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• FFMPEG : sws_scale returns error : Slice parameters 0, 2160 are invalid

  21 janvier 2020, par Matthew Czarnek

  I’m trying to follow a tutorial to display ffmpeg AVFrame output in SDL. The tutorial(and all examples I’m seeing online) are still using ’sws_getContext’, which has been deprecated and removed from the newest version of ffmpeg. Trying to change current pixel format from whatever it currently is to PIX_FMT_YUV420P, so I can display it. I believe I need the sws_scale function to accomplish this.

  However, sws_scale is the function that causes a command line error of :
  Slice parameters 0, 2160 are invalid

  Here is all my code associate with swsContext :

  struct SwsContext* av_sws_ctx = NULL;
  
  av_sws_ctx = sws_alloc_context();
  
  
  
  sws_init_context(av_sws_ctx, NULL, NULL);
  
  
  
  sws_scale(av_sws_ctx, (uint8_t const* const*)av_frame->data,
  
                          av_frame->linesize, 0, av_codec_context->height,
  
                          av_frame->data, av_frame->linesize);

  Further complicating the matter, SwsContext is only defined internal to ffmpeg, externally I can’t set/get any variables or even view them in the debugger.

  int sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[], const int srcStride[], int srcSliceY, int srcSliceH, uint8_t *const dst[], const int dstStride[] )

  The vales of other parameters, other than av_sws_ctx :

  srcSlice: av_frame->data = 
  
       8 arrays, first is filled with "\x10\x10\x10\x10\x10..."
  
       second and third are "€€€€€€€€€€€€€€€€€..."
  
       rest are NULL
  
  linesize(av_frame->linesize) is an array:
  
      3840,1920,1920,0,0,0,0,0
  
  srcSliceY:0
  
  srcSliceH:2160
  
  dest: same as second parameter (av_frame->data)
  
  dstStride: av_frame->linesize again

  If I drill into sws_scale source code, I find that this error is thrown by this chunk of code :

  if ((srcSliceY & (macro_height-1)) ||
  
          ((srcSliceH& (macro_height-1)) && srcSliceY + srcSliceH != c->srcH) ||
  
          srcSliceY + srcSliceH > c->srcH) {
  
          av_log(c, AV_LOG_ERROR, "Slice parameters %d, %d are invalid\n", srcSliceY, srcSliceH);
  
          return AVERROR(EINVAL);
  
      }

  I assume that the issue therefore is that the height of my video is bigger than sws_context(4k video). But can’t figure out how to tell sws_context what it’s height should be using sws_alloc_context or sws_init_context or any other function.

  See something I’m missing ? Thank you.

• PHP Create video thumbnail with FFMPEG - returns error code 1

  27 février 2013, par Light

  I am trying to create a video thumbnail with FFMPEG using the following script.
  However I am getting return value of 1. What does it mean ? What is error code 1 ? I have Googled it and didn't find and answer. Thanks.
  Here is the code :

  <?php
  
  
  
          //thumb path should be added in the below code
  
          //test for thumb
  
          $dir_img='uploads/';
  
          $mediapath='thumb.jpg';
  
          $file_thumb=create_movie_thumb('test.mp4',$mediapath,$mediaid);
  
  
  
          $name_file=explode(".",$mediapath);
  
          $imgname="thumb_".$name_file[0].".jpg";     
  
  
  
          /*
  
            Function to create video thumbnail using ffmpeg
  
          */
  
          function create_movie_thumb($src_file,$mediapath,$mediaid)
  
          {
  
  
  
              global $CONFIG, $ERROR;
  
  
  
              $CONFIG['ffmpeg_path'] = '/usr/bin/'; // Change the path according to your server.
  
              $dir_img='uploads/';
  
              $CONFIG['fullpath'] = $dir_img."thumbs/";
  
  
  
              $src_file = $src_file;
  
              $name_file=explode(".",$mediapath);
  
              $imgname="thumb_".$name_file[0].".jpg";
  
              $dest_file = $CONFIG['fullpath'].$imgname;
  
  
  
              if (preg_match("#[A-Z]:|\\\\#Ai", __FILE__)) {
  
                  // get the basedir, remove '/include'
  
                  $cur_dir = substr(dirname(__FILE__), 0, -8);
  
                  $src_file = '"' . $cur_dir . '\\' . strtr($src_file, '/', '\\') . '"';
  
                  $ff_dest_file = '"' . $cur_dir . '\\' . strtr($dest_file, '/', '\\') . '"';
  
              } else {
  
                  $src_file = escapeshellarg($src_file);
  
                  $ff_dest_file = escapeshellarg($dest_file);
  
              }
  
  
  
              $output = array();
  
