diff --git a/week08/lab/Readme.md b/week08/lab/Readme.md index 04e494b..a58e33c 100644 --- a/week08/lab/Readme.md +++ b/week08/lab/Readme.md @@ -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?