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• Cygwin64 build of ffmpeg doesn't burn subtitles correctly

  22 août 2014, par Witiko

  I’m using a cygwin64 build of ffmpeg (1, 2) to burn subtitles into a video file as follows :

  $ ffmpeg -i file.mp4 -vf subtitles=file.srt file.ts
  
  ffmpeg version 1.2.3 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Sep 18 2013 01:11:22 with gcc 4.8.1 (GCC)
  
    configuration: --prefix=/usr --libdir=/usr/lib --shlibdir=/usr/bin --incdir=/usr/include --mandir=/usr/share/man --disable-static --enable-shared --enable-gpl --enable-version3 --enable-postproc --enable-swscale --enable-avfilter --enable-pthreads --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcdio --enable-libcelt --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libtwolame --disable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --disable-libxavs --enable-openal --enable-x11grab --enable-zlib --disable-debug --disable-optimizations --enable-yasm --disable-stripping
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'file.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 2013-07-18 23:29:41
  
      encoder         : Lavf51.12.1
  
    Duration: 00:21:59.66, start: 0.000000, bitrate: 5461 kb/s
  
      Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 5135 kb/s, 59.94 fps, 59.94 tbr, 60k tbn, 119.88 tbc
  
      Metadata:
  
        creation_time   : 2013-07-19 02:21:28
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 319 kb/s
  
      Metadata:
  
        creation_time   : 2013-07-19 02:21:28
  
        handler_name    : SoundHandler
  
  [srt @ 0x600057e80] Estimating duration from bitrate, this may be inaccurate
  
  Output #0, mpegts, to 'file.ts':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf54.63.104
  
      Stream #0:0(eng): Video: mpeg2video, yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 59.94 tbc
  
      Metadata:
  
        creation_time   : 2013-07-19 02:21:28
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: mp2, 48000 Hz, stereo, s16, 128 kb/s
  
      Metadata:
  
        creation_time   : 2013-07-19 02:21:28
  
        handler_name    : SoundHandler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 -> mpeg2video)
  
    Stream #0:1 -> #0:1 (aac -> mp2)
  
  Press [q] to stop, [?] for help
  
  [Parsed_subtitles_0 @ 0x6000229c0] Neither PlayResX nor PlayResY defined. Assuming 384x288

  But the subtitles do not appear in the resulting video stream at all.

  The [Parsed_subtitles_0 @ 0x6000229c0] Neither PlayResX nor PlayResY defined. Assuming 384x288 warning is not a part of the problem, as converting the subtitles to .ass via ffmpeg -i file.srt file.ass and specifying the PlayResX and Y values makes the warning disappear without solving the original issue.

  I know that the libass library, which provides the subtitles filter to ffmpeg, uses fontconfig, which is known not to work out-of-box under windows. However, the lack of any fontconfig warnings makes me believe that this is not the problem here. Any leads as to what might the cause of the problem be ?

  EDIT : I have downloaded and compiled ffmpeg myself :

  $ git clone git://source.ffmpeg.org/ffmpeg.git ffmpeg
  
  $ cd ffmpeg
  
  $ ./configure --enable-static --disable-shared --enable-libass
  
  $ make

  The output of the conversion ./ffmpeg -i file.mp4 -vf subtitles=file.srt file.ts is identical except for the fact that no warning messages get printed this time around. I’m looking into whether the fontconfig library configuration could be the culprit.

• ffmpeg webcam stream on windows to sdl

  17 janvier 2021, par user3705497

  Hi I am trying to display webcam stream on windows.

  


  I can use "ffplay" but I want to use "ffmpeg" command.

