问题:

I'd like to generate a video with a black or white background (or even nothing at all) that lasts for a specific duration (e.g. 2 hour long).

Can you please suggest a fast way to do it programatically (e.g. command line, OpenCV)? Thanks.

回答1:

You can use ffmpeg for this:

ffmpeg -t 7200 -s 640x480 -f rawvideo -pix_fmt rgb24 -r 25 -i /dev/zero empty.mpeg

UPDATE:

-t:       length of the video (in H:m:s format 00:00:00 or in seconds 0.000)
-s:       frame size
-f:       video format
-pix_fmt: pixel format
-r:       fps
-i:       input

回答2:

For an h264 output in a MP4 container, use:

ffmpeg -t 7200 -f lavfi -i color=c=black:s=640x480 -c:v libx264 -tune stillimage -pix_fmt yuv420p output.mp4

If you want to include an audio track, simply add the arguments for the audio input and encoding (if necessary). The output's duration will be determined by the shortest input, i.e. the audio. For example:

ffmpeg -f lavfi -i color=c=black:s=640x480 -i audio.ogg -c:v libx264 -tune stillimage -pix_fmt yuv420p -shortest -c:a aac -b:a 128k output-with-audio.mp4