Recherche avancée

Sur d’autres sites (11091)

• Creating GIF from QImages with ffmpeg

  17 août 2016, par Sierra

  I would like to generate GIF from QImage, using ffmpeg - all of that programmatically (C++). I’m working with Qt 5.6 and the last build of ffmpeg (build git-0a9e781 (2016-06-10).

  I’m already able to convert these QImage in .mp4 and it works. I tried to use the same principle for the GIF, changing format pixel and codec. GIF is generated with two pictures (1 second each), in 15 FPS.

  ## INITIALIZATION
  
  #####################################################################
  
  
  
  // Filepath : "C:/Users/.../qt_temp.Jv7868.gif"  
  
  // Allocating an AVFormatContext for an output format...
  
  avformat_alloc_output_context2(formatContext, NULL, NULL, filepath);
  
  
  
  ...
  
  
  
  // Adding the video streams using the default format codecs and initializing the codecs.
  
  stream = avformat_new_stream(formatContext, *codec);
  
  
  
  AVCodecContext * codecContext = avcodec_alloc_context3(*codec);
  
  
  
  context->codec_id       = codecId;
  
  context->bit_rate       = 400000;
  
  ...
  
  context->pix_fmt        = AV_PIX_FMT_BGR8;
  
  
  
  ...
  
  
  
  // Opening the codec...
  
  avcodec_open2(codecContext, codec, NULL);
  
  
  
  ...
  
  
  
  frame = allocPicture(codecContext->width, codecContext->height, codecContext->pix_fmt);
  
  tmpFrame = allocPicture(codecContext->width, codecContext->height, AV_PIX_FMT_RGBA);
  
  
  
  ...
  
  
  
  avformat_write_header(formatContext, NULL);
  
  
  
  ## ADDING A NEW FRAME
  
  #####################################################################
  
  
  
  // Getting in parameter the QImage: newFrame(const QImage & image)
  
  const qint32 width  = image.width();
  
  const qint32 height = image.height();
  
  
  
  // Converting QImage into AVFrame
  
  for (qint32 y = 0; y < height; y++) {
  
      const uint8_t * scanline = image.scanLine(y);
  
  
  
      for (qint32 x = 0; x < width * 4; x++) {
  
          tmpFrame->data[0][y * tmpFrame->linesize[0] + x] = scanline[x];
  
      }
  
  }
  
  
  
  ...
  
  
  
  // Scaling...
  
  if (codec->pix_fmt != AV_PIX_FMT_BGRA) {
  
      if (!swsCtx) {
  
          swsCtx = sws_getContext(codec->width, codec->height,
  
                                  AV_PIX_FMT_BGRA,
  
                                  codec->width, codec->height,
  
                                  codec->pix_fmt,
  
                                  SWS_BICUBIC, NULL, NULL, NULL);
  
      }
  
  
  
      sws_scale(swsCtx,
  
                (const uint8_t * const *)tmpFrame->data,
  
                tmpFrame->linesize,
  
                0,
  
                codec->height,
  
                frame->data,
  
                frame->linesize);
  
  }
  
  frame->pts = nextPts++;
  
  
  
  ...
  
  
  
  int gotPacket = 0;
  
  AVPacket packet = {0};
  
  
  
  av_init_packet(&packet);
  
  avcodec_encode_video2(codec, &packet, frame, &gotPacket);
  
  
  
  if (gotPacket) {
  
      av_packet_rescale_ts(paket, *codec->time_base, stream->time_base);
  
      paket->stream_index = stream->index;
  
  
  
      av_interleaved_write_frame(formatContext, paket);
  
  }

  But when I’m trying to modify the video codec and pixel format to match with GIF specifications, I’m facing some issues.
  I tried several codecs such as AV_CODEC_ID_GIF and AV_CODEC_ID_RAWVIDEO but none of them seem to work. During the initialization phase, avcodec_open2() always returns such kind of errors :

  Specified pixel format rgb24 is invalid or not supported
  
  Could not open video codec:  gif

  EDIT 17/06/2016

  Digging a little bit more, avcodec_open2() returns -22 :

  #define EINVAL          22      /* Invalid argument */

  EDIT 22/06/2016

  Here are the flags used to compile ffmpeg :

  "FFmpeg/Libav configuration: --disable-static --enable-shared --enable-gpl --enable-version3 --disable-w32threads --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmfx --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib"

  Did I miss a crucial one for GIF ?

  EDIT 27/06/2016

  Thanks to Gwen, I have a first output : I setted the context->pix_fmt to AV_PIX_FMT_BGR8. Btw I’m still facing some issues with the generated GIF. It’s not playing and encoding appears to fail.

  GIF generated in command lines with ffmpeg (left) . . . GIF generated programmatically (right)
  
  

  It looks like some options are not defined... also may be a wrong conversion between QImage and AVFrame ? I updated the code above. It represents a lot of code, so I tried to stay short. Don’t hesitate to ask more details.

