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• How to extract 16-bit PNG frame from lossless x264 video

  29 mai 2017, par whiskeyspider

  I encoded a series of 16-bit grayscale PNGs to a lossless video with the following command:

  ffmpeg -i image%04d.png -crf 0 -c:v libx264 -preset veryslow output.mp4
  

  I am now trying to verify that the conversion to video was truly lossless by pulling out the PNGs at the same quality. The command I'm using:

  ffmpeg -i output.mp4 image%04d.png
  

  However, this is outputting 8-bit PNGs. I've tried various options I've read about such as -vcodec png and -qscale 0 but so far nothing appears to make it output 16-bit PNGs.

  How do I extract all frames from the video at the same quality as they were going in? Or did I make a mistake in creating the lossless video in the first place?

  Edit: I get this error message when trying to use -pix_fmt gray16be.

  [swscaler @ 0x7fef1a8f0800] deprecated pixel format used, make sure you did set range correctly

  Full output:

  ffmpeg -i output.mp4 -pix_fmt gray16be  image%04d.png
  ffmpeg version 3.3.1 Copyright (c) 2000-2017 the FFmpeg developers
    built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3.1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
    libavutil      55. 58.100 / 55. 58.100
    libavcodec     57. 89.100 / 57. 89.100
    libavformat    57. 71.100 / 57. 71.100
    libavdevice    57.  6.100 / 57.  6.100
    libavfilter     6. 82.100 /  6. 82.100
    libavresample   3.  5.  0 /  3.  5.  0
    libswscale      4.  6.100 /  4.  6.100
    libswresample   2.  7.100 /  2.  7.100
    libpostproc    54.  5.100 / 54.  5.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.71.100
    Duration: 00:00:09.76, start: 0.000000, bitrate: 1337 kb/s
      Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuvj444p(pc), 512x512, 1336 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
      Metadata:
        handler_name    : VideoHandler
  Stream mapping:
    Stream #0:0 -> #0:0 (h264 (native) -> png (native))
  Press [q] to stop, [?] for help
  [swscaler @ 0x7fef1a8f0800] deprecated pixel format used, make sure you did set range correctly
  Output #0, image2, to 'image%04d.png':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.71.100
      Stream #0:0(und): Video: png, gray16be, 512x512, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc (default)
      Metadata:
        handler_name    : VideoHandler
        encoder         : Lavc57.89.100 png
  frame=  244 fps=0.0 q=-0.0 Lsize=N/A time=00:00:09.76 bitrate=N/A speed=  21x    
  video:4038kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  

  I'm happy to use a non-ffmpeg solution if there is one.

• How can I extract the first frame from a movie AND overlay a watermark on it at the same time ?

  29 mai 2017, par Eric Vasilik

  I want to, with a single ffmpeg command line, extract the first frame from a movie (as a .jpg and sized to fit inside a box of a given size), and overlay a centered PNG on that frame.

  I've run into problems using -vf and -filter_complex at the same time.

• Huge memory leak when filtering video with libavfilter

  29 mai 2017, par Captain Jack

  I have a relatively simple FFMPEG C program, to which a video frame is fed, processed via filter graph and sent to frame renderer.

  Here are some code snippets:

  /* Filter graph here */
  char args[512];
  enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB32 };    
  AVFilterGraph   *filter_graph;
  avfilter_register_all();
  AVFilter *buffersrc  = avfilter_get_by_name("buffer");
  AVFilter *buffersink = avfilter_get_by_name("ffbuffersink");
  AVBufferSinkParams *buffersink_params;
  AVFilterInOut *outputs = avfilter_inout_alloc();
  AVFilterInOut *inputs  = avfilter_inout_alloc();
  filter_graph = avfilter_graph_alloc();
  
  snprintf(args, sizeof(args),
          "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
          av->codec_ctx->width, av->codec_ctx->height, av->codec_ctx->pix_fmt,
          av->codec_ctx->time_base.num, av->codec_ctx->time_base.den,
          av->codec_ctx->sample_aspect_ratio.num, av->codec_ctx->sample_aspect_ratio.den);
  
  if(avfilter_graph_create_filter(&av->buffersrc_ctx, buffersrc, "in",args, NULL, filter_graph) < 0) 
  {
      fprintf(stderr, "Cannot create buffer source\n");
      return(0);
  }
  
