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• How to convert a Video to a Slideshow with synced audio ? [closed]

  25 mai 2013, par Henry Mazza

  I want a simple way to convert a Ted Talk Presentation to a SlideShow + (synced)Audio format so I can listen to it in my car. I don't want to lose most of the visuals as it does in the audio format and also want to reduce the storage/cell data needs of the video format.

  So far I already extracted the key scenes with timing and the audio, now I must glue this together in a synced fashion.

  Possible ways I found but couldn't make work :

  • MP4Box to make a .m4b (audiobook/enhanced podcast) with mp4chap to set each image as a chapter image (but I could find proper documentation on how to do this)
  • FFMPEG to make a flat movie with the images (but I couldn't make each image stay for a random period of time)

  Ultimately I will automate this process in my VPS and make my private podcast server, so no fancy tools that don't work in Linux, please.

  EDIT : actually the Podcast is a lousy idea, the artwork must be in a square aspect ratio and has great compatibility problems with varius players. Still studing the Book format.

• ffmpeg API h264 encoded video does not play on all platforms

  19 juillet 2012, par TheSHEEEP

  Edit : In the previous version I used a very old ffmpeg API. I now use the newest libraries. The problem has only changed slightly, from "Main" to "High".

  I am using the ffmpeg C API to create a mp4 video in C++.

  I want the resulting video to be of the profile "Constrained Baseline", so that the resulting video can be played on as much platforms as possible, especially mobile, but I get "High" profile every time, even though I hard coded the codec profile to be FF_PROFILE_H264_CONSTRAINED_BASELINE. As a result, the video does not play on all our testing platforms.

  This is what "ffprobe video.mp4 -show_streams" tells about my video streams :

    Metadata:
  
  major_brand     : isom
  
  minor_version   : 512
  
  compatible_brands: isomiso2avc1mp41
  
  creation_time   : 1970-01-01 00:00:00
  
  encoder         : Lavf53.5.0
  
    Duration: 00:00:13.20, start: 0.000000, bitrate: 553 kb/s
  
  Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 320x180,
  
  424 kb/s, 15 fps, 15 tbr, 15 tbn, 30 tbc
  
  Metadata:
  
    creation_time   : 1970-01-01 00:00:00
  
    handler_name    : VideoHandler
  
  Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, s16, 12
  
  kb/s
  
  Metadata:
  
    creation_time   : 1970-01-01 00:00:00
  
    handler_name    : SoundHandler
  
  -------VIDEO STREAM--------
  
  [STREAM] 
  
  index=0
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  
  
  profile=High <-- This should be "Constrained Baseline"
  
  
  
  codec_type=video
  
  codec_time_base=1/30
  
  codec_tag_string=avc1
  
  codec_tag=0x31637661
  
  width=320
  
  height=180
  
  has_b_frames=0
  
  sample_aspect_ratio=N/A
  
  display_aspect_ratio=N/A
  
  pix_fmt=yuv420p
  
  level=30
  
  timecode=N/A
  
  is_avc=1
  
  nal_length_size=4
  
  id=N/A
  
  r_frame_rate=15/1
  
  avg_frame_rate=15/1
  
  time_base=1/15
  
  start_time=0.000000
  
  duration=13.200000
  
  bit_rate=424252
  
  nb_frames=198
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  TAG:creation_time=1970-01-01 00:00:00
  
  TAG:language=und
  
  TAG:handler_name=VideoHandler
  
  [/STREAM]
  
  -------AUDIO STREAM--------
  
  [STREAM]
  
  index=1
  
  codec_name=aac
  
  codec_long_name=Advanced Audio Coding
  
  profile=unknown
  
  codec_type=audio
  
  codec_time_base=1/44100
  
  codec_tag_string=mp4a
  
  codec_tag=0x6134706d
  
  sample_fmt=s16
  
  sample_rate=44100
  
  channels=2
  
  bits_per_sample=0
  
  id=N/A
  
  r_frame_rate=0/0
  
  avg_frame_rate=0/0
  
  time_base=1/44100
  
  start_time=0.000000
  
  duration=13.165714
  
  bit_rate=125301
  
  nb_frames=567
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  TAG:creation_time=1970-01-01 00:00:00
  
  TAG:language=und
  
  TAG:handler_name=SoundHandler
  
  [/STREAM]

  This is the function I use to add a video stream. All the values that come from ptr-> are defined from outside, do those values have to be specific values to get the correct profile ? :

  static AVStream *add_video_stream( Cffmpeg_dll * ptr, AVFormatContext *oc, enum   CodecID codec_id )
  
  {
  
  AVCodecContext *c;
  
  AVStream *st;  
  
  AVCodec* codec;
  
  
  
  // Get correct codec
  
  codec = avcodec_find_encoder(codec_id);
  
  if (!codec) {
  
      av_log(NULL, AV_LOG_ERROR, "%s","Video codec not found\n");
  
      exit(1);
  
  }
  
  
  
  // Create stream
  
  st = avformat_new_stream(oc, codec);
  
  if (!st) {
  
      av_log(NULL, AV_LOG_ERROR, "%s","Could not alloc stream\n");
  
      exit(1);
  
  }
  
  
  
  c = st->codec;
  
  
  
  /* Get default values */
  
  codec = avcodec_find_encoder(codec_id);
  
  if (!codec) {
  
      av_log(NULL, AV_LOG_ERROR, "%s","Video codec not found (default values)\n");
  
      exit(1);
  
  }
  
  avcodec_get_context_defaults3(c, codec);
  