  End of EDIT

  I’m not really familiar with ffmpeg, any kind of help would be highly appreciated. Thank you.

• Could NOT find FFmpeg (missing : swresample) (found version "56.1.0")

  28 juin 2016, par sushi

  I try to install obs (Open Broadcaster Software) in my Kali Linux 2.

  I follow this instruction. I have no problem until the obs building :

  cmake -DUNIX_STRUCTURE=1 -DCMAKE_INSTALL_PREFIX=/usr ..

  Where I get this error :

  Could NOT find FFmpeg (missing: swresample) (found version "56.1.0")

  I found this topic but I can’t use this command :

  apt-get -t jessie-backports install libswresample-dev

  Because I am on Kali Linux.

  This is the output of ffmpeg command :

  ffmpeg version N-79093-g7916f04 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.9.2 (Debian 4.9.2-10)
  
    configuration: --prefix=/root/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
  
    libavutil      55. 19.100 / 55. 19.100
  
    libavcodec     57. 28.103 / 57. 28.103
  
    libavformat    57. 28.102 / 57. 28.102
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 39.102 /  6. 39.102
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
  
  
  
  Use -h to get full help or, even better, run 'man ffmpeg'

• Cropping specific parts on a video using ffmpeg

  15 juin 2016, par Le Qs

  I have a video SB.ogv that i want to cut some parts.The video is 01:36 long and i want to cut out the first four seconds of the video.

  I a using this command

  ffmpeg -i SB.ogv -vcodec copy -acodec copy -ss 00:00:04 -to 00:01:36 outputFile.ogv

  I got this error

  qubit@qubit-HP-EliteBook-2540p:~/dv$ ffmpeg -i SB.ogv -vcodec copy -acodec copy -ss 00:00:04 -to 00:01:36 outputFile.ogv
  
  ffmpeg version 2.7.6-0ubuntu0.15.10.1 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 5.2.1 (Ubuntu 5.2.1-22ubuntu2) 20151010
  
    configuration: --prefix=/usr --extra-version=0ubuntu0.15.10.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --enable-shared --disable-stripping --enable-avresample --enable-avisynth --enable-frei0r --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-openal --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libxvid --enable-libzvbi --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-libssh --enable-libsoxr --enable-libx264 --enable-libopencv --enable-libx265
  
    libavutil      54. 27.100 / 54. 27.100
  
    libavcodec     56. 41.100 / 56. 41.100
  
    libavformat    56. 36.100 / 56. 36.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 16.101 /  5. 16.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.100 /  1.  2.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  [ogg @ 0x1bbfc80] Broken file, keyframe not correctly marked.
  
  Input #0, ogg, from 'SB.ogv':
  
    Duration: 00:01:36.40, start: 0.000000, bitrate: 1685 kb/s
  
      Stream #0:0: Data: none
  
      Stream #0:1: Video: theora, yuv420p, 1280x800 [SAR 1:1 DAR 8:5], 15 tbr, 15 tbn, 15 tbc
  
      Metadata:
  
        RECORDMYDESKTOP : 0.3.8.1
  
      Stream #0:2: Audio: vorbis, 22050 Hz, mono, fltp, 89 kb/s
  
  Output #0, ogg, to 'outputFile.ogv':
  
    Metadata:
  
      encoder         : Lavf56.36.100
  
      Stream #0:0: Video: theora, yuv420p, 1280x800 [SAR 1:1 DAR 8:5], q=2-31, 15 tbr, 15 tbn, 15 tbc
  
      Metadata:
  
        RECORDMYDESKTOP : 0.3.8.1
  
        encoder         : Lavf56.36.100
  
      Stream #0:1: Audio: vorbis, 22050 Hz, mono, 89 kb/s
  
      Metadata:
  
        encoder         : Lavf56.36.100
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (copy)
  
    Stream #0:2 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
  [ogg @ 0x1bbfc80] Broken file, keyframe not correctly marked.
  
      Last message repeated 13 times
  
  [ogg @ 0x1bbfc80] Broken file, non-keyframe not correctly marked.
  
      Last message repeated 9 times
  
  [ogg @ 0x1bbfc80] Broken file, keyframe not correctly marked.
  
      Last message repeated 2 times
  
  [ogg @ 0x1bbfc80] Broken file, non-keyframe not correctly marked.
  
      Last message repeated 8 times
  
  [ogg @ 0x1bbfc80] Broken file, keyframe not correctly marked.
  
  frame= 1090 fps=0.0 q=-1.0 Lsize=   19021kB time=00:01:32.00 bitrate=1693.7kbits/s    
  
  video:17509kB audio:1413kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.524658%
  
  qubit@qubit-HP-EliteBook-2540p:~/dv$ 

  The video SB.ogv is in the current directory.