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• HLS Streaming on IPad with IOS 7 / 8 causes 10 seconds freezed frame - no clue why

  25 juin 2014, par user3747636

  We have a problem with HLS h.264 mp4 on IPad devices using HLS streaming on IOS 7 and 8 :

  The first 9-15 seconds (the length of the first TS segment) only shows the first key frame (IDR) of the second TS segment, while the sound plays normally. When the second segment begins to play, the video continues as it should.

  HLS segmenter is a wowza with 10 seconds segment length. The encoding software we use is TMPG, latest version (uses x264). The funny thing is, that handbrake, xmedia recode, adobe me deliver videos which work. I am aware of the fact, that this hints to a bug within our encoding software, but if someone already had that problem with another software / segmenter combination and fixed it, I would like to know what the source of the problem was.

  What we already tried :

  • changing almost every setting so that it sticks as close as possible to apple’s recommendations
  • changing GOP structure, GOP length, encoding parameters which influence efficiency of encoding
  • analysis of the TS segments created by wowza, they are fine and begin all with keyframes
  • contact TMPG/Apple/Wowza support

  So, did anyone stumble upon this problem before ? Has anyone solved it ?

  EDIT :

  It seems that TMPGEnc uses a defective x264 implementation. The mediastreamvalidator tool from Apple returned an error stating that our TS segment "does not contain any IDR access unit with a SPS and a PPS" - which it does actually, but obviously in the wrong places if that somehow matters.

• How to convert large sequence of static gifs to video ?

  29 mars 2018, par Quinn

  I am trying to convert a large amount of static gifs(not animated) into video, but am completely lost on how to proceed.

  Specifications :

  QTY : 7,500 - 10,000 static .gif images

  File Size : 11kb ea.

  Image Dimensions : 580x580px

  File Naming : I_20000880002-20000880626.gif, I_20000880626-20000882042.gif, I_20000882042-20000891054.gif, etc...

  I have tried many different things, but none of them have worked. First, I tried Adobe Media Encoder. That failed, it couldn’t handle 10k files. I tried ffmpeg, which didn’t really work. The code I used is as follows :

  ffmpeg -r 60 -f image2 -s 580x580 -i pic%04d.png -vcodec libx264 -crf 25  -pix_fmt yuv420p test.mp4

  This didn’t work because it was trying to import .png files. I then changed the .png extension to .gif in the code. So :

  ffmpeg -r 60 -f image2 -s 580x580 -i pic%04d.gif -vcodec libx264 -crf 25  -pix_fmt yuv420p test.mp4

  I’m not an expert in ffmpeg by any means, so the code I executed might not have the proper syntax, at least in regards to -i pic%04d.gif. I suppose I could convert the .gifs into .pngs, then run the original code, but I’m not totally sure how to do that with ffmpeg.

  If anyone has any tips, they would be most appreciated. Also, I am using Windows 10 but I do have the linux subsystem installed. Thanks.

• Transcode H264 stream into mpeg2 with ffmpeg and nginx-rtmp module

  21 mai 2015, par inside

  I am using nginix web server and nginx-rtmp module for managing my video stream encoded in h264. Here is my nginx conf :

  rtmp {
  
  server {
  
      listen 1935;
  
  
  
      application big {
  
          live on;
  
  
  
      exec ffmpeg -re -i rtmp://localhost:1935/$app/$name -vcodec 
  
           libx264 -vprofile baseline -acodec libvo_aacenc -ac 1 -ar 441000 
  
           -f flv rtmp://localhost:1935/hls/${name};
  
        }
  
     }
  
  
  
     application hls
  
     {
  
        live on;
  
        hls_path /usr/local/nginx/html/video;
  
     }
  
  }

  it works well in browser, however because my mobile client is Adobe Air it would only work on Android but not Apple, because Apple doesn’t support H264 encoding through AIR applications, so I was trying to transcode the stream to something supported for example mpeg. And this is how I changed my ffmpeg :

      exec ffmpeg -re -i rtmp://localhost:1935/$app/$name -vcodec 
  
           mpeg2video -acodec copy -b:v 10M -b:a 128k 
  
           -f mpegts rtmp://localhost:1935/hls/${name};

  However it just won’t show the video not in a browser nor on device, my assumption is that it probably failed to transcode.

  Maybe I am missing something ? Any ideas are highly appreciated.
  Thank you.