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• How to compress video applying even blur effect

  17 octobre 2016, par Kukuster

  How to compress video applying well-looking apportioned blur effect, like in JPG image ?

  I tried some ffmpeg postprocesing libraries, they are fspp, spp, uspp (takes really long time to render), etc. I almost reached the goal using fspp with parameters 5:60:15 . But blur was stronger than needed, and it’s leave bad artifacts when i try to use less compression. Also uspp is does beautiful and compresses enough, but it’s leave about 50% of video unblured. I also haven’t much time to try all uspp features. Is there resolution special for this purpose ?

  The point is to implement video compression with the only side effect of compression approaches jpeg-compression-like blur or blur-mask-like. Also it would be very good if there is a simple option to choose between :
  1) more compress, less pretty blur / more strong blur ; and 2) less compress, prettier blur / less strong blur.

  I am used to use ffmpeg and i’m running linux, so it would be so nice if there is a way to solve this with ffmpeg.
  Here is my ffmpeg input data about the video streams :

    Duration : 00:01:03.02, start : 0.000000, bitrate : 4010 kb/s
      Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 3870 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
      Metadata :
        handler_name : VideoHandler
      Stream #0:1(eng) : Audio : aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 133 kb/s (default)
      Metadata :
        handler_name : SoundHandler
  

  Edit : attaching jpeg pictured as example of desired output :
  
  

• ffprobe not showing language tag for ASS files in Ubuntu

  9 juillet 2023, par Efraín

  This is something that has me totally lost, because I'm not sure what could I have done, but from one week to another, "language" stopped appearing in the tags of an ASS track on a MKV. I know this just started to appear, because just last week I ended working on an script to detect the language of tracks, and today that I decided to test it again, I noted that it started to fail, and from my debug it's because ffprobe is now printing this

  


  {
    "index": 2,
    "codec_name": "ass",
    "codec_long_name": "ASS (Advanced SSA) subtitle",
    "codec_type": "subtitle",
    "codec_tag_string": "[0][0][0][0]",
    "codec_tag": "0x0000",
    "r_frame_rate": "0/0",
    "avg_frame_rate": "0/0",
    "time_base": "1/1000",
    "start_pts": 0,
    "start_time": "0.000000",
    "duration_ts": 1430816,
    "duration": "1430.816000",
    "disposition": {
        "default": 1,
        "dub": 0,
        "original": 0,
        "comment": 0,
        "lyrics": 0,
        "karaoke": 0,
        "forced": 0,
        "hearing_impaired": 0,
        "visual_impaired": 0,
        "clean_effects": 0,
        "attached_pic": 0,
        "timed_thumbnails": 0
    },
    "tags": {
        "BPS-eng": "85",
        "DURATION-eng": "00:23:34.830000000",
        "NUMBER_OF_FRAMES-eng": "262",
        "NUMBER_OF_BYTES-eng": "15128",
        "_STATISTICS_WRITING_APP-eng": "mkvmerge v40.0.0 ('Old Town Road + Pony') 32-bit",
        "_STATISTICS_WRITING_DATE_UTC-eng": "2023-07-02 11:29:54",
        "_STATISTICS_TAGS-eng": "BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES"
    }
}


  


  Where it should be a field called "language" in the "tags", like this(Note that other file types, like SRT, or audio tracks show it correctly)

  


  "tags": {
    "language": "eng",
    "BPS-eng": "128000",
    "DURATION-eng": "00:23:50.813000000",
    "NUMBER_OF_FRAMES-eng": "61620",
    "NUMBER_OF_BYTES-eng": "22893018",
    "_STATISTICS_WRITING_APP-eng": "mkvmerge v40.0.0 ('Old Town Road + Pony') 32-bit",
    "_STATISTICS_WRITING_DATE_UTC-eng": "2023-07-02 11:29:54",
    "_STATISTICS_TAGS-eng": "BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES"
}


  


  The weird part is that is the same file I used for testing(And it worked), and I haven't edited it, so I'm not sure why is this happening, Does someone knows if I might have messed up something installing a library for another thing that might have caused it ?

  


  Just in case is necessary, this is the command I use : ffprobe -v quiet -print_format json -show_streams <file></file>

  


• Linking ffmpeg's libswresample from MacOS X 10.9 with C++

  8 janvier 2014, par user2530102

  I am trying to link to ffmpeg's libswresample from a C++ application. I have installed ffmpeg through Homebrew on Mac OS X 10.9. A simple test application links if it's compiled as C, but not if it's compiled as C++. Here is the sample code :

  #include 
  
  #include <libswresample></libswresample>swresample.h>
  
  
  
  int main()
  
  {
  
    swr_alloc();
  
    printf("Hello world\n");
  
    return 0;
  
  }

  When compiled as C with clang -I/usr/local/include -L/usr/local/lib -lswresample -o hello hello.c this creates the application as expected. When compiled with C++ using clang++ -I/usr/local/include -L/usr/local/lib -lswresample -o hello hello.cc it results in an error like the following :

  Undefined symbols for architecture x86_64:
  
    "swr_alloc()", referenced from:
  
        _main in hello-9jqOY4.o
  
  ld: symbol(s) not found for architecture x86_64
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

  But running nm -a /usr/local/lib/libswresample.dylib includes 000000000000d8a9 T _swr_alloc and file /usr/local/lib/libswresample.dylib shows /usr/local/lib/libswresample.dylib: Mach-O 64-bit dynamically linked shared library x86_64 which I assume is expected. I have the same issue compiling the example with gcc/g++, and I also have the same issue when compiling ffmpeg with either clang or gcc, which leads me to think that there is just something I don't know about linking that should be obvious, but I haven't found any references suggesting that it should be different linking a library in C++ vs. C, and linking other libraries (sox, for example) presents no difficulties with an identical setup.

  I have seen posts related to linking issues in Mac OS X 10.9 because of the change from libstdc++ to libc++, but adding -stdlib=libstdc++ or -stdlib=libc++ seems to make no difference. It also makes no difference to add -mmacosx-version-min=10.6 or 10.9.

  Any help is greatly appreciated.