  


  c:\>ffmpeg -f dshow -i video="USB2.0 VGA UVC WebCam" -f sdl test
ffmpeg version 2020-12-27-git-bff6fbead8-full_build-www.gyan.dev Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.2.0 (Rev5, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      56. 62.100 / 56. 62.100
  libavcodec     58.115.102 / 58.115.102
  libavformat    58. 65.100 / 58. 65.100
  libavdevice    58. 11.103 / 58. 11.103
  libavfilter     7. 94.100 /  7. 94.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, dshow, from 'video=USB2.0 VGA UVC WebCam':
  Duration: N/A, start: 92136.240000, bitrate: N/A
    Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 30 fps, 30 tbr, 10000k tbn, 10000k tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> rawvideo (native))
Press [q] to stop, [?] for help
Output #0, sdl,sdl2, to 'test':
  Metadata:
    encoder         : Lavf58.65.100
    Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422(progressive), 640x480, q=2-31, 147456 kb/s, 30 fps, 30 tbn
    Metadata:
      encoder         : Lavc58.115.102 rawvideo
av_interleaved_write_frame(): Operation not permitted
frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.03 bitrate=N/A speed=0.448x
video:600kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Conversion failed!


  


  The following works though :

  


  ffmpeg -i file.webm -f sdl test


  


  Any ideas why the failure ?

  


• AVI compression with ffmpeg while maintaining alpha channel, to use in Adobe Premiere

  12 décembre 2020, par Dsrts

  I am a novice when it comes to handling video conversion/encoding in general, but have spent a few days trying to figure out if ffmpeg, or any other method out there, is able to compress an .avi that has rgb+a. I have been able to get a few files that appear to work when played in VLC, but they wont load into Adobe Premiere to verify that alpha was maintained, and I assume it is a codec issue and/or a pixel format issue, but so far I haven't been able to pinpoint it.

  


  Also, I'm not sure if it's advisable to compress an .avi at all with alpha since it could lead to quality issues from compression. Some loss of quality is ok if it means reducing file size.

  


  My goal is to convert an avi file to a smaller video file, that isn't multiple GB in size. Currently I have 8 sec transparent lower thirds file that is about 2GB in size. Simply adjusting bitrate has not done it, as that seems to wipe out the alpha channel and I end up with RGB with a white background. I have tried using a PNG codec, with various different pixel formats. This yielded files that would open in VLC, but not Adobe Premiere. I suspect that this has something to do with the codec, though as to what it is, I have no idea.

  


  Right now, this seems like it may just not be possible. Here are some examples of what I have tried :

  


  ffmpeg -i "input.avi" -map 0 -c:v png -c:a copy "Compressed.avi"

  


  —this just creates a file that opens in vlc, but not premiere

  


  ffmpeg.exe -i "input.avi" -vcodec png -b:v 64k -pix_fmt rgb32 "Compressed.avi"

  


  —this does the same thing as above, I tried every pixel format on this list with no success.

  


  ffmpeg.exe -i "input.avi" -b:v 64k -pix_fmt bgr32 "Compressed.avi"

  


  —this just results in an avi with a white background, kills alpha.

  


  That is the closest I have come. The bitrate value is likely arbitrary, as I have also tried with and without bitrate modification. I don't know if there is a way to get Premiere to recognize the files that did open in VLC with the PNG codec, or if there is something I am missing, OR if this is just entirely impossible. The output doesn't need to be .avi either, so long as it will open in Premiere.

  


  —
Edit : Requested in the comments, output from ffmpeg -i input.avi

  


  ffmpeg version 4.3.1-2020-11-19-essentials_build-www.gyan.dev Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.2.0 (Rev5, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, avi, from 'input.avi':
  Metadata:
    date            : 2020-12-09T20:27:57.080928
  Duration: 00:00:10.00, start: 0.000000, bitrate: 1990700 kb/s
    Stream #0:0: Video: rawvideo, bgra, 1920x1080, 1997313 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
At least one output file must be specified


  


  — Edit 2 :
Tried this from the comment and it results in a .mov with preserved alpha but it picks up the white pixel values from text drop shadows, resulting in an outer glow effect instead :

  


  ffmpeg -i "input.avi" -map 0 -pix_fmt rgba -c:v png -c:a copy "compressed.mov"

  


  I also tried the following, and I get dropped frames in addition to similar transparency issues in the drop shadow :

  


  ffmpeg -i "input.avi" -map 0 -pix_fmt rgba -c:v qtrle -c:a copy "compressed.mov"