User tutorial: Classifying unlabeled videos¶

This section walks through how to classify videos using zamba. If you are new to zamba and just want to classify some videos as soon as possible, see the Quickstart guide.

This tutorial goes over the steps for using zamba if:

You already have zamba installed (for details see the Installation page)
You have unlabeled videos that you want to generate labels for
The possible class species labels for your videos are included in the list of possible zamba labels. If your species are not included in this list, you can retrain a model using your own labeled data and then run inference.

Basic usage: command line interface¶

Say that we want to classify the videos in a folder called example_vids as simply as possible using all of the default settings.

Minimum example for prediction in the command line:

$ zamba predict --data-dir example_vids/

Required arguments¶

To run zamba predict in the command line, you must specify --data-dir and/or --filepaths.

--data-dir PATH: Path to the folder containing your videos.
--filepaths PATH: Path to a CSV file with a column for the filepath to each video you want to classify. The CSV must have a column for filepath. Filepaths can be absolute or relative to the data directory.

All other flags are optional. To choose a model, either --model or --checkpoint must be specified. Use --model to specify one of the three pretrained models that ship with zamba. Use --checkpoint to run inference with a locally saved model. --model defaults to time_distributed.

Basic usage: Python package¶

Say that we want to classify the videos in a folder called example_vids as simply as possible using all of the default settings.

Minimum example for prediction using the Python package:

from zamba.models.model_manager import predict_model
from zamba.models.config import PredictConfig

predict_config = PredictConfig(data_dir="example_vids/")
predict_model(predict_config=predict_config)

The only two arguments that can be passed to predict_model are predict_config and (optionally) video_loader_config. The first step is to instantiate PredictConfig. Optionally, you can also specify video loading arguments by instantiating and passing in VideoLoaderConfig.

Required arguments¶

To run predict_model in Python, you must specify either data_dir or filepaths when PredictConfig is instantiated.

data_dir (DirectoryPath): Path to the folder containing your videos.
filepaths (FilePath): Path to a CSV file with a column for the filepath to each video you want to classify. The CSV must have a column for filepath. Filepaths can be absolute or relative to the data directory.

For detailed explanations of all possible configuration arguments, see All Optional Arguments.

Default behavior¶

By default, the time_distributed model will be used. zamba will output a .csv file with rows labeled by each video filename and columns for each class (ie. species). The default prediction will store all class probabilities, so that cell (i,j) can be interpreted as the probability that animal j is present in video i.

By default, predictions will be saved to zamba_predictions.csv in your working directory. You can save predictions to a custom directory using the --save-dir argument.

$ cat zamba_predictions.csv
filepath,aardvark,antelope_duiker,badger,bat,bird,blank,cattle,cheetah,chimpanzee_bonobo,civet_genet,elephant,equid,forest_buffalo,fox,giraffe,gorilla,hare_rabbit,hippopotamus,hog,human,hyena,large_flightless_bird,leopard,lion,mongoose,monkey_prosimian,pangolin,porcupine,reptile,rodent,small_cat,wild_dog_jackal
eleph.MP4,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
leopard.MP4,0.0,0.0,0.0,0.0,2e-05,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0125,0.0,0.0,0.0,0.0,0.0,0.0,0.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
blank.MP4,0.0,0.0,0.0,0.0,0.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
chimp.MP4,0.0,0.0,0.0,0.0,0.0,0.0,1e-05,0.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,1e-05,4e-05,0.00162,0.0,0.0,0.0,0.0,0.0,2e-05,2e-05,0.0,1e-05,0.0,0.0038,4e-05,0.0

The full prediction and video loading configuration for the process will also be saved out, in the same folder as the predictions under predict_configuration.yaml. To run the exact same inference process a second time, you can pass this YAML file to zamba predict per the Using YAML Configuration Files page:

$ zamba predict --config predict_configuration.yaml

Step-by-step tutorial¶

1. Specify the path to your videos¶

Save all of your videos within one folder.

They can be in nested subdirectories within the folder.
Your videos should be in be saved in formats that are suppored by FFmpeg, which are listed here. Any videos that fail a set of FFmpeg checks will be skipped during inference or training. By default, zamba will look for files with the following suffixes: .avi, .mp4, .asf. To use other video suffixes that are supported by FFmpeg, set your VIDEO_SUFFIXES environment variable.

Add the path to your video folder. For example, if your videos are in a folder called example_vids:

CLI

$ zamba predict --data-dir example_vids/

Python

predict_config = PredictConfig(data_dir='example_vids/')
predict_model(predict_config=predict_config)

2. Choose a model for prediction¶

If your camera videos contain species common to Central or West Africa, use either the time_distributