Original address: https://www.cnblogs.com/gccbuaa/p/6800446.html
1. Add subtitles
命令：ffmpeg -i -filter_complex subtitles=filename=-y
Description: Use libass to embed subtitles for videos. Subtitles are hard subtitles directly embedded into the video.
Reference: http://ffmpeg.org/ffmpeg-filters.html#subtitles-1
2. Cut
命令：ffmpeg -i -ss 0 -t 10 -y
Note: ss follows the starting time, and t is the duration. The above command means to intercept 10 seconds starting from 0 seconds.
Reference: http://ffmpeg.org/ffmpeg.html
3. Zoom
Instruction: ffmpeg -i -filter_complex scale=320:240 -y
Description: The scale parameter is width and height.
4. Cutting
Instruction: ffmpeg -i -filter_complex crop=320:240:0:0 -y
Note: crop=320:240:0:0 is the cropping parameter. The detailed meaning is crop=width:height❌y, where width and height represent the size after cropping, and x:y represents the coordinates of the upper left corner of the cropping area.
5. Add watermark
命令：ffmpeg -i src.avi -vf “movie=[logo];[in][logo]overlay=100:100[out]”-y
Note: LogoName is the name of the picture, overlay=100:100 means overlay=x:y, and the watermark starts to be added at the (x, y) coordinates.
Upper left corner: overlay=10:10
Upper right corner: overlay=main_w-overlay_w-10:10
Bottom left corner: overlay=10:main_h-overlay_h-10
Bottom right corner: overlay=main_w-overlay_w-10:main_h-overlay_h-10
6. Splicing videos
The first command:
Step 1: ffmpeg -i INPUT -fmpeg OUTPUT
Step 2: copy /b INPUT+INPUT OUTPUT
Step 3: ffmpeg -i INPUT -f FORMAT OUTPUT
Description: The first step is to convert the input files into the same format, the second step is to use the copy command to merge the files, and the third step is to convert the merged files into the final video.
Example: Merge two videos named test.avi and test1_2.mp4 into resu.avi.
The first step: ffmpeg -itest1.avi test1.mpg
ffmpeg-i test1_2.mp4 test2.mpg
Step 2: copy /btest1.mpg+test2.mpg resu.mpge
Third step: ffmpeg -iresu.mpge -y resu.avi
Another command:
ffmpeg -i 1.mov -i 2.wmv -filter_complex “[0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]” -map [v] -map [a] output.mp4
7. Rotate
命令： ffmpeg -i -filter_complex transpose=X -y
Note: transpose=1 rotates 90° clockwise, transpose=2 rotates 90° counterclockwise.
8. Mirror
Mirror up and down
Order:
ffmpeg -i src.avi -vf “split[mian][tmp];[tmp]crop=iw:ih/2:0:0,vflip[flip];[mian][flip]overlay=0:H/2”-y GHO.avi
Note: It can be seen from the command that crop and vflip are on the same pipeline. Their processing flow is as shown in the following figure:
You can use this filter to flip upside down. The command is as follows: ffmpeg-i src.avi -vf “split [main][tmp]; [tmp] crop=iw:ih:0:0, vflip [flip];[main ][flip] overlay=0:0” The processing effect of GHO2.avi is the same as the command ffmpeg -isrc.avi -vf vflip GHO_v_1.avi. This is written just to better understand the filter processing chain.
Mirror left and right
命令： ffmpeg -i src.avi-vf “split [main][tmp]; [tmp] crop=iw/2:ih:0:0, hflip [flip]; [main][flip]overlay=W/2:0” GHO_H.avi
Note: The process is the same as the upper and lower mirroring, except that the coordinates are changed. And specify a filter named hfilp.
You can use this filter to reverse left and right. The command is as follows: ffmpeg-i src.avi -vf “split [main][tmp]; [tmp] crop=iw:ih:0:0, hflip [flip];[main ][flip] overlay=W:0” GHO_H_1.avi has the same effect as the command ffmpeg -i src.avi-vf hflip GHO_H_1.avi. This is written just to better understand the filter processing chain.
Summary: The split filter splits the input into 2 outputs . The crop filter selects the image range for flipping, the vflip and hflip filters flip the crop-cut image (vertically, horizontally), and the overlay filter specifies coordinates to paste the flipped image.
9. Add black borders
命令： ffmpeg -isrc.avi -vf pad=1280:800:0:40:black -y test_pad.avi
Description: pad=width:high❌y:coler. The width and height here refer to the resulting video size (including the size with black borders). XY refers to the source video added to the position of the result video, and coler is the fill color.
10. Adjust the volume
Command: ffmpeg -i -vol X
Description: No explanation
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