FrameExtractor

the frame extractor for Video Datasets with GPU Acceleration, powered by Decord

• if you want to use GPU then you will need to install from the source, detail is follow the readme of Decord repository

My Environment Setting

• Decord == 0.4.2
• opencv-python == 4.4.0.44
• pillow-simd == 7.0.0.post3
• ffmpeg-python == 0.2.0

Usage

• first download the Video Dataset, for example an ActivityNet use a crawler or request and then you will get the follow structure

   v1-3 (ActivityNet version 1.3)
     L train
         L xxx.mp4
             .
             .
     L val
     L test

then you can run a script like below

• extract only frames (cpu version, just remove '--use-gpu' flag)

python frame_extractor.py --videos-path ./v1-3/ --frames-path ./frames/ --frame-size 240 --quality 0.7 --use-gpu

• extract only optical flows (only cpu)

python frame_extractor.py --videos-path ./v1-3/ --flows-path ./flows/ --frame-size 240 --quality 0.7 --flow-mode

• if you want get origin size of frames in video then adds '--origin-size' flag

i use the ffmpeg when using a cpu, do if you need consider of quality then check it below formula and table

ffmpeg_qscale = (1 - args_quality) * 30 + 1

args_quality = (31 - ffmpeg_qscale) / 30

args_quality	ffmpeg_qscale
1.0	1
0.9	4
0.8	7
0.7	10
0.6	13
0.5	16
0.4	19
0.3	22
0.2	25
0.1	28
0.05	29.5
0.0	31