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• Video discoloration after upload using ffmpeg in Twitter API

  30 juin 2015, par Kamehameha

  What I’m trying to do is this -
  1) Take an image and audio, make it into a video using ffmpeg.(I am not well versed with ffmpeg but have a working command).
  This is the command that I am using right now -
  

  ffmpeg 
  
  -y 
  
  -loop 1 
  
  -i <image> 
  
  -i <sound> 
  
  -vcodec libx264 
  
  -vf 'scale=640:trunc(ow/a/2)*2' 
  
  -acodec aac 
  
  -strict experimental 
  
  -vb 1024k
  
  -minrate 1024k 
  
  -maxrate 1024k 
  
  -bufsize 1024k 
  
  -ar 44100 
  
  -shortest 
  
  
  
  </sound></image>

  2) Upload the video to Twitter, using it’s API - Uploading Chunked Media

  I am able to do both of these tasks.
  The problem :
  After converting to video, when I run it on vlc, it seems to be working fine(Original colors, valid audio).
  When I check the video in Twitter, it appears to be discolored.(though the audio is played properly)

  Here is an attached image of how it looks in vlc and how it looks after being uploaded -

  

  I think the ffmpeg command I am using is wrong.
  Has anyone faced similar issues after uploading to websites ?
  

  Kindly advise

• Unmapping memory-mapped images that are created during processing

  23 avril 2013, par user2309283

  I have a pretty big issue, although I only have the symptoms, and a theory on the cause.

  I have a C++ application under Windows 7x64 that uses system calls to FFMPEG 0.7.13 to extract frames from videos. When running, the parent application maintains a nice, predicable memory footprint in memory profilers (task manager, RAMMap) of about 2MB. I can see the individual calls to FFMPEG also come and go without incident. The trouble is, after about 100 calls to FFMPEG, and 70,000+ PNGs created (no one directory has more than 1500 pngs), the Windows memory page size raises gradually from about 2.5GB to over 7.0GB, and the system is brought to its knees. The sum of the processes for all users is no where near the reported Memory Page amount.

  I thought it might be Windows Search indexing related, so I turned off the indexing for the output directories in question using SetFileAttributes() and FILE_ATTRIBUTE_NOT_CONTENT_INDEXED, and while it seems to be working as advertised, it does not seem to combat the issue at hand. My current running theory is that all of these extracted PNGs are either fully or partially memory mapped, by FFMPEG or something else. I can also see the output PNGs under the RAMMap Physical Pages tab as standby mapped files.

  Question :
   Is there enough information here to possibly diagnose the exact problem ?
   Do I have a way to combat this issue ?

  Thanks in advance...

• ffmpeg library take long encoding time

  11 février 2019, par robinson george

  I am making an android app in which user can insert a images and its turned into a video. I tried making a video over the photos(selected by user) with replacing green colour in video using ffmpeg library. But the results are not very satisfying and it’s take around 4-5 seconds to encode a video of around 15 seconds. There are already many apps present in play store but i was wondering how they achieved this effect in so much lesser time(like < 1 sec to encode 15 sec video).
  For reference - https://play.google.com/store/apps/details?id=com.yy.biu
  https://play.google.com/store/apps/details?id=com.newbiz.mvmaster

  You can have a look at the result output file here- http://www.yourfilelink.com/get.php?fid=1881360