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• ffmpeg not working from php script but works from command line [on hold]

  12 février 2015, par david perlman

  i can run youtube-dl.php from command line "php youtube-dl.php" works fine

  but not working from http...
  is it someting with chown ?

  $url = "https://www.youtube.com/watch?v=KdS6HFQ_LUc";
  
  
  
  echo "Saving $url";
  
  
  
  
  
  $cmd = 'youtube-dl -o "/var/www/domain.com/test/%(title)s.%(ext)s" '.$url.' -f bestvideo+bestaudio'; 
  
  exec($cmd, $output, $ret);
  
  echo 'output: ';
  
  var_export($output);

  echo "\nret : " ;
  var_export($ret) ;

• FFMPEG reports invalid video resolution, video headers container seem to be different from actual frames !

  20 décembre 2011, par Emiliano

  Quick question, i have a movie, which was cut and rendered with Sony Vegas from its original format to a .wmv file. Here comes the tricky part, movie when played, either with VLC or WMP, has a resolution of 656x480 ... BUT when i run a ffmpeg -i on it, it says it has a resolution of 600x480 ....

  I took the time of actually capturing a frame and croping it with photoshop and its 656 and not 600 like ffmpeg its reporting, why would this could be happening ? How could i fix the headers resolution ? Would that have any impact on video re-rendering ? As i said, VLC and WMP seems not to care about the incorrect headers and are playing it right, BUT, jwplayer seems to be using the header information, which i don't blame him, its correct to do that, but why the video headers could be wrong ?

  ffmpeg -i trailer.wmv

  Input #0, asf, from 'trailer.wmv' :
  Duration : 00:01:04.93, start : 3.000000, bitrate : 2144 kb/s
  Stream #0.0 : Audio : wmav2, 44100 Hz, mono, 32 kb/s
  Stream #0.1 : Video : wmv3, yuv420p, 600x480 [PAR 59:54 DAR 295:216], 2065 kb/
  s, 25.00 tb(r)

  And yeah, the PAR/DAR parameters are also wrong, but honestly, i don't understand that technical shit, usually watch video and make sure it look good, any feedback would be appreciated :P

  Is there a way to change the container information with ffmpeg so applications that actually do use the container information don't render video incorrectly ?

• Webcam stream with FFMpeg on iPhone

  6 décembre 2011, par Saphrosit

  I'm trying to send and show a webcam stream from a linux server to an iPhone app. I don't know if it's the best solution, but I downloaded and installed FFMpeg on the linux server (following, for those who want to know, this tutorial).
  FFMpeg is working fine. After a lots of wandering, I managed to send a stream to the client launching

  ffmpeg  -s 320x240 -f video4linux2 -i /dev/video0 -f mpegts -vcodec libx264 udp://192.168.1.34:1234

  where 192.168.1.34 is the address of the client. Actually the client is a Mac, but it is supposed to be an iPhone. I know the stream is sent and received correctly (tested in different ways).
  However I didn't managed to watch the stream directly on the iPhone.
  I thought of different (possible) solutions :

  • first solution : store incoming data in a NSMutableData object. Then, when the stream ends, store it and then play it using a MPMoviePlayerController. Here's the code :

    [video writeToFile:@"videoStream.m4v" atomically:YES];
    
    NSURL *url = [NSURL fileURLWithPath:@"videoStream.m4v"];
    
    
    
    MPMoviePlayerController *videoController = [[MPMoviePlayerController alloc] initWithContentURL:url];
    
    
    
    [videoController.view setFrame:CGRectMake(100, 100, 150, 150)];
    
    
    
    [self.view addSubview:videoController.view];
    
    
    
    [videoController play];

    the problem of this solution is that nothing is played (I only see a black square), even if the video is saved correctly (I can play it directly from my disk using VLC). Besides, it's not such a great idea. It's just to make things work.

  • Second solution : use CMSampleBufferRef to store the incoming video. Much more problems comes with this solution : first of all, there's no CoreMedia.framework in my system. Besides I do not get well what does this class represents and what should I do to make it works : I mean if I start (somehow) filling this "SampleBuffer" with bytes I receive from UDP connection, then it will automatically call the CMSampleBufferMakeDataReadyCallback function I set during creation ? If yes, when ? When the single frame is completed or when the whole stream is received ?

  • Third solution : use AVFoundation framework (neither this is actually available on my Mac). I did not understand if it's actually possible to start recording from a remote source or even from a NSMutableData, a char* or something like that. On AVFoundation Programming Guide I didn't find any reference that say if it's possible or not.

  I don't know which one of this solution is the best for my purpose. ANY suggestion would be appreciate.

  Besides, there's also another problem : I didn't use any segmenter program to send the video. Now, if I'm not getting wrong, segmenter needs to split the source video in smaller/shorter video easier to send. If it is right, then maybe it's not strictly necessary to make things work (may be added later). However, since the server is running under linux, I cannot use Apple's mediastreamsegmeter. May someone suggest an opensource segmenter to use in association with FFMpeg ?

  ---

  UPDATE : I edited my question adding more informations on what I did since now and what my doubts are.