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• FFmpeg : Remux f4v cutted from stream to mp4

  10 mai 2012, par Penthi

  I have a mp4 file cutted from a H.264/AAC stream with Wowza Media Server.
  After the cutting, the file was forced to mp4 format with the following command :

  ffmpeg -i wowza_output_file -vcodec copy -acodec copy -f mp4 -y wowza_output_file_copy

  From there I renamed it to test_f4v.mp4 and took ffprobe, to take a look at the file :

  ffprobe version 0.8, Copyright (c) 2007-2011 the FFmpeg developers
  
    built on Jul 20 2011 13:32:19 with gcc 4.4.3
  
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264
  
    libavutil    51.  9. 1 / 51.  9. 1
  
    libavcodec   53.  7. 0 / 53.  7. 0
  
    libavformat  53.  4. 0 / 53.  4. 0
  
    libavdevice  53.  1. 1 / 53.  1. 1
  
    libavfilter   2. 23. 0 /  2. 23. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test_f4v.mp4':
  
    Metadata:
  
      major_brand     : f4v 
  
      minor_version   : 0
  
      compatible_brands: isommp42m4v 
  
      creation_time   : 2012-04-23 12:36:06
  
    Duration: 01:00:01.84, start: 0.000000, bitrate: 2004 kb/s
  
      Stream #0.0(eng): Video: h264 (Baseline), yuv420p, 854x480 [PAR 1:1 DAR 427:240], 1903 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
  
      Metadata:
  
        creation_time   : 2012-04-23 12:36:06
  
      Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 96 kb/s
  
      Metadata:
  
        creation_time   : 2012-04-23 12:36:06

  Now there is a problem. I need a file, which has the following meta data :

  major_brand     : mp42
  
  compatible_brands: isom

  Is there a way to remux the mp4 file to get the major_brand and compatible_brands to the described values with ffmpeg ?

• Solving The XVD Puzzle

  15 avril 2012, par Multimedia Mike — General, multimedi archaeology, silicon valley, vg2, xvd, zygo

  I downloaded a multimedia file a long time ago (at least, I strongly suspected it was a multimedia file which is why I downloaded it). It went by the name of ‘lamborghini_850kbps.vg2′. I have had it in my collection for at least 7 years. I couldn’t remember where I found it. I downloaded it before it occurred to me to take notes about this sort of stuff.

  I found myself staring at the file again today and Googled the filename. This led me to a few Japanese sites which also contained working URLs for a few more .vg2 samples. Some other clues led me to a Russian language forum where someone had linked to a site that had Win32 codec modules that could process the files. The site was defunct but the Internet Archive Wayback Machine kept a copy for me, as well as copies of several more .vg2 samples from a defunct Japanese site previously involved with this codec.

  Sometimes this internet technology works really well. But I digress.

  Anyway, through all this, I finally found a clue : XVD. and wouldn’t you know, there is already a basic page on the MultimediaWiki describing the technology. In fact, while VG2 is a custom container, the MultimediaWiki states that the video component has a FourCC of VGMV, and there is already a file named VGMV.avi in the root V-codecs/ samples directory, something I vow to correct (that’s a big pet peeve of mine– putting samples in the root V-codecs/ or A-codecs/ directories).

  XVD… XVD… XVD… why does that sound so familiar ? Oh, of course ; there is a company named XVD and they have an office in the Bay Area which I have passed on numerous occasions, like this morning :

  
  <

  Someone originally connected with the multimedia technology in question operates a website which contains an unofficial history of the XVD tech. At first, I was wondering if the technology was completely defunct (and should therefore be open sourced). But if XVD’s solutions page (dated 2010) is to be believed, the technology is still in service, and purported to be better than H.264 and VC-1 : “The current generation of XVD video compression technology provides better video quality at any given data rate than standards-based codecs (H.264 or VC-1) with four times lower encoding complexity (when compared with H.264 Main Profile).”

  If they say so. For my part, I’m just happy that I have finally figured out what this lamborghini_850kbps.vg2 is so that I can properly catalog it on the samples site, which I have now done, along with other samples and various codecs modules.

  This episode reminds me that there’s a branch office of Zygo Corporation close to my home (though the headquarters are far, far away). The companies you see in Silicon Valley. Anyway, long-time open source multimedia hackers will no doubt recognize Zygo from the ZyGo FourCC & video codec transported in QuickTime files that was almost decode-able using an H.263 decoder.

  
  
  

  I may never learn what Zygo’s core competency actually is, but I will always remember their multimedia tech every time I run past their office.

• ffmpeg - Record Server Desktop Without Connection

  2 septembre 2015, par Chris.

  I set up an application which uses ffmpeg to record a desktop on an Amazon AWS EC2 instance having Windows Server 2012 R2 installed. It records the desktop and puts the result into a file.

  This works as long as a Remote Desktop or TeamViewer connection is active for that particular Amazon AWS EC2 instance. As soon as I close the Remote Desktop and TeamViewer connection the recording stops and continues as soon as I reconnect.

  I assume that it’s because the GPU doesn’t deliver frames without a display in use.

  How can I make sure that frames are constantly being rendered so that I can record them ?