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• Compile FFMPEG for iOS development

  7 avril 2016, par Alec Gamble

  So I’ve been googling around and there seem to be a lot of answers to this questions... for people who know what they’re doing. Unfortunately I am not one of these people. I had a version of FFMPEG I was using in a project and now I want to port that project to iOS. So I have a version of FFMPEG with LAME installed on my desktop and in my C++ application I was just accessing this through the command line via the system() method. I also just downloaded the FFMPEG iOS build from here :

  https://github.com/kewlbear/FFmpeg-iOS-build-script

  and the gas-preprocessor from the link on that page but I’m unsure as to what to do with it now and how to get it to a state where I would be able to compile a basic FFMPEG test to my iPhone.

  ---

  I tried adding the libraries as mentioned in :
  How to Build FFMpeg as iOS Framework so my project hierarchy looks like :

  

  but when I do :

  #import <libavcodec></libavcodec>avcodec.h> as suggested

  or any other import I can think to do it always errors me out saying it can’t find it. I’m not sure if this is because I’m not using search paths correctly or my import line is wrong or what...

• How to change mp4 aspect ratio to 16:9 using ffmpeg ?

  1er mai 2016, par user1788736

  I got an mp4 video that I copy 4 minute of it using ffmpeg. After uploading to YouTube I noticed the uploaded video has black bars on both side of video(right and left side) !After searching for a way to remove those black bars I found that I need to use yt:stretch=16:9 !However,using yt:stretch=16.9 tag will not remove the black bars on iPhone and Samsung smart tv YouTube app !

  could an expert help me change the aspect ratio of original mp4 video to 16:9 using ffmpeg (without losing video quality) for re uploading to YouTube ? Thanks in advance ?

  I got two types of source with following information :

  1)Resolution:720x576 ,Frame rate:25 . Codec:H264 - MPEG-4 AVC(part 10)(avc1),
  
  2)Resolution:848x480 , Frame rate:24.804393,Codec:H264 - MPEG-4 AVC(part 10)(avc1)

  ffmpeg code used to trim the original video :

     ffmpeg -i orginalVideo.mp4 -ss 00:25:55 -t 00:04:02 -acodec copy -vcodec copy videoForYoutube.mp4

• concatenate mp4 videos with ffmpeg concat demuxer in android

  6 mai 2016, par Ara Badalyan

  I want to concatenate mp4 videos with ffmpeg, the problem is when I want to merge videos taken with Iphone and Android it throws problem

  " Non-monotonous DTS in output stream 0:1 ; previous : 150528, current : 139268 ; changing to 150529. This may result in incorrect timestamps in the output file."

  This is my code

  merge.txt

  file 'iphone.mp4'
  
  file 'android.mp4'

  ffmpeg command

  ffmpeg -f concat -i marge.txt -c copy -y merge.mp4

  If I can’t merge this videos how can i make them with same parameters (frame rate, bitrate...) and merge them ?

  P.S I use ffmpeg version 2.4.2 , because I can’t find android ffmpeg library higher then 2.4.2.