Regarding the extraction of I3D video features

[shinkyo0513]

Hi, Yazan,

Can I ask one question regarding the I3D video feature extraction? As I know, I3D produce one feature for a 16-frame clip. Do you use this setting to generate each feature, i.e., extracting one feature for continuous 16 frames? If so, assuming the index of the frame which I want to generate feature for is t, from which range should I sample the 16-frame clip, [t, t+15], or [t-15, t], or [t-7, t+8]...?

Thank you in advance!

[yabufarha]

Hi @shinkyo0513 , We used a window of size 21 around each frame, i.e. [t-10, t+10]. For more details about the features please check this repo https://github.com/ahsaniqbal/Kinetics-FeatureExtractor

[shinkyo0513]

Thank you!

By the way, how do you deal with the features for the frames at the beginning and end, i.e., frames in t=[0, 9] and in [T-9, T]? For these frames, there is no enough frames in their window size.

[yabufarha]

we applied zero padding for theses cases.

[yueyanpeng]

Hi I tried i3d feature extractor and got flow feature and rgb feature seperately, I was wondering in this project which feature is used? Thank you so much

[clearlove7-star]

Hi 你好 I tried i3d feature extractor and got flow feature and rgb feature seperately, I was wondering in this project which feature is used?我尝试了 i3d 特征提取器并分别获得了 flow 功能和 rgb 功能，我想知道在这个项目中使用了哪个功能？ Thank you so much非常感谢

May I ask if the two features you extracted are both 1024 dimensions