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• How to get a loading return value

  5 septembre 2011, par anthonypliu

  I am trying to create a loading progress bar for my function :

  private string ConvertToFLV(string phyicalFilePath)
  
          {
  
              if (Path.GetExtension(phyicalFilePath).Equals(".flv")) return phyicalFilePath;
  
  
  
                  var argument = string.Format(@"-i ""{0}"" -vcodec flv -f flv -r 29.97 -s 320x240 -aspect 4:3 -b 300k -g 160 -cmp dct  -subcmp dct  -mbd 2 -flags +aic+cbp+mv0+mv4 -trellis 1 -ac 1 -ar 22050 -ab 56k ""{1}""", phyicalFilePath, Path.ChangeExtension(phyicalFilePath, "flv"));
  
                 // var argument = string.Format("-i {0} -crf 35.0 -vcodec libx264 -acodec libfaac -ar 48000 -ab 128k -coder 1 -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -me_method hex -subq 6 -me_range 16 -g 250 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -b_strategy 1 -threads 0 {1}", phyicalFilePath, Path.ChangeExtension(phyicalFilePath, "mp4"));
  
                  File.Delete(Path.ChangeExtension(phyicalFilePath, "flv"));
  
  
  
                  ProcessStartInfo process = new ProcessStartInfo(ffmpegPhysicalPath, argument);
  
                  Process proc = new Process();
  
                  proc.StartInfo = process;
  
                  proc.Start();
  
                  proc.WaitForExit();
  
  
  
                  return Path.ChangeExtension(phyicalFilePath, "flv");
  
  
  
  
  
  
  
          }

  Whent he command "proc.WaitForExit()" is invoked, I want to be able to return some type of load percentage. In the frontend I just have a gif loading image, but I want to be able to show progress on this, is there a way to do this ?

• Decode h264 video

  29 août 2011, par john bowring

  I am looking for a way to decode h264 (or indeed any video format) using c#. The ultimate goal is to be able to decode the images and very strictly control the playback in real time. The project I am working on is a non-linear video art piece where the HD footage is required to loop and edit itself on the fly, playing back certain frame ranges and then jumping to the next randomly selected frame range seamlessly.

  I have created an app which reads image files (jpegs) in from the disk and plays them on screen in order, I have total control over which frame is loaded and when it is displayed but at full HD res it takes slightly longer than I want to load the images from hard drive (which are about 500k each), I am thinking that using a compressed video format would be smaller and therefore faster to read and decode into a particular frame however I cannot find any readily available way to do this.

  Are there any libraries which can do this ? i.e. extract an arbitrary frame from a video file and serve it to my app in less time than it takes to show the frame (running at 25fps), I have looked into the vlc libraries and wrappers for ffmpeg but I don't know which would be better or if there would be another even better option. Also I don't know which codec would be the best choice as some are key frame based making arbitrary frame extraction probably very difficult.

  Any advice welcome, thanks

• FFMPEG : Videos converted from FLV to MP4 does not play in iPod but works in iPhone

  3 juin 2012, par Shakti Singh

  I used below command to convert videos from FLV,M4V to MP4.

  ffmpeg -y -i video_1336406262.flv -vcodec libx264 -vpre slow -vpre
  ipod640 -b 250k -bt 50k -acodec libfaac -ac 2 -ar 48000 -ab 64k -s
  480x320 video_1336406262.mp4

  The videos converted from M4V to MP4 are playing very well in both iPhone and iPod but the videos converted from FLV to MP4 does not work in iPod but does in iPhone.

  In the video area of HTML5 page iPod even does not show the play symbol.

  Could someone help here ?

  I am using the same command to convert from both FLV and M4V to MP4.

  Thanks