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• Ffmpeg behaving intermittently

  10 mars 2024, par confused

  I'm noticing something weird, for the first time ever today, and I'm not sure what the problem could even possibly be.

  


  I first noticed it while stripping videos with a python script I wrote. Now I realize it is even happen with command line entry.

  


  Some, but not all videos, and some but not all segments within the same video are not stripping correctly. I'm taking numerous 1-2 hour long videos and cutting segments out of it. When I go to look at the video clip afterwards it automatically jumps to 2, 5, 8, 10 seconds into the video and starts playing there. It depends on the video segment as to how far ahead it skips. If I try to get it to go back and play the first part of the video it won't, it just jumps back to the 2-10 second jump ahead spot and plays from there. In further investigating it is stripping the audio off correctly and keep all the first 2-10 seconds of the audio with the video clip, but it is not picking up the first 2-10 seconds of the video. When I go into VLC Media Player and try to go back to the beginning I have a frozen image on the screen until I get to the 'predestined' 2-10 second mark, and then the video will play fine. When I watch the original video, it is okay but when I strip it the new video doesn't pick up the beginning of the video. Finally had to go to VLC media player to figure that part out as it was the only one who even let me play the underlying audio, every other media player wanted to jump ahead and skip the entire first 2-10 seconds altogether.

  


  This is happening with numerous different videos and video segments within the same video. Some segments it will strip fine others it won't.

  


  This occurs either way, python or command line. I just checked and the underlying video plays fine in the regular media player, until I strip the video, then it wants to skip the first 10 seconds.

  


  How might I fix this problem ?

  


• Android and ffmpeg. Play video (with sound)

  18 février 2014, par bukka.wh

  I have compiled ffmpeg library add it to my project and now I want to play video (with full list of options - stop, pause, forward, backward etc). I have read roman10 ffmpeg tutorial. And I also find out tutorial which describes how play video with ffmpeg and SDL framework. The difference (if I have correctly understood) is that in roman's tutorial each frame of video turns into a Bitmap and is then passed to Java code where it shows on SurfaceView. And in the second tutorial, the video is playing with the help of the SDL framework without passing it back to Java code.

  I want to ask some questions :

  1. Which way is better : return Bitmap back to Java and show it on SurfaceView or play it with SDL ?
  2. How can I play the sound of my video (can I do it with ffmpeg or do I need some additional libraries) ?

• FFMPEGH264Decoder - h264 video playing too fast

  25 février 2017, par Vineesh TP

  I am trying to play a .h264 video in iOS
  When loading the video the play back is too fast.

  I am reffering this source code

  Here is the code,

   CFFMPEGH264Decoder *decoder = new CFFMPEGH264Decoder(0);
  
      decoder->Init();
  
      decoder->Start();
  
      dispatch_queue_t decodeQueue = dispatch_queue_create("abc", NULL);
  
      dispatch_async(decodeQueue, ^{
  
          VideoPacket *vp = nil;
  
          while(true) {
  
              vp = [parser nextPacket];
  
              if(vp == nil) {
  
                  break;
  
              }
  
              decoder->Decode(vp.buffer, vp.size);
  
              unsigned char *result = decoder->GetResultData();
  
              if (result != 0) {
  
                //  NSLog(@"%d, %d",decoder->GetResultWidth(), decoder->GetResultHeight());
  
                  dispatch_async(dispatch_get_main_queue(), ^{
  
  
  
                    [glView displayYUV420pData:result width:decoder->GetResultWidth() height:decoder->GetResultHeight()];
  
                  });
  
  
  
                  decoder->ReleaseResultData();
  
              }
  
          }
  
      });

  When Encode the video I have to the frameRate is 24 only.
  But, after decode 5 second video play back is plying in 1 second.