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• How to scale and add correct a logo in ffmpeg command ?

  24 mars 2016, par Chris

  I am trying to apply a watermark and also to scale it to the current video size via ffmpeg command :

  Here is my inital comand that works without watermark

  ffmpeg -v 0 -vcodec h264_qsv -i 'udp://@some.ip:1234?fifo_size=1000000&overrun_nonfatal=1&buffer_size=1000000' -vf scale=iw:ih -profile baseline -acodec aac -ac 1 -ar 44100 -ab 64k -deinterlace -vcodec h264_qsv -bufsize 4000k -maxrate 3500k -preset veryfast -vb 2000k -f flv rtmp://127.0.0.1/app/720 

  Now I tried to add the picture as a watermark. There was a conflict while using with -vf scale=-1:ih*.5, in order to eliminate the problem I used -s 1280x720 to specify the resolution for the video stream, it worked but not properly.

  ffmpeg -v 0 -vcodec h264_qsv -i 'udp://@some.ip:1234?fifo_size=1000000&overrun_nonfatal=1&buffer_size=1000000' -i logo.png -filter_complex "overlay=10:10" -s 1280x720 -profile baseline -acodec aac -ac 1 -ar 44100 -ab 64k -deinterlace -vcodec h264_qsv -bufsize 4000k -maxrate 3500k -preset veryfast -vb 2000k -f flv rtmp://some.ip/app/720 

  The problem :

  How can I specify in the ffmpeg command the both sizes of video and logo(watermark) so they don’t conflict with each other and they auto adjust like -vf scale=-1:ih*.5 dose.

  Thank you !

• The duration of movie file recorded by AVAssetWriter is not correct

  1er mars 2016, par ideawu

  I am recording video files with AVAssetWriter combining with AVCaptureVideoDataOutputSampleBufferDelegate. So I can take control over every frame the camara gives in the method :

  - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
  
      double time = CMTimeGetSeconds(CMSampleBufferGetPresentationTimeStamp(sampleBuffer));
  
      NSLog(@"%f", time);
  
      [_videoInput appendSampleBuffer:sampleBuffer];
  
  }

  So I am so sure how many samples have been written to AVAssetWriter via AVAssetWriterInput, and I know exactly the start time and end time of the samples being written. The duration is calculated by end_time - start_time. Say the duration calculated in the video capture programm is 0.5 second.

  I get the .mov/.mp4 file on disk, inspected with ffmpeg -i, it shows a very different duration.

  ffmpeg -i m003.mp4 2>&1 | grep Dura
  
    Duration: 00:00:01.37, start: 0.836667, bitrate: 95 kb/s

  The movie file show a duration of 1.37 seconds, which it’s quite different with the EXACT duration 0.5.

  Does any one knows the reason ?

• fft : ppc : Place ff_fft_calc_interleave_altivec() under correct ifdefs

  30 janvier 2016, par Diego Biurrun

  fft : ppc : Place ff_fft_calc_interleave_altivec() under correct ifdefs
  Also fix #endif comments in the FFT init code.
  

  • [DBH] libavcodec/ppc/fft_altivec.S
  • [DBH] libavcodec/ppc/fft_init.c