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I am using the following code to overlay my video on a background .png file:
ffmpeg -i C:\image.png -i C:\input.mp4 \
-filter_complex "[1:v][0:v]scale2ref=-1:950[ovrl][0v]; \
[0v][ovrl]overlay=x=(main_w-overlay_w)/2:y=0[watermark]" \
-map "[watermark]" -map 1:a -codec:v libx264 -preset veryfast \
-crf 18 -c:a copy C:\output.mp4
So, basically, my image.png is 1800x1200 and I am overlaying the video on top of this image starting from y=0 and the x coordinate to fall into the middle of the image.
However, since my input videos are of different resolution, of different sizes, that is why I am scaling the videos to fit exactly a height of 950 pixels and of a relative width.
Everything is working fine!
The question is: how can I optimize this process to get the same result but MUCH FASTER?
This is taking ages to process the videos one by one.
output
Marcel
Posted 2016-03-30T20:34:44.673
Reputation: 101
Please show the complete console output from your command. – llogan – 2016-03-30T21:15:29.270
Why are you using scale2ref with a fixed resolution? The whole idea of using scale2ref is that the reference is unknown or varying in size. For a fixed height of 950, you can just use regular scale and save some time. – Gyan – 2016-03-31T08:47:50.487
@Mulvya how? can you give an example? – Marcel – 2016-03-31T15:01:51.717
Replace with
"[1:v]scale=-1:950[ovrl];[0:v][ovrl]overlay=.....– Gyan – 2016-03-31T15:04:26.407@Mulvya your suggestion doesn't make the process faster, but it changes the scaling system. Mine rescaled everything to a a height of 950px and the width accordingly and leaving me the same margin of the background image. but yours, doesn't leave the same margins, the margins get reduced, I see less of the background image. – Marcel – 2016-03-31T15:13:21.580
That's because your image has ratio 3:2 and video 16:9. With scale2ref, the video is being distorted to 3:2. The regular scale filter preserves the video's original ratio. – Gyan – 2016-03-31T15:45:30.877
@Mulvya as i stated in the question, my image size and ratio is the same but the video size/codec/resolution/ratio is different from one video to another. I am trying to batch process everything (more than 10000 videos) so I need to find the fastest way to put this background image behind the videos, so as to center the video on the background image. – Marcel – 2016-03-31T16:20:49.820
What I'm saying is that using your present command (scale2ref) will distort videos whose ratio is different than the image. For speeding up, try
-profile:v baseline– Gyan – 2016-03-31T16:26:04.793@Mulvya so what will be the final version of the command be like according to your suggestion – Marcel – 2016-03-31T16:28:03.803
What I mentioned above. +
-profile:v baseline. Don't expect this to go much faster. – Gyan – 2016-03-31T17:05:45.390Please copy and paste the text instead of making images of text. You will probably see a speed increase using the
ultrafastpreset instead ofveryfast. – llogan – 2016-03-31T17:26:31.483