ResNet

The ResNet features are extracted at each frame of the provided video. The ResNet is pre-trained on the 1k ImageNet dataset. We extract features from the pre-classification layer. The implementation is based on the torchvision models. The extracted features are going to be of size num_frames x 2048. We additionally output timesteps in ms for each feature and fps of the video. We use the standard set of augmentations.

Set up the Environment for ResNet

Setup conda environment. Requirements are in file conda_env.yml

# it will create a new conda environment called 'video_features' on your machine
conda env create -f conda_env.yml

Quick Start

Activate the environment

conda activate video_features

and extract features at 1 fps from ./sample/v_GGSY1Qvo990.mp4 video and show the predicted classes

python main.py \
    feature_type=resnet \
    model_name=resnet101 \
    extraction_fps=1 \
    video_paths="[./sample/v_GGSY1Qvo990.mp4]" \
    show_pred=true

Supported Arguments

Argument	Default	Description
`model_name`	`resnet50`	A variant of ResNet. `resnet18` `resnet34` `resnet50` `resnet101` `resnet151` are supported.
`batch_size`	`1`	You may speed up extraction of features by increasing the batch size as much as your GPU permits.
`extraction_fps`	`null`	If specified (e.g. as `5`), the video will be re-encoded to the `extraction_fps` fps. Leave unspecified or `null` to skip re-encoding.
`device`	`"cuda:0"`	The device specification. It follows the PyTorch style. Use `"cuda:3"` for the 4th GPU on the machine or `"cpu"` for CPU-only.
`video_paths`	`null`	A list of videos for feature extraction. E.g. `"[./sample/v_ZNVhz7ctTq0.mp4, ./sample/v_GGSY1Qvo990.mp4]"` or just one path `"./sample/v_GGSY1Qvo990.mp4"`.
`file_with_video_paths`	`null`	A path to a text file with video paths (one path per line). Hint: given a folder `./dataset` with `.mp4` files one could use: `find ./dataset -name "*mp4" > ./video_paths.txt`.
`on_extraction`	`print`	If `print`, the features are printed to the terminal. If `save_numpy` or `save_pickle`, the features are saved to either `.npy` file or `.pkl`.
`output_path`	`"./output"`	A path to a folder for storing the extracted features (if `on_extraction` is either `save_numpy` or `save_pickle`).
`keep_tmp_files`	`false`	If `true`, the reencoded videos will be kept in `tmp_path`.
`tmp_path`	`"./tmp"`	A path to a folder for storing temporal files (e.g. reencoded videos).
`show_pred`	`false`	If `true`, the script will print the predictions of the model on a down-stream task. It is useful for debugging.

Examples

Start by activating the environment

conda activate video_features

It is pretty much the same procedure as with other features. The example is provided for the ResNet-50 flavour, but we also support ResNet-18,34,101,152. You can specify the model with the model_name parameter

python main.py \
    feature_type=resnet \
    model_name=resnet50 \
    device="cuda:0" \
    video_paths="[./sample/v_ZNVhz7ctTq0.mp4, ./sample/v_GGSY1Qvo990.mp4]"

If you would like to save the features, use --on_extraction save_numpy (or save_pickle) – by default, the features are saved in ./output/ or where --output_path specifies. In the case of frame-wise features, besides features, it also saves timestamps in ms and the original fps of the video into the same folder with features.

python main.py \
    feature_type=resnet \
    model_name=resnet50 \
    device="cuda:0" \
    on_extraction=save_numpy \
    file_with_video_paths=./sample/sample_video_paths.txt

Since these features are so fine-grained and light-weight we may increase the extraction speed with batching. Therefore, frame-wise features have --batch_size argument, which defaults to 1.

python main.py \
    feature_type=resnet \
    model_name=resnet50 \
    device="cuda:0" \
    batch_size=128 \
    video_paths="[./sample/v_ZNVhz7ctTq0.mp4, ./sample/v_GGSY1Qvo990.mp4]"

If you would like to extract features at a certain fps, add --extraction_fps argument

python main.py \
    feature_type=resnet \
    model_name=resnet50 \
    device="cuda:0" \
    extraction_fps=5 \
    video_paths="[./sample/v_ZNVhz7ctTq0.mp4, ./sample/v_GGSY1Qvo990.mp4]"

Credits

The TorchVision implementation.
The ResNet paper

License

The wrapping code is under MIT, yet, it utilizes torchvision library which is under BSD 3-Clause "New" or "Revised" License.