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• Android sws_scale RGB0 Frame taking long time and cause video latency [duplicate]

  17 avril 2018, par AJit

  This question already has an answer here :

  • Hardware scaling the OpenGL surface with NativeActivity
    
    1 answer
    

  Reading frames from FFMPEG and try to directly draw on a surface window in Native android, If scale the image to exact size what we are getting from the camera and apply YUV420P to RGBA it take 1ms to scale through av_image_fill_arrays but if scale image surface size, then It took 25 to 30ms to scale a same frame.

  Low latency :[ 1ms by sws_scale]

  swsContext = sws_getContext(videoCodecContext->width,
  
                                      videoCodecContext->height,
  
                                      videoCodecContext->pix_fmt,
  
                                      videoCodecContext->width,
  
                                      videoCodecContext->height,
  
                                      AV_PIX_FMT_RGB0,
  
                                      SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  av_image_fill_arrays()
  
  av_read_frame()
  
  avcodec_decode_video2(
  
  sws_scale(swsContext,
  
            (const uint8_t *const *) videoFrame->data,
  
            videoFrame->linesize,
  
            0,
  
            videoCodecContext->height,
  
            pictureFrame->data,
  
            pictureFrame->linesize);
  
  ANativeWindow_lock()
  
  Write all buffer bytes to window.
  
  ANativeWindow_unlockAndPost()

  Low latency :[ 30ms by sws_scale]

  [videoContext Width: 848 Height: 608]
  
  swsContext = sws_getContext(videoCodecContext->width,
  
                                      videoCodecContext->height,
  
                                      videoCodecContext->pix_fmt,
  
                                      1080,
  
                                      608,
  
                                      AV_PIX_FMT_RGB0,
  
                                      SWS_FAST_BILINEAR, NULL, NULL, NULL);

  NOTE : we are getting YUV420P pixel format.

  Whenever we change context width and height other than videoContext it will take more than 30ms so result is video delaying.

  TRY 1 : Pass the buffer from JNI to Java and create bitmap there to scale later on but createBitmap itself take ~500ms which is not good enough.

  TRY 2 : Direct YUV420P to RGB conversion, but still sws_scale is greater.

  TRY 3 : Direct writes YUV to window bites, but it shows without color (If anyone has a solution here will might helpful).

  TRY 4 : yuvlib, still not worth it.

  TRY 5 : Different pixel formats and flags in swsContext.

  

  Any help would appreciated.

• Overlay video onto another video at multiple points in time

  22 décembre 2024, par kbcool

  I have a case where I want to have a background video and use a second video overlaying the first but at multiple points in time. The second video is shorter.

  



  So for example the main video is a minute long and the second video is 10 seconds. I want to overlay the second video once at 15seconds then again at 35 seconds and then again at 55 seconds (terminating when the main video does).

  



  I am able to get the second video to overlay successfully using overlay filter and between option but it only ever works for the first overlay. The second overlay seems to show the last or first frame of the video(??) but for the period I set in between. I am guessing it needs to be rewound and played somehow.

  



  Eg :

  



  ffmpeg  -i background.mp4 -i overlay.mov -filter_complex "[0][1]overlay=0:0:enable='between(t,0,2)'[out];[out][1]overlay=-200:200:enable='between(t,4,8)'[out]" -map "[out]" -t 00:00:10 -y output.mp4


  



  I have also tried specifying the overlay as an input twice eg :

  



  ffmpeg  -i background.mp4 -i overlay.mov -i overlay.mov -filter_complex "[0][1]overlay=0:0:enable='between(t,0,2)'[out];[out][2]overlay=-200:200:enable='between(t,4,8)'[out]" -map "[out]" -t 00:00:10 -y output.mp4


  



  The same thing happens.

  



  I'm sure the answer is simple and probably to do with how I'm using inputs but I'm not able to wrap my head around how to get the overlay video to play twice at different times on top of the original.

  



  I have also tried using the setpts filter to rewind the overlay but again the results are exactly the same.

  



  Eg :

  



  ffmpeg  -i background.mp4 -i overlay.mov -filter_complex "[0][1]overlay=0:0:enable='between(t,0,2)'[out];[1]setpts=PTS-STARTPTS,[out]overlay=-200:200:enable='between(t,4,8)'[out]" -map "[out]" -t 00:00:10 -y output.mp4


  



  There are a lot of similar questions involving overlaying multiple videos but I can't find anything about reusing the same video at multiple points in time.

  


• how to create a video from images with different time interval ? [duplicate]

  30 mars 2018, par Imran

  This question already has an answer here :

  • FFMPEG - concat demuxer with duration filter issue
    
    1 answer
    
  • Using FFmpeg to join images with different timly distance
    
    2 answers
    

  I have set of image in local storage. ex : img000,img001,img002....img044
  I want, when img0014 then time interval 600millisecond and when imag030 then time interval 600millisecond and when imag044 then time interval 600millisecond
  When I Use This Commend then create video without time interval
  String[] cmd2="-r", "50", "-i", "/storage/emulated/0/Movies/pic/img%03d.jpg", "-c:v", "libx264", "-vf", "fps=25", "-pix_fmt", "yuv420p", video.mp4 ;

  please Help Me