  
  
              if (eregi("win",$_ENV['OS'])) {
  
                  // Command to create video thumb
  
                  $cmd = "\"".str_replace("\\","/", $CONFIG['ffmpeg_path'])."ffmpeg\" -i ".str_replace("\\","/" ,$src_file )." -an -ss 00:00:05 -r 1 -vframes 1 -y ".str_replace("\\","/" ,$ff_dest_file);
  
                  exec ("\"$cmd\"", $output, $retval);
  
                  echo "exec1";
  
  
  
              } else {
  
                  // Command to create video thumb
  
                  $cmd = "{$CONFIG['ffmpeg_path']}ffmpeg -i $src_file -an -ss 00:00:05 -r 1 -vframes 1 -y $ff_dest_file";
  
                  exec ($cmd, $output, $retval);
  
                  echo "exec2";
  
              }
  
  
  
  
  
              if ($retval) {
  
                  $ERROR = "Error executing FFmpeg - Return value: $retval";
  
                  if ($CONFIG['debug_mode']) {
  
                      // Re-execute the command with the backtick operator in order to get all outputs
  
                      // will not work if safe mode is enabled
  
                      $output = `$cmd 2>&1`;
  
                      $ERROR .= "<br /><br /><div align="\&quot;left\&quot;">Cmd line : <br /><span style="&quot;font-size:120%&quot;">" . nl2br(htmlspecialchars($cmd)) . "</span></div>";
  
                      $ERROR .= "<br /><br /><div align="\&quot;left\&quot;">The ffmpeg program said:<br /><span style="&quot;font-size:120%&quot;">";
  
                      $ERROR .= nl2br(htmlspecialchars($output));
  
                      $ERROR .= "</span></div>";
  
                  }
  
                  echo $ERROR;
  
                  @unlink($dest_file);
  
                  return false;
  
              }
  
  
  
              $return = $dest_file;
  
              //@chmod($return, octdec($CONFIG[&#39;default_file_mode&#39;])); //silence the output in case chmod is disabled
  
              return $return;
  
          } 
  
  ?>

• Output black when I decode h264 720p with ffmpeg

  6 décembre 2017, par José Marqueses Saxo

  First, sorry for my english. When I decode h264 720p in ardrone2.0 my output is black and I cant see anything.

  I have try to change the value of pCodecCtx->pix_fmt = AV_PIX_FMT_BGR24; to pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P; and the value of pCodecCtxH264->pix_fmt = AV_PIX_FMT_BGR24; to pCodecCtxH264->pix_fmt = AV_PIX_FMT_YUV420P; but my program crash. What am I doing wrong ?. Thank you, see part of my code :

  av_register_all();
  
  avcodec_register_all();
  
  avformat_network_init();
  
  
  
  // 1.2. Open video file
  
  if(avformat_open_input(&pFormatCtx, drone_addr, NULL, NULL) != 0) {
  
    mexPrintf("No conecct with Drone");
  
    EndVideo();
  
    return;
  
  }
  
  
  
  pCodec    = avcodec_find_decoder(AV_CODEC_ID_H264);
  
  
  
  pCodecCtx = avcodec_alloc_context3(pCodec);
  
  pCodecCtx->pix_fmt = AV_PIX_FMT_BGR24;
  
  pCodecCtx->skip_frame = AVDISCARD_DEFAULT;
  
  pCodecCtx->error_concealment = FF_EC_GUESS_MVS | FF_EC_DEBLOCK;
  
  pCodecCtx->err_recognition = AV_EF_CAREFUL;
  
  pCodecCtx->skip_loop_filter = AVDISCARD_DEFAULT;
  
  pCodecCtx->workaround_bugs = FF_BUG_AUTODETECT;
  
  pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
  
  pCodecCtx->codec_id = AV_CODEC_ID_H264;
  
  pCodecCtx->skip_idct = AVDISCARD_DEFAULT;
  
  pCodecCtx->width = 1280;
  
  pCodecCtx->height = 720;
  
  
  
  pCodecH264 = avcodec_find_decoder(AV_CODEC_ID_H264);
  
  pCodecCtxH264 = avcodec_alloc_context3(pCodecH264);
  
  
  
  
  
  pCodecCtxH264->pix_fmt = AV_PIX_FMT_BGR24;
  
  pCodecCtxH264->skip_frame = AVDISCARD_DEFAULT;
  
  pCodecCtxH264->error_concealment = FF_EC_GUESS_MVS | FF_EC_DEBLOCK;
  
  pCodecCtxH264->err_recognition = AV_EF_CAREFUL;
  
  pCodecCtxH264->skip_loop_filter = AVDISCARD_DEFAULT;
  
  pCodecCtxH264->workaround_bugs = FF_BUG_AUTODETECT;
  
  pCodecCtxH264->codec_type = AVMEDIA_TYPE_VIDEO;
  
  pCodecCtxH264->codec_id = AV_CODEC_ID_H264;
  
  pCodecCtxH264->skip_idct = AVDISCARD_DEFAULT;
  
