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• movenc : Remove an outdated comment

  3 novembre 2014, par Martin Storsjö

  movenc : Remove an outdated comment
  QuickTime does support files with an empty initial movie
  
  these days.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/movenc.c

• Get MP3 content in C ? ffmpeg or mpg123lib ?

  20 novembre 2014, par Nicolás Múnera

  I’m trying for a personal project of mine to mix two mp3 files into one. I’ve been investigating for a couple of days how to read an mp3 with C and i’ve come up with two libraries, ffmpeg and mpg3lib, unfortunately the documentation is a little bit confusing.

  For now I’m trying to get the content of one MP3 file, I just want to understand which parts are valuable and which parts of the data I get are the ones i’m supposed to mix together. This is what i’ve got so far :

  int cont = 0;
  
  fprintf(stderr, "Starting decode...\n");
  
  while(1)
  
  {
  
           len = fread(buf, sizeof(unsigned char), INBUFF, in);
  
           if(len <= 0)
  
                   break;
  
           inc += len;
  
           ret = mpg123_feed(m, buf, len);
  
  
  
           while(ret != MPG123_ERR && ret != MPG123_NEED_MORE)
  
           {
  
                   ret = mpg123_decode_frame(m, &num, &audio, &bytes);
  
                   if(ret == MPG123_NEW_FORMAT)
  
                   {
  
                       mpg123_getformat(m, &rate, &channels, &enc);
  
                       initwavformat();
  
                       initwav();
  
                       fprintf(stderr, "New format: %li Hz, %i channels, encoding value %i\n", rate, channels, enc);
  
                   }
  
  
  
                   printf("Frame # %d: %s\n",cont,audio);          
  
                   fwrite(audio, sizeof(unsigned char), bytes, out);
  
                   outc += bytes;
  
           }
  
       if(ret == MPG123_ERR){
  
               fprintf(stderr, "Error: %s", mpg123_strerror(m));
  
               break; 
  
       }
  
   cont++;
  
   }

  With this code, I think i’m getting the content of the MP3, but when I print it I just get some weird characters, so I don’t know which strategy i should take.

  Could you guys give me a little bit of advice with this ?

  Thank you !

• opencv cvcapture avi = NULL

  3 janvier 2015, par ipunus

  I tried to solve the following problem for a lot of day :

  Target : I want to read a avi-file with xvid codec
  Status : cvcapturefromavi doesn’t work, give a NULL back
  Operating system MacOS Yosemite, Xcode 6 (clean system)

  First install opencv without ffmpeg support (downloaded,cmake and homebrew, tried both) Application crashed soon after starting, NULL for cvCaptureFromAVI

  Then I tried with ffmpeg, so installed separate ffmpeg -with xvid -with ffplay with homebrew and also opencv with ffmpeg support -> Application crashed soon after starting, Error opening file (/tmp/opencv-uG3i8H/opencv-2.4.9/modules/highgui/src/cap_ffmpeg_impl.hpp:545) -> NULL for cvCaptureFromAVI

  I can play the video-file with ffplay, no problem.

  Can you pls help ? I searched about two days in whole google...or in which codec I have to convert the file ?

  int main (int argc, const char* argv[])
  
  {
  
  CvCapture* video_in;
  
  IplImage* frame_video_in;
  
  video_in = cvCaptureFromAVI("video1.avi");
  
  
  
  cvNamedWindow("Original", CV_WINDOW_AUTOSIZE);  
  
  
  
  
  
  while (1) {
  
  
  
  
  
  frame_video_in = cvQueryFrame(video_in);
  
  
  
  
  
  cvShowImage("Original", frame_video_in);
  
  
  
  }
  
  
  
  cvDestroyAllWindows();
  
  return 0;
  
  }