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• FFMpeg on Android not working

  30 août 2013, par user2171513

  I have build FFmpeg statically linked binary and I am using it to do some video/audio encoding -decoding in an Android application. If I use FFmpeg from my android application using

  Runtime.getRuntime().exec(Command);

  then it seems to suddenly crash in between without any error logs.
  but If I run the exact same command through adb shell then it succeeds. I am not able to figure out what would be the difference in running a native binary through adb shell or through an Android Application.

  Any help is appreciated.

• Concatenating/Splicing overlapping video clips with ffmpeg

  16 décembre 2020, par Jimbo1987

  I'm trying to concatenate multiple short .mp4 video clips from a security camera. The camera records short clips, with a few seconds on either end of a timespan when motion is detected. For example, two minutes of video will often be broken up into four 35 second clips, with the first/last few seconds of each clip being duplicative of the last/first few seconds of the previous/next clip.

  


  I simply concatenate the clips together using the ffmpeg concat demuxer, as described here : How to concatenate two MP4 files using FFmpeg ?, with

  


  (echo file 'first file.mp4' & echo file 'second file.mp4' )>list.txt
ffmpeg -safe 0 -f concat -i list.txt -c copy output.mp4


  


  Or else I transcode them into intermediate MPEG-2 transport streams, which I can then concatenate with the file-level concat protocol, as described here : https://trac.ffmpeg.org/wiki/Concatenate#protocol, with

  


  ffmpeg -i "first file.mp4" -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate1.ts
ffmpeg -i "second file.mp4" -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate2.ts
ffmpeg -i "concat:intermediate1.ts|intermediate2.ts" -c copy -bsf:a aac_adtstoasc output.mp4


  


  But either way, the resulting video (output.mp4) jumps backward in time a few seconds every half-minute or so because of the duplicated frames.

  


  I want to throw out the duplicate frames, and tie the clips together based on timestamps to achieve smooth playback of the concatenated full-length video. I'd strongly prefer to do this on Windows with ffmpeg if possible. Surely this has been done before, right ? Are there timestamps in the .mp4 files that I can use to determine how much overlap there is, and then splice at the proper point-in-time ? And if so, how do I read them, how do I splice at an exact point in time, and how do I get around the KeyFrames issue if I can splice at the exact point in time ?

  


• How to get a .bat file to process multiple videos ?

  29 avril 2019, par L J

  I’m simply trying to generate screen captures (every 2 seconds) from a large folder of videos. I already have code which works when I drag a single file onto it :

  "c:\program files\ffmpeg\bin\ffmpeg.exe" -i %1 -vf fps=fps=1.0/2.0 -qscale:v 2 "%~n1 - %%05d.jpg"
  
  pause

  But this doesn’t work when I drag multiple videos onto it.

  I have a poor understanding of ffmpeg scripting, so could anyone please give me the exact code to make this work ?