To use FFmpeg to generate test videos and pictures, you need to install FFmpeg and use the command line tool to execute corresponding commands.
1. Generate a test video
Create a test video source file test.mp4:
ffmpeg -f lavfi -i testsrc=duration=5:size=1280x720:rate=30 test.mp4
The above command can generate a test video source file test.mp4 with a duration of 5 seconds, a resolution of 1280x720, and a frame rate of 30.
Compress and encode test.mp4 to generate output file output.mp4:
ffmpeg -i test.mp4 -c:v libx264 -crf 23 -preset fast -c:a copy output.mp4
The above command uses the H.264 encoder to compress and encode test.mp4 and output the file output.mp4. Among them, -crf 23 indicates that the compression quality factor is 23, and the smaller the value, the higher the compression quality; -preset fast indicates that the fast compression mode is used.
2. Generate test pictures
Use FFmpeg to generate a test picture test.jpg:
ffmpeg -f lavfi -i color=c=red:s=320x240:d=5 -pix_fmt rgb24 test.jpg
The above command uses FFmpeg to generate a test picture test.jpg with a resolution of 320x240, a red color, and a duration of 5 seconds.
Extract a frame at a certain point in time from a video as a picture:
ffmpeg -ss 00:00:05 -i input.mp4 -frames:v 1 -q:v 2 output.jpg
The above command extracts the video frame of the 5th second from the video file input.mp4, and uses a quality factor of 2 to generate the output image output.jpg. -ss specifies the time point to extract, -i specifies the input file, -frames:v specifies the number of frames to extract.