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• FFmpeg : building example C codes

  23 février 2021, par J. S.

  I have configured and compiled the FFmpeg library using this link :
https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

  



  Now, I am trying to build example C codes provided by FFmpeg from here :
https://github.com/FFmpeg/FFmpeg/tree/master/doc/examples

  



  However, when I run make install-examples or make install (suggested by /example/README), I receive this kind of message :

  



  


  make : *** No rule to make target '/doc/examples/README', needed by
 'install-examples'. Stop.

  


  



  I thought this may be due to the rules not being in the correct MakeFile format (I am not sure why they refers to README). How should I go about in fixing this and compiling the example codes ? I have tried to find solutions about this, but there doesn't seem to be much information online.

  



  Thank you.

  


• ffmpeg :how to apply animation in multiple images that will me merged in a video template in android

  1er mars 2023, par Pavan Ghanate

  I am trying to merge number of selected images from gallery to a video template in order to make video status or short video in a android app, I am able to merge the selected images in the video using below cammand now i want to add animation

  


   ArrayList<string> cmd2 = new ArrayList&lt;>();&#xA;    cmd2.add("-y");&#xA;    cmd2.add("-i");&#xA;    if (video_temp_path!= null){&#xA;        cmd2.add(video_temp_path);&#xA;    }else {&#xA;        cmd2.add(Environment.getExternalStorageDirectory().getPath()&#xA;                &#x2B; "/Download/happy.mp4");&#xA;    }&#xA;&#xA;&#xA;    for (int no = 0; no &lt; paths.length; no&#x2B;&#x2B;) {&#xA;        cmd2.add("-i");&#xA;&#xA;        cmd2.add(paths[no]);&#xA;&#xA;    }&#xA;&#xA;    cmd2.add("-filter_complex");&#xA;&#xA;&#xA;&#xA;    cmd2.add("[0][1]overlay=x=100:y=200:enable=&#x27;between(t,3,8)&#x27;[v1];" &#x2B;&#xA;            "[v1][2]overlay=x=100:y=200:enable=&#x27;between(t,10,15)&#x27;[v2];" &#x2B;&#xA;            "[v2][3]overlay=x=100:y=200:enable=&#x27;gt(t,17)&#x27;[v3]");&#xA;    cmd2.add("-map");&#xA;    cmd2.add("[v3]");&#xA;    cmd2.add("-map");&#xA;    cmd2.add( "0:a");&#xA;    cmd2.add(Environment.getExternalStorageDirectory().getPath()&#xA;            &#x2B; "/Download/output.mp4");&#xA;</string>

  


  but now i want to add fade in out animation to images so I am using this cammand generated by chatgpt but its giving me error

  


    ArrayList<string> cmd2 = new ArrayList&lt;>();&#xA;   cmd2.add("-y");&#xA;   cmd2.add("-i");&#xA;&#xA;   if (video_temp_path != null) {&#xA;    cmd2.add(video_temp_path);&#xA;  } else {&#xA;    cmd2.add(Environment.getExternalStorageDirectory().getPath() &#x2B;&#xA;            "/Download/happy.mp4");&#xA;}&#xA;&#xA;for (int no = 0; no &lt; paths.length; no&#x2B;&#x2B;) {&#xA;    cmd2.add("-loop");&#xA;    cmd2.add("1"); // loop the image&#xA;&#xA;    cmd2.add("-t");&#xA;    cmd2.add("5"); // duration of the image&#xA;&#xA;    cmd2.add("-i");&#xA;    cmd2.add(paths[no]);&#xA;&#xA;    cmd2.add("-filter_complex");&#xA;    cmd2.add("[1:v]fade=in:st=0:d=1[tin];" &#x2B;&#xA;            "[1:v]fade=out:st=4:d=1[tout];" &#x2B;&#xA;            "[0:v][tin]overlay=x=100:y=200" &#x2B;&#xA;            "[v1];" &#x2B;&#xA;            "[v1][tout]overlay=x=100:y=200:enable=&#x27;between(t,10,15)&#x27;[v2];" &#x2B;&#xA;            "[v2][2:v]overlay=x=100:y=200:enable=&#x27;gt(t,17)&#x27;[v3]");&#xA;&#xA;    cmd2.add("-map");&#xA;    cmd2.add("[v3]");&#xA;    cmd2.add("-map");&#xA;    cmd2.add("0:a");&#xA;}&#xA;&#xA;cmd2.add(Environment.getExternalStorageDirectory().getPath() &#x2B;&#xA;        "/Download/output.mp4");&#xA;</string>

  


  error is

  


   Option map (set input stream mapping) cannot be applied to input url /storage/emulated/0/Pictures/temp/1677570327312.jpg -- you are trying to apply an input option to an output file or vice versa. Move this option before the file it belongs to.


  


  2023-03-01 12:50:50.707 5950-6326/com.android.mergevideo E/mobile-ffmpeg : Error parsing options for input file /storage/emulated/0/Pictures/temp/1677570327312.jpg.
2023-03-01 12:50:50.707 5950-6326/com.android.mergevideo E/mobile-ffmpeg : Error opening input files :
2023-03-01 12:50:50.707 5950-6326/com.android.mergevideo E/mobile-ffmpeg : Invalid argument

  


• Video Keyframe and Iframe

  12 avril 2021, par SY Moon

  I have confused one thing for Video Frame extraction.

  


  I have sample.mp4 video, 15FPS.

  


  I tried extracting Keyframe with FFMPEG.

  


  ffmpeg -skip_frame nokey -i sample.mp4 -vsync 0 -frame_pts true out%d.png


  


  I get 29 Pictures and I believe I have got 29 I frames. (If I have wrong, Please correct me)

  


  Then I tried extracting specific timeline(10 sec) frame with picture

  


  ffmpeg -i sample.mp4 -ss 00:00:10 -frames:v 1 test1.png


  


  This output picture, I can not find same one among my Keyframes I get.

  


  Question : test1.png, What is frame type ? Does it one of P or B frame not I ?