ERROR,
                     "MXM bitmask memory allocation error\n");
              return AVERROR(ENOMEM);
          }
  
          av_freep(&s->completion_bitmask);
          s->completion_bitmask = av_mallocz(bitmask_size);
          if (!s->completion_bitmask) {
              av_log(s->jpg.avctx, AV_LOG_ERROR,
                     "Completion bitmask memory allocation error\n");
              return AVERROR(ENOMEM);
          }
  
          s->bitmask_size = bitmask_size;
      }
  
      memcpy(s->mxm_bitmask, buf_ptr + 12, bitmask_size);
      s->got_mxm_bitmask = 1;
  
      if (!s->has_complete_frame) {
          uint8_t completion_check = 0xFF;
          for (i = 0; i < bitmask_size; ++i) {
              s->completion_bitmask[i] |= s->mxm_bitmask[i];
              completion_check &= s->completion_bitmask[i];
          }
          s->has_complete_frame = !(completion_check ^ 0xFF);
      }
  
      return 0;
  }
  
  static int mxpeg_decode_com(MXpegDecodeContext *s,
                              const uint8_t *buf_ptr, int buf_size)
  {
      int len, ret = 0;
      if (buf_size < 2)
          return 0;
      len = AV_RB16(buf_ptr);
      if (len > 14 && len <= buf_size && !strncmp(buf_ptr + 2, "MXM", 3)) {
          ret = mxpeg_decode_mxm(s, buf_ptr + 2, len - 2);
      }
      skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));
  
      return ret;
  }
  
  static int mxpeg_check_dimensions(MXpegDecodeContext *s, MJpegDecodeContext *jpg,
                                    AVFrame *reference_ptr)
  {
      if ((jpg->width + 0x0F)>>4 != s->mb_width ||
          (jpg->height + 0x0F)>>4 != s->mb_height) {
          av_log(jpg->avctx, AV_LOG_ERROR,
                 "Picture dimensions stored in SOF and MXM mismatch\n");
          return AVERROR(EINVAL);
      }
  
      if (reference_ptr->data[0]) {
          int i;
          for (i = 0; i < MAX_COMPONENTS; ++i) {
              if ( (!reference_ptr->data[i] ^ !jpg->picture_ptr->data[i]) ||
                   reference_ptr->linesize[i] != jpg->picture_ptr->linesize[i]) {
                  av_log(jpg->avctx, AV_LOG_ERROR,
                         "Dimensions of current and reference picture mismatch\n");
                  return AVERROR(EINVAL);
              }
          }
      }
  
      return 0;
  }
  
  static int mxpeg_decode_frame(AVCodecContext *avctx,
                            void *data, int *data_size,
                            AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int buf_size = avpkt->size;
      MXpegDecodeContext *s = avctx->priv_data;
      MJpegDecodeContext *jpg = &s->jpg;
      const uint8_t *buf_end, *buf_ptr;
      const uint8_t *unescaped_buf_ptr;
      int unescaped_buf_size;
      int start_code;
      AVFrame *picture = data;
      int ret;
  
      buf_ptr = buf;
      buf_end = buf + buf_size;
      jpg->got_picture = 0;
      s->got_mxm_bitmask = 0;
      while (buf_ptr < buf_end) {
          start_code = ff_mjpeg_find_marker(jpg, &buf_ptr, buf_end,
                                            &unescaped_buf_ptr, &unescaped_buf_size);
          if (start_code < 0)
              goto the_end;
          {
              init_get_bits(&jpg->gb, unescaped_buf_ptr, unescaped_buf_size*8);
  
              if (start_code >= APP0 && start_code <= APP15) {
                  mxpeg_decode_app(s, unescaped_buf_ptr, unescaped_buf_size);
              }
  
              switch (start_code) {
              case SOI:
                  if (jpg->got_picture) //emulating EOI
                      goto the_end;
                  break;
              case EOI:
                  goto the_end;
              case DQT:
                  ret = ff_mjpeg_decode_dqt(jpg);
                  if (ret < 0) {
                      av_log(avctx, AV_LOG_ERROR,
                             "quantization table decode error\n");
                      return ret;
                  }
                  break;
              case DHT:
                  ret = ff_mjpeg_decode_dht(jpg);
                  if (ret < 0) {
                      av_log(avctx, AV_LOG_ERROR,
                             "huffman table decode error\n");
                      return ret;
                  }
                  break;
              case COM:
                  ret = mxpeg_decode_com(s, unescaped_buf_ptr,
                                         unescaped_buf_size);
                  if (ret < 0)
                      return ret;
                  break;
              case SOF0:
                  s->got_sof_data = 0;
                  ret = ff_mjpeg_decode_sof(jpg);
                  if (ret < 0) {
                      av_log(avctx, AV_LOG_ERROR,
                             "SOF data decode error\n");
                      return ret;
                  }
                  if (jpg->interlaced) {
                      av_log(avctx, AV_LOG_ERROR,
                             "Interlaced mode not supported in MxPEG\n");
                      return AVERROR(EINVAL);
                  }
                  s->got_sof_data = 1;
                  break;
              case SOS:
                  if (!s->got_sof_data) {
                      av_log(avctx, AV_LOG_WARNING,
                             "Can not process SOS without SOF data, skipping\n");
                      break;
                  }
                  if (!jpg->got_picture) {
                      if (jpg->first_picture) {
                          av_log(avctx, AV_LOG_WARNING,
                                 "First picture has no SOF, skipping\n");
                          break;
                      }
                      if (!s->got_mxm_bitmask){
                          av_log(avctx, AV_LOG_WARNING,
                                 "Non-key frame has no MXM, skipping\n");
                          break;
                      }
                      /* use stored SOF data to allocate current picture */
                      if (jpg->picture_ptr->data[0])
                          avctx->release_buffer(avctx, jpg->picture_ptr);
                      if (avctx->get_buffer(avctx, jpg->picture_ptr) < 0) {
                          av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
                          return AVERROR(ENOMEM);
                      }
                      jpg->picture_ptr->pict_type = AV_PICTURE_TYPE_P;
                      jpg->picture_ptr->key_frame = 0;
                      jpg->got_picture = 1;
                  } else {
                      jpg->picture_ptr->pict_type = AV_PICTURE_TYPE_I;
                      jpg->picture_ptr->key_frame = 1;
                  }
  
                  if (s->got_mxm_bitmask) {
                      AVFrame *reference_ptr = &s->picture[s->picture_index ^ 1];
                      if (mxpeg_check_dimensions(s, jpg, reference_ptr) < 0)
                          break;
  
                      /* allocate dummy reference picture if needed */
                      if (!reference_ptr->data[0] &&
                          avctx->get_buffer(avctx, reference_ptr) < 0) {
                          av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
                          return AVERROR(ENOMEM);
                      }
  
                      ff_mjpeg_decode_sos(jpg, s->mxm_bitmask, reference_ptr);
                  } else {
                      ff_mjpeg_decode_sos(jpg, NULL, NULL);
                  }
  
                  break;
              }
  
              buf_ptr += (get_bits_count(&jpg->gb)+7) >> 3;
          }
  
      }
  
  the_end:
      if (jpg->got_picture) {
          *data_size = sizeof(AVFrame);
          *picture = *jpg->picture_ptr;
          s->picture_index ^= 1;
          jpg->picture_ptr = &s->picture[s->picture_index];
  
          if (!s->has_complete_frame) {
              if (!s->got_mxm_bitmask)
                  s->has_complete_frame = 1;
              else
                  *data_size = 0;
          }
      }
  
      return buf_ptr - buf;
  }
  
  static av_cold int mxpeg_decode_end(AVCodecContext *avctx)
  {
      MXpegDecodeContext *s = avctx->priv_data;
      MJpegDecodeContext *jpg = &s->jpg;
      int i;
  
      jpg->picture_ptr = NULL;
      ff_mjpeg_decode_end(avctx);
  
      for (i = 0; i < 2; ++i) {
          if (s->picture[i].data[0])
              avctx->release_buffer(avctx, &s->picture[i]);
      }
  
      av_freep(&s->mxm_bitmask);
      av_freep(&s->completion_bitmask);
  
      return 0;
  }
  
  AVCodec ff_mxpeg_decoder = {
      .name           = "mxpeg",
      .long_name      = NULL_IF_CONFIG_SMALL("Mobotix MxPEG video"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = CODEC_ID_MXPEG,
      .priv_data_size = sizeof(MXpegDecodeContext),
      .init           = mxpeg_decode_init,
      .close          = mxpeg_decode_end,
      .decode         = mxpeg_decode_frame,
      .capabilities   = CODEC_CAP_DR1,
      .max_lowres     = 3
  };
  