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Correct ffmpeg CLI path typos for Lab 8 #18

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Correct ffmpeg CLI path typos for Lab 8 #18

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8 changes: 4 additions & 4 deletions week08/lab/Readme.md
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Expand Up @@ -28,22 +28,22 @@ If you get errors in the following steps, you can extract to data/ and change th

The first step is to extract a single image from the video.

`ffmpeg -i sherbrooke_video.avi -frames:v 1 data/ffmepg/test1/extracted.jpg`
`ffmpeg -i sherbrooke_video.avi -frames:v 1 data/ffmpeg/test1/extracted.jpg`
the option -frames:v specifies the number of frames to extract and data/ffmepg/test1/extracted.jpg is the output file.
When complete, browser your data directory from your workstation and open up data/ffmepg/test1/extracted.jpg and confirm that extract.


Now you wille extract 100 images from the file using the command `ffmpeg -i sherbrooke_video.avi -frames:v 100 data/ffmepg/test2/extract%04d.jpg`
Now you wille extract 100 images from the file using the command `ffmpeg -i sherbrooke_video.avi -frames:v 100 data/ffmpeg/test2/extract%04d.jpg`
With this command, %04d tells ffmpeg to name the extracted images with the serices with a 4 digit pattern, extract0001.jpg, extract0002.jpg, etc. Other numbers may be used, e.g. to use 2 numbers, the pattern would be %02d.


Review the images. How much did the scence change?
Now we'll adjust the frames per second used with the -r option, in this case with 1 frame per second.
`ffmpeg -i sherbrooke_video.avi -frames:v 100 -r 1 data/ffmepg/test2/extract%04d.jpg`
`ffmpeg -i sherbrooke_video.avi -frames:v 100 -r 1 data/ffmpeg/test2/extract%04d.jpg`


What's different? What happens if you change r?
Finally, we'll extract all the images with the command `ffmpeg -i sherbrooke_video.avi data/ffmepg/test3/extract%04d.jpg`
Finally, we'll extract all the images with the command `ffmpeg -i sherbrooke_video.avi data/ffmpeg/test3/extract%04d.jpg`


How long did it take?
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