   /* buffer video sink: to terminate the filter chain. */
  buffersink_params = av_buffersink_params_alloc();
  buffersink_params->pixel_fmts = pix_fmts;
  
  if(avfilter_graph_create_filter(&av->buffersink_ctx, buffersink, "out",NULL, buffersink_params, filter_graph) < 0) 
  {
      printf("Cannot create buffer sink\n");
      return(HACKTV_ERROR);
  }
  
    /* Endpoints for the filter graph. */
      outputs->name       = av_strdup("in");
      outputs->filter_ctx = av->buffersrc_ctx;
      outputs->pad_idx    = 0;
      outputs->next       = NULL;
  
      inputs->name       = av_strdup("out");
      inputs->filter_ctx = av->buffersink_ctx;
      inputs->pad_idx    = 0;
      inputs->next       = NULL;
  
  const char *filter_descr = "vflip";
  
      if (avfilter_graph_parse_ptr(filter_graph, filter_descr, &inputs, &outputs, NULL) < 0)
  {
      printf("Cannot parse filter graph\n");
      return(0);
  }
  
   if (avfilter_graph_config(filter_graph, NULL) < 0) 
  {
      printf("Cannot configure filter graph\n");
      return(0);
  }
  
  av_free(buffersink_params);
  avfilter_inout_free(&inputs);
  avfilter_inout_free(&outputs);
  

  The above code is called by these elsewhere:

  av->frame_in->pts = av_frame_get_best_effort_timestamp(av->frame_in);
  
  /* push the decoded frame into the filtergraph*/
  if (av_buffersrc_add_frame(av->buffersrc_ctx, av->frame_in) < 0) 
  {
      printf( "Error while feeding the filtdergraph\n");
      break;
   }
  
   /* pull filtered pictures from the filtergraph */ 
   if(av_buffersink_get_frame(av->buffersink_ctx, av->frame_out) < 0) 
   {
        printf( "Error while sourcing the filtergraph\n");
         break;
    }  
  
  /* do stuff with frame */
  

  Now, the code works absolutely fine and the video comes out the way I expect it to (vertically flipped for testing purposes).

  The biggest issue I have is that there is a massive memory leak. An high res video will consume 2Gb in a matter of seconds and crash the program. I traced the leak to this piece of code:

  /* push the decoded frame into the filtergraph*/
  if (av_buffersrc_add_frame(av->buffersrc_ctx, av->frame_in) < 0) 
  

  If I bypass the filter by doing av->frame_out=av->frame_in; without pushing the frame into it (and obviously not pulling from it), there is no leak and memory usage is stable.

  Now, I am very new to C, so be gentle, but it seems like I should be clearing out the buffersrc_ctx somehow but no idea how. I've looked in official documentations but couldn't find anything.

  Can someone advise?

• when i use FFmpeg libary to compress video,ide show this error

  29 mai 2017, par leslie

   E/FFmpeg: Exception while trying to run: /data/user/0/com.example/files/ffmpeg -y -i /storage/emulated/0/DCIM/Camera/VID_20170517_112234.mp4 -vf scale=500:-1 qscale:v 8 -acodec copy -vcodec mpeg4/storage/emulated/0/wobingwoyi/1496060268815.mp4
  
   java.io.IOException: Error running exec(). Command: [/data/user/0/com.wobingwoyi/files/ffmpeg, -y, -i, /storage/emulated/0/DCIM/Camera/VID_20170517_112234.mp4, -vf, scale=500:-1, -qscale:v, 8, -acodec, copy, -vcodec, mpeg4, /storage/emulated/0/wobingwoyi/1496060268815.mp4] Working Directory: null Environment: null
  

  Here is my Configuration

  This is the complete error message

• FFMPEG multi thread decoding

  29 mai 2017, par liran_11

  I'm decoding a multi sliced HEVC video using multi threads (ffmpeg -threads 4 -thread_type slice), and I was wondering, Are there any specific configuration that I should use while encoding in order to improve my results (fps wise)? Maybe some parameters that enable thread per slice work better.

  thanks.