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• ffmpeg transpose corrupts video [on hold]

  15 décembre 2016, par Victor.dMdB

  I’m trying to set up a transcoding pipeline with ffmpeg C lib, but if I transpose it, the video is corrupted as shown below.

  If I don’t transpose, the video is fine, ie the rest of the pipeline is correctly set up.

  I’m not actually sure what is actually the issue, is it a problem with the pxiel format ? Why is the transpose corrupting the video stream ? Is there something wrong with my code (added below) ?

  

  The constructor (code was taken from here)

  MyFilter::MyFilter(const std::string filter_desc, AVCodecContext *data_ctx){
  
    avfilter_register_all();
  
    buffersrc_ctx = NULL;
  
    buffersink_ctx = NULL;
  
  
  
      filter_graph = avfilter_graph_alloc();
  
  
  
    AVFilter *buffersink = avfilter_get_by_name("buffersink");
  
    if (!buffersink) {
  
      throw error("filtering sink element not found\n");
  
    }
  
  
  
    if (avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out", NULL, NULL, filter_graph) < 0) {
  
      throw error("Cannot create buffer sink\n");
  
    }
  
  
  
  
  
  filterInputs  = avfilter_inout_alloc();
  
    filterInputs->name       = av_strdup("out");
  
    filterInputs->filter_ctx = buffersink_ctx;
  
    filterInputs->pad_idx    = 0;
  
    filterInputs->next       = NULL;
  
  
  
      AVFilter *buffersrc  = avfilter_get_by_name("buffer");
  
      if (!buffersrc) {
  
          throw error("filtering source element not found\n");
  
      }
  
  
  
      char args[512];
  
      snprintf(args, sizeof(args), "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
  
                      data_ctx->width, data_ctx->height, data_ctx->pix_fmt,
  
                      data_ctx->time_base.num, data_ctx->time_base.den,
  
                      data_ctx->sample_aspect_ratio.num, data_ctx->sample_aspect_ratio.den);
  
  
  
      log(Info, "Setting filter input with %s", args);
  
  
  
  
  
      if (avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in", args, NULL, filter_graph) < 0) {
  
           throw error("Cannot create buffer source\n");
  
      }
  
  
  
      filterOutputs = avfilter_inout_alloc();
  
      filterOutputs->name       = av_strdup("in");
  
      filterOutputs->filter_ctx = buffersrc_ctx;
  
      filterOutputs->pad_idx    = 0;
  
      filterOutputs->next       = NULL;
  
  
  
      if ((avfilter_graph_parse(filter_graph, filter_desc.c_str(), filterInputs, filterOutputs, NULL)) < 0)
  
              log(Warning,"Could not parse input filters");
  
  
  
      if ((avfilter_graph_config(filter_graph, NULL)) < 0)
  
          log(Warning,"Could not configure filter graph");
  
  
  
  }

  And the process

  AVFrame * MyFilter::process(AVFrame *inFrame){
  
  
  
      if (av_buffersrc_add_frame_flags(buffersrc_ctx, inFrame->get(), AV_BUFFERSRC_FLAG_PUSH | AV_BUFFERSRC_FLAG_KEEP_REF ) < 0) {
  
           throw error("Error while feeding the filtergraph\n");
  
       }
  
  
  
      int i = 0;
  
      AVFrame* outFrame =  av_frame_alloc();
  
      if( av_buffersink_get_frame(buffersink_ctx, outFrame) < 0 ){
  
       throw error("Couldnt find a frame\n");
  
      }
  
    return outFrame;
  
  }

  And the filter I’m using is :

   std::string filter_desc = "transpose=cclock"

  As an extra note, it seems like the top bar(visible in the screen capture above) is actually composed of properly rotated pixels, and this works for the whole video. It just degrades for the remaining 99% of pixels.

  EDIT :

  Using this works std::string filter_desc = "rotate=1.58", but then the resolution is not properly shifted.

• Grow your business and understand your conversion funnel with Funnels for Piwik

  14 décembre 2016, par InnoCraft — Plugins

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  14 décembre 2016, par InnoCraft — Plugins

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