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• OpenCV videowriter H264 codec (ffmpeg)

  29 décembre 2014, par alcon

  I want to save a video with opencv with lossless compresion so I don’t lose any details of the frames. Everything works with the xvid codec but offcourse this is not a lossless compression so I found that the x264 codec is suitable. However it doesn’t work, I tried the following sample code but while running I get the following error : "could not find encoder for codec id 28 : encoder not found."

  cv::VideoWriter makeVideo;
  
  makeVideo.open("makevideo//newVideo.mp4", CV_FOURCC('X','2','6','4'), 30, cv::Size(1600,1200), true);
  
  cv::Mat image = imread("makevideo//frames//111.png");
  
  
  
  for(int i = 0; i < 200; i++)
  
      makeVideo << image;
  
  
  
  makeVideo.release();

  I found that for this to work, I need to have ffmpeg support. I’m currently using opencv2.4.6 and in this discussion (how can I use the openCV FFMPEG video I/O rather than the DirectShow one in Windows ?) someone mentioned that in opencv2.4 ffmpeg is automatically included. But its not working....

  Here (How to compile OpenCV 2.3 with ffmpeg support with Visual Studio 2010) I found how to compile opencv and ffmpeg yourself on windows. I followed all the steps sucessfully but still I get the same error....

• Create a demultiplexer for MPEG 2 TS in android

  17 novembre 2014, par anz

  I have a requirement where I need to extract ID3 tags from a MPEG2 TS(HLS STREAM). MPEG2 has a limited support in android in regards to playing the file. But my concern is to extract the ID3 tags(playing the file is not necessary). Hence I am not concerned with the codecs(encoding and decoding).

  I have explored the following options :

  libstagefright and OpenMax : A playback engine implemented by Google from Android 2.0.
  It has a MediaExtractor is responsible for retrieving track data and the corresponding meta data from the underlying file system or http stream. But according to this post Adding video codec to Android I need to build my own firmware or my own media player.I am hoping I don’t have to go down that path. More info on stagefright and openMax can be found here :

  An overview of Stagefright player

  Android’s Stagefright Media Player Architecture

  Custom Wrapper Codec Integration into Android

  How to integrate a decoder to multimedia framework

  Compiling and using FFMPEG : A complete, cross-platform solution to record, convert and stream audio and video. We can demultiplex ts files with this library as mentioned here :

  FFmpeg - Extracting video and audio from transport stream file (.ts).

  But I am not sure if I will be able to extract the ID3 tags from the HLS Stream. libavformat might be able to do this but I still need to come up with a mechanism for signaling the read metadata to my application.

  Compiling vlc for android : I have compiled vlc for android and made some modifications inside the transport module in demux component for extracting the tags, but it is not able to play all the streams that I am supplying to it.

  After looking through these options , I am still at a fix in how to achieve this. I don’t want to create a media player as I will not be playing the files nor do I want to build my own firmware. Using ffmpeg seems to be the most viable option, but I want to try this without using any third-party or open source library. My questions are :

  Is it even possible to create a demultiplexer from scratch that will work on android ?

  If possible then ,how to go about it ?

  Any options that I have missed ?

  I am new to this. Any help would be greatly appreciated..Thanks

• OpenCV won't open the same videofile as opened before

  12 novembre 2013, par OpenMinded

  I have a problem to load a videofile. I am using Visual Studio 2010 and OpenCV 2.4.6.

  Sometimes it loads video properly and sometimes it won't, although it is the same file and the same code (Nothing has changed). So basically, one day it works and the next day does not. I noticed some strange behavior BEFORE.

  When I run the code I get Unhandled exception

  ---

  

  ---

  and then No source available

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  ---

  A few weeks ago I wasn't able to open a video in one of my project. The problem was that if I opened a project from pinned Start menu than the video couldn't be loaded.

  

  BUT when I opened a solution right from a directory than video was loaded properly. I couldn't believe so I tried this more times.

  However, in either case it does not work this time.

  ALso, I tried to run Visual Studio as admin. Nothing.

  What could be a problem here ?