  
  
  if(avcodec_open2(pCodecCtxH264, pCodecH264, &optionsDict) < 0)
  
  {
  
     mexPrintf("Error opening H264 codec");
  
     return ;
  
  }
  
  
  
  pFrame_BGR24 = av_frame_alloc();
  
  
  
  
  
  if(pFrame_BGR24 == NULL) {
  
     mexPrintf("Could not allocate pFrame_BGR24\n");
  
     return ;
  
  }
  
  
  
  // Determine required buffer size and allocate buffer
  
  
  
  buffer_BGR24 = 
  
  (uint8_t *)av_mallocz(av_image_get_buffer_size(AV_PIX_FMT_BGR24, 
  
  pCodecCtx->width, ((pCodecCtx->height == 720) ? 720 : pCodecCtx->height) * 
  
  sizeof(uint8_t)*3,1));
  
  
  
  // Assign buffer to image planes
  
  
  
  av_image_fill_arrays(pFrame_BGR24->data, pFrame_BGR24->linesize,
  
  buffer_BGR24,AV_PIX_FMT_BGR24, pCodecCtx->width, pCodecCtx->height,1);
  
  
  
  // format conversion context
  
  pConvertCtx_BGR24 = sws_getContext(pCodecCtx->width, pCodecCtx->height, 
  
  pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height,  AV_PIX_FMT_BGR24, 
  
                                   SWS_BILINEAR | SWS_ACCURATE_RND, 0, 0, 0);
  
  
  
  // 1.6. get video frames
  
  pFrame = av_frame_alloc();
  
  
  
  av_init_packet(&packet);
  
  packet.data = NULL;
  
  packet.size = 0;
  
  }
  
  
  
  //Captura un frame
  
  void video::capture(mxArray *plhs[]) {
  
  
  
    if(av_read_frame(pFormatCtx, &packet) < 0){
  
        mexPrintf("Error al leer frame");
  
        return;
  
    }
  
     do {
  
         do {
  
            rest = avcodec_send_packet(pCodecCtxH264, &packet);
  
         } while(rest == AVERROR(EAGAIN));
  
  
  
         if(rest == AVERROR_EOF || rest == AVERROR(EINVAL)) {
  
                  printf("AVERROR(EAGAIN): %d, AVERROR_EOF: %d, 
  
                  AVERROR(EINVAL): %d\n", AVERROR(EAGAIN), AVERROR_EOF, 
  
                  AVERROR(EINVAL));
  
              printf("fe_read_frame: Frame getting error (%d)!\n", rest);
  
              return;
  
         }
  
  
  
         rest = avcodec_receive_frame(pCodecCtxH264, pFrame);
  
     } while(rest == AVERROR(EAGAIN));
  
  
  
     if(rest == AVERROR_EOF || rest == AVERROR(EINVAL)) {
  
  
  
      // An error or EOF occured,index break out and return what
  
      // we have so far.
  
        printf("AVERROR(EAGAIN): %d, AVERROR_EOF: %d, AVERROR(EINVAL): %d\n", 
  
        AVERROR(EAGAIN), AVERROR_EOF, AVERROR(EINVAL));
  
          printf("fe_read_frame: EOF or some othere decoding error (%d)!\n", 
  
          rest);
  
          return;
  
     }
  
  
  
  
  
     // 2.1.1. convert frame to GRAYSCALE [or BGR] for OpenCV
  
     sws_scale(pConvertCtx_BGR24,   (const uint8_t* const*)pFrame->data, 
  
         pFrame->linesize, 0,pCodecCtx->height,   pFrame_BGR24->data,   
  
               pFrame_BGR24->linesize);
  
  //}
  
     av_packet_unref(&packet);
  
     av_init_packet(&packet);
  
     mwSize dims[] = {(pCodecCtx->width)*((pCodecCtx->height == 720) ? 720 : 
  
     pCodecCtx->height)*sizeof(uint8_t)*3};
  
     plhs[0] = mxCreateNumericArray(1,dims,mxUINT8_CLASS, mxREAL);
  
      //plhs[0]=mxCreateDoubleMatrix(pCodecCtx->height,pCodecCtx-
  
      >width,mxREAL);
  
     point=mxGetPr(plhs[0]);
  
     memcpy(point, pFrame_BGR24->data[0],(pCodecCtx->width)*(pCodecCtx-
  
      >height)*sizeof(uint8_t)*3);
  
  }