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ffmpeg-4.2.2/libavcodec/m101.c 4.09 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * Copyright (c) 2016 Michael Niedermayer
   *
   * 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 "libavutil/intreadwrite.h"
  
  #include "avcodec.h"
  #include "internal.h"
  
  
  static av_cold int m101_decode_init(AVCodecContext *avctx)
  {
      if (avctx->extradata_size < 6*4) {
          avpriv_request_sample(avctx, "Missing or too small extradata (size %d)", avctx->extradata_size);
          return AVERROR_INVALIDDATA;
      }
  
      if (avctx->extradata[2*4] == 10)
          avctx->pix_fmt = AV_PIX_FMT_YUV422P10;
      else if (avctx->extradata[2*4] == 8) {
          avctx->pix_fmt = AV_PIX_FMT_YUYV422;
      } else {
          avpriv_request_sample(avctx, "BPS %d", avctx->extradata[2*4]);
          return AVERROR_INVALIDDATA;
      }
  
      return 0;
  }
  
  static int m101_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                        AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int stride, ret;
      int x, y;
      int min_stride = 2 * avctx->width;
      int bits = avctx->extradata[2*4];
      AVFrame *frame = data;
  
      if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
          return ret;
      frame->pict_type = AV_PICTURE_TYPE_I;
      frame->key_frame = 1;
  
      stride = AV_RL32(avctx->extradata + 5*4);
  
      if (avctx->pix_fmt == AV_PIX_FMT_YUV422P10)
          min_stride = (avctx->width + 15) / 16 * 40;
  
      if (stride < min_stride || avpkt->size < stride * (uint64_t)avctx->height) {
          av_log(avctx, AV_LOG_ERROR, "stride (%d) is invalid for packet sized %d\n",
                 stride, avpkt->size);
          return AVERROR_INVALIDDATA;
      }
  
      frame->interlaced_frame = ((avctx->extradata[3*4] & 3) != 3);
      if (frame->interlaced_frame)
          frame->top_field_first = avctx->extradata[3*4] & 1;
  
      for (y = 0; y < avctx->height; y++) {
          int src_y = y;
          if (frame->interlaced_frame)
              src_y = ((y&1)^frame->top_field_first) ? y/2 : (y/2 + avctx->height/2);
          if (bits == 8) {
              uint8_t *line = frame->data[0] + y*frame->linesize[0];
              memcpy(line, buf + src_y*stride, 2*avctx->width);
          } else {
              int block;
              uint16_t *luma = (uint16_t*)&frame->data[0][y*frame->linesize[0]];
              uint16_t *cb   = (uint16_t*)&frame->data[1][y*frame->linesize[1]];
              uint16_t *cr   = (uint16_t*)&frame->data[2][y*frame->linesize[2]];
              for (block = 0; 16*block < avctx->width; block ++) {
                  const uint8_t *buf_src = buf + src_y*stride + 40*block;
                  for (x = 0; x < 16 && x + 16*block < avctx->width; x++) {
                      int xd = x + 16*block;
                      if (x&1) {
                          luma [xd] = (4*buf_src[2*x + 0]) + ((buf_src[32 + (x>>1)]>>4)&3);
                      } else {
                          luma [xd] = (4*buf_src[2*x + 0]) +  (buf_src[32 + (x>>1)]    &3);
                          cb[xd>>1] = (4*buf_src[2*x + 1]) + ((buf_src[32 + (x>>1)]>>2)&3);
                          cr[xd>>1] = (4*buf_src[2*x + 3]) +  (buf_src[32 + (x>>1)]>>6);
                      }
                  }
              }
          }
      }
  
      *got_frame = 1;
      return avpkt->size;
  }
  
  AVCodec ff_m101_decoder = {
      .name           = "m101",
      .long_name      = NULL_IF_CONFIG_SMALL("Matrox Uncompressed SD"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_M101,
      .init           = m101_decode_init,
      .decode         = m101_decode_frame,
      .capabilities   = AV_CODEC_CAP_DR1,
  };