  
  
  c->codec_id = codec_id;
  
  c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  c->bit_rate = ptr->video_bit_rate;
  
  av_log(NULL, AV_LOG_ERROR, " Bit rate: %i", c->bit_rate);
  
  
  
      c->qmin = ptr->qmin;
  
      c->qmax = ptr->qmax;
  
      c->me_method = ptr->me_method;
  
      c->me_subpel_quality = ptr->me_subpel_quality;
  
      c->i_quant_factor = ptr->i_quant_factor;
  
      c->qcompress = ptr->qcompress;
  
      c->max_qdiff = ptr->max_qdiff;
  
  
  
      // We need to set the level and profile to get videos that play (hopefully) on all platforms
  
      c->level = 30;
  
      c->profile = FF_PROFILE_H264_CONSTRAINED_BASELINE;
  
  
  
  c->width = ptr->dstWidth; 
  
  c->height = ptr->dstHeight; 
  
  
  
  c->time_base.den = ptr->fps;
  
  c->time_base.num = 1;
  
  c->gop_size = ptr->fps;
  
  c->pix_fmt = STREAM_PIX_FMT;
  
  c->max_b_frames = 0;
  
  
  
  // some formats want stream headers to be separate
  
  if(oc->oformat->flags & AVFMT_GLOBALHEADER)
  
      c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
  return st;
  
  }

  Additional info :

  As a reference video, I use the gizmo.mp4 that Mozilla serves as an example that plays on every platform/browser. It definitely has the "Constrained Baseline" profile, and definitely works on all our testing smartphones. You can download it here. Our self-created video doesn't work on all platforms and I'm convinced this is because of the profile.

  I am also using qt-faststart.exe to move the headers to the start of the file after creating the mp4, as this cannot be done in a good way in C++ directly. Could that be the problem ?

  Obviously, I am doing something wrong, but I don't know what it could be. I'd be thankful for every hint ;)

• Open .avi with OpenCV 2.4 & Ubuntu 11.04

  25 juin 2012, par CTZStef

  I try to open and read video files in .avi format using OpenCV. Here is my code :

  void MainWindow::on_actionOuvrir_fichier_triggered()
  
   140    +   {
  
   141    +    //mettre a -1 streamId
  
   142    +    streamId = -1;
  
   143    +    //ouvrir fenetre navigation fichiers pour recuperer path vers .avi
  
   144    +    QString fileName = QFileDialog::getOpenFileName(this,tr("Ouvrir fichier video"),"/home",
  
   145    +    tr("Videos (*.avi)"));
  
   146    +    std::string utf8_text = fileName.toUtf8().constData();
  
   147    +    //ouvrir .avi
  
   148    +    capture = new VideoCapture(utf8_text);
  
   149    +    //check ouverture
  
   150    +    if(!capture->isOpened())
  
   151    +    cout << "probleme ouverture fichier video" << endl;
  
   152    +    //calculer delay between each frame in ms
  
   153    +    rate = capture->get(CV_CAP_PROP_FPS);
  
   154    +    delay = 1000 / rate;
  
   155    +    //demarrer timer recordId
  
   156    +    recordId = startTimer(delay);
  
   157    +    //capture premiere frame
  
   158    +    if(!capture->read(in))
  
   159    +    cout << "probleme lecture frame fichier video" << endl;
  
   160    +   }

  I get no problem at compilation time, but I can't open a video file. While in debug mode I saw that string utf8_text had the good absolute path to my video, so obviously the problem comes from the constructor of the VideoCapture object. Then, I tried to install every codec pack I could or thought was relevant. But the problem is still there, capture->isOpened() still returns false, and in debug mode I can see that capture contains nothing.

  I am lost here, don't know what to try next. Any idea ??

  Thanks !!!

  [EDIT]
  Just in case, here is the output of ffmpeg -i myFile.avi

  faraday@faraday-Compaq-Evo-D510-e-pc:~/QtProjects/visionDev$ ffmpeg -i 1.avi
  
  FFmpeg version 0.6.6-4:0.6.6-0ubuntu0.11.04.1, Copyright (c) 2000-2010 the Libav developers
  
    built on Jun 12 2012 16:28:21 with gcc 4.5.2
  
    configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
  
    WARNING: library configuration mismatch
  
    libavutil   configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavcodec  configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavformat configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavdevice configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavfilter configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libswscale  configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libpostproc configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavutil     50.15. 1 / 50.15. 1
  
    libavcodec    52.72. 2 / 52.72. 2
  
    libavformat   52.64. 2 / 52.64. 2
  
    libavdevice   52. 2. 0 / 52. 2. 0
  
    libavfilter    1.19. 0 /  1.19. 0
  
    libswscale     0.11. 0 /  0.11. 0
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
  Input #0, avi, from '1.avi':
  
    Duration: 00:02:35.39, start: 0.000000, bitrate: 110595 kb/s
  
      Stream #0.0: Video: rawvideo, bgr24, 640x480, 15 tbr, 15 tbn, 15 tbc
  
  At least one output file must be specified

  I do not see anything wrong here, but I thought maybe someone will.

  I really need this to work soon, and right now it's a dead end...

  thanks

  [EDIT 2]

  I have just read this in the book OpenCV 2 Computer Vision Application Programming Cookbook by R. Laganiere :

  It is important to note that in order to open the specified video
  file, your computer must have the corresponding codec installed,
  otherwise cv::VideoCapture will not be able to understand the input
  file. Normally, if you are able to open your video file with a video
  player on your machine (such as the Windows Media Player), then OpenCV
  should also be able to read this file.

  Well, on my machine it is not that easy mister Laganiere... I hate this book.