Pyscenedetect - HOW Detect the middle keyframe ONLY - PLEASE HELP

[JeremyVN]

Hi guys,

On PySceneDetect, they said

"Print a table of detected scenes to the terminal, and save an image at the start, middle, and end frame of each scene:

scenedetect -i video.mp4 detect-content list-scenes -n save-images"

I just want to save only the middle frame of each scene. Do you guys know how to do it? Please help me with the code. Thank you in advance.

P/S: I have been making a montage image with start, middle, and end frame of each scene for summary and analyzing the news. There are more than 10000 keyframes embedded. I think it is so many. Start and end frame are quite useless. The file is too large and the size is quite unusual.

[JeremyVN]

" Usage Examples

Print table of detected scenes for video.mp4 and save to CSV file video-Scenes.csv:

scenedetect --input video.mp4 detect-content list-scenes

Same as above, but don’t create output file:

scenedetect --input video.mp4 detect-content list-scenes -n

save-images

The save-images command creates images for each detected scene. It saves a set number of images for each detected scene, always including the first and last frames.
Command Options

-o, --output DIR

Output directory to save images to. Overrides global option -o/–output if set.
-f, --filename NAME

Filename format, without extension, to use when saving image files. You can use the $VIDEO_NAME, $SCENE_NUMBER, $IMAGE_NUMBER, and $FRAME_NUMBER macros in the file name. Note that you may have to wrap the format in single quotes. [default: $VIDEO_NAME- Scene-$SCENE_NUMBER-$IMAGE_NUMBER]
-n, --num-images N

Number of images to generate. Will always include start/end frame, unless N = 1, in which case the image will be the frame at the mid-point in the scene. [default: 3]
-j, --jpeg

Set output format to JPEG (default).
-w, --webp

Set output format to WebP
-q, --quality Q

JPEG/WebP encoding quality, from 0-100 (higher indicates better quality). For WebP, 100 indicates lossless. [default: JPEG: 95, WebP: 100]
-p, --png

Set output format to PNG.
-c, --compression C

PNG compression rate, from 0-9. Higher values produce smaller files but result in longer compression time. This setting does not affect image quality, only file size. [default: 3]
-m, --frame-margin N

Number of frames to ignore at the beginning and end of scenes when saving images. [default: 3]
-s, --scale S

Optional factor by which saved images are rescaled. A scaling factor of 1 would not result in rescaling. A value <1 results in a smaller saved image, while a value >1 results in an image larger than the original. This value is ignored if either the height, -h, or width, -w, values are specified.
-h, --height H

Optional value for the height of the saved images. Specifying both the height and width, -w, will resize images to an exact size, regardless of aspect ratio. Specifying only height will rescale the image to that number of pixels in height while preserving the aspect ratio.
-w, --width W

Optional value for the width of the saved images. Specifying both the width and height, -h, will resize images to an exact size, regardless of aspect ratio. Specifying only width will rescale the image to that number of pixels wide while preserving the aspect ratio."

I tried to change -n = 1, --num-images N = 1, -N = 1, but none of them works. PLEASE HELP.