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• How to convert a single picture into video with some filters without losing performance ?

  11 avril 2019, par Zedd W

  I have a picture in jpeg format : cat.

  I converted this picture into a video through some ffmpeg filter : scale and zoompan. The video is that the picture is slowly enlarged

  Then, I encountered some problems when using the following command.

  command 1

  ffmpeg -loop 1 -i cat.jpeg -filter_complex "scale=iw*2:-1,zoompan=z='zoom+0.002':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':s=720x960" -pix_fmt yuv420p -vcodec libx264 -preset ultrafast -crf 28 -y -t 5 out.mp4

  command 2 (Just adjust the scale value of command 1)

  ffmpeg -loop 1 -i cat.jpeg -filter_complex "scale=iw*8:-1,zoompan=z='zoom+0.002':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':s=720x960" -pix_fmt yuv420p -vcodec libx264 -preset ultrafast -crf 28 -y -t 5 out.mp4

  Problems :

  1. The picture in the video will zoom in slowly, which is true, but until about the fourth second, the picture will return to the minimum and re-enlarge.Is this the filter parameter I used wrong ?

  2. There is a warning after running the command : [swscaler @ 0x113c66000] Warning: data is not aligned! This can lead to a speed loss. The picture size is 720 x 960 and the video is the same. 720/16 is an integer and 960/16 also an integer. So what not aligned ?

  3. There is another warning : deprecated pixel format used, make sure you did set range correctly. Did I set the pix_fmtparameter wrong ?

  4. command 2 and command 1 are different scale value, But the time they run will vary greatly (If you try to run it). Using a larger scale will have better results. So how to choose a scale value or have better way ?

• Sending multiple inputs over stdin to FFMPEG with Python

  23 novembre 2016, par Peter

  I have the following command that I can run from the terminal that will overlay an image and apply a zoom pan filter.

  ffmpeg -y -i image.jpeg -i overlay.png -pix_fmt yuv420p -filter_complex "[0:v]crop=out_w=in_w:out_h=in_w*0.562,scale=-2:3*ih,zoompan=z='min(zoom+0.0005,1.25)':d=75:x='iw/2-(iw/zoom/2)':y='ih/4-(ih/zoom/2)',overlay=0:0:enable='between(t,0,1)'[v]" -map "[v]" out.mp4

  I’m now attempting to run this command from Python 2.7 using the subprocess module. I’ve had success in the past using this method when ffmpeg expects 1 input, but now that it expects 2 inputs I’m a little stuck.

  from subprocess import Popen, PIPE
  
  
  
  filter = "[0:v]crop=out_w=in_w:out_h=in_w*0.562,scale=-2:3*ih,zoompan=z='min(zoom+0.0005,1.25)':d=75:x='iw/2-(iw/zoom/2)':y='ih/4-(ih/zoom/2)',overlay=0:0:enable='between(t,0,1)'[v]"
  
  img = open('image.jpeg')
  
  overlay = open('overlay'.png)
  
  
  
  video = Popen(['ffmpeg', '-f', 'image2pipe', '-y', '-i', '-', '-i', '-', '-pix_fmt', 'yuv420p',
  
            '-filter_complex', filter, '-map', "[v]" ,'out.mp4'],
  
            stdin=PIPE, stderr=PIPE)
  
  
  
  video.stdin.write(img.read())
  
  video.stdin.write(overlay.read())
  
  output, log = video.communicate()

  and the output I am getting :

  Input #0, image2pipe, from 'pipe:':
  
  Duration: N/A, bitrate: N/A
  
  Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 3597x5396 [SAR 300:300 DAR 3597:5396], 25 tbr, 25 tbn, 25 tbc
  
  pipe:: Invalid data found when processing input

• How to convert a single photo into video with some filters without losing performance ?

  11 avril 2019, par Zedd W

  I have a picture in jpeg format : cat.

  I converted this picture into a video through some ffmpeg filter : scale and zoompan. The video is that the picture is slowly enlarged

  Then, I encountered some problems when using the following command.

  command 1

  ffmpeg -loop 1 -i cat.jpeg -filter_complex "scale=iw*2:-1,zoompan=z='zoom+0.002':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':s=720x960" -pix_fmt yuv420p -vcodec libx264 -preset ultrafast -crf 28 -y -t 5 out.mp4

  command 2 (Just adjust the scale value of command 1)

  ffmpeg -loop 1 -i cat.jpeg -filter_complex "scale=iw*8:-1,zoompan=z='zoom+0.002':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':s=720x960" -pix_fmt yuv420p -vcodec libx264 -preset ultrafast -crf 28 -y -t 5 out.mp4

  Problems :

  1. The picture in the video will zoom in slowly, which is true, but until about the fourth second, the picture will return to the minimum and re-enlarge.Is this the filter parameter I used wrong ?

  2. There is a warning after running the command : [swscaler @ 0x113c66000] Warning: data is not aligned! This can lead to a speed loss. The picture size is 720 x 960 and the video is the same. 720/16 is an integer and 960/16 also an integer. So what not aligned ?

  3. There is another warning : deprecated pixel format used, make sure you did set range correctly. Did I set the pix_fmtparameter wrong ?

  4. command 2 and command 1 are different scale value, But the time they run will vary greatly (If you try to run it). Using a larger scale will have better results. So how to choose a scale value or have better way ?