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ffmpeg-4.2.2/libavcodec/sp5xdec.c 3.71 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * Sunplus JPEG decoder (SP5X)
   * Copyright (c) 2003 Alex Beregszaszi
   *
   * 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
   * Sunplus JPEG decoder (SP5X).
   */
  
  #include "avcodec.h"
  #include "internal.h"
  #include "mjpeg.h"
  #include "mjpegdec.h"
  #include "sp5x.h"
  
  
  static int sp5x_decode_frame(AVCodecContext *avctx,
                                void *data, int *got_frame,
                                AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int buf_size = avpkt->size;
      AVPacket avpkt_recoded;
      const int qscale = 5;
      uint8_t *recoded;
      int i = 0, j = 0;
  
      if (!avctx->width || !avctx->height)
          return -1;
  
      recoded = av_mallocz(buf_size + 1024);
      if (!recoded)
          return -1;
  
      /* SOI */
      recoded[j++] = 0xFF;
      recoded[j++] = 0xD8;
  
      memcpy(recoded+j, &sp5x_data_dqt[0], sizeof(sp5x_data_dqt));
      memcpy(recoded+j+5, &sp5x_quant_table[qscale * 2], 64);
      memcpy(recoded+j+70, &sp5x_quant_table[(qscale * 2) + 1], 64);
      j += sizeof(sp5x_data_dqt);
  
      memcpy(recoded+j, &sp5x_data_dht[0], sizeof(sp5x_data_dht));
      j += sizeof(sp5x_data_dht);
  
      memcpy(recoded+j, &sp5x_data_sof[0], sizeof(sp5x_data_sof));
      AV_WB16(recoded+j+5, avctx->coded_height);
      AV_WB16(recoded+j+7, avctx->coded_width);
      j += sizeof(sp5x_data_sof);
  
      memcpy(recoded+j, &sp5x_data_sos[0], sizeof(sp5x_data_sos));
      j += sizeof(sp5x_data_sos);
  
      if(avctx->codec_id==AV_CODEC_ID_AMV)
          for (i = 2; i < buf_size-2 && j < buf_size+1024-2; i++)
              recoded[j++] = buf[i];
      else
      for (i = 14; i < buf_size && j < buf_size+1024-3; i++)
      {
          recoded[j++] = buf[i];
          if (buf[i] == 0xff)
              recoded[j++] = 0;
      }
  
      /* EOI */
      recoded[j++] = 0xFF;
      recoded[j++] = 0xD9;
  
      av_init_packet(&avpkt_recoded);
      avpkt_recoded.data = recoded;
      avpkt_recoded.size = j;
      i = ff_mjpeg_decode_frame(avctx, data, got_frame, &avpkt_recoded);
  
      av_free(recoded);
  
      return i < 0 ? i : avpkt->size;
  }
  
  #if CONFIG_SP5X_DECODER
  AVCodec ff_sp5x_decoder = {
      .name           = "sp5x",
      .long_name      = NULL_IF_CONFIG_SMALL("Sunplus JPEG (SP5X)"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_SP5X,
      .priv_data_size = sizeof(MJpegDecodeContext),
      .init           = ff_mjpeg_decode_init,
      .close          = ff_mjpeg_decode_end,
      .decode         = sp5x_decode_frame,
      .capabilities   = AV_CODEC_CAP_DR1,
      .max_lowres     = 3,
      .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
  };
  #endif
  #if CONFIG_AMV_DECODER
  AVCodec ff_amv_decoder = {
      .name           = "amv",
      .long_name      = NULL_IF_CONFIG_SMALL("AMV Video"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_AMV,
      .priv_data_size = sizeof(MJpegDecodeContext),
      .init           = ff_mjpeg_decode_init,
      .close          = ff_mjpeg_decode_end,
      .decode         = sp5x_decode_frame,
      .max_lowres     = 3,
      .capabilities   = AV_CODEC_CAP_DR1,
      .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
  };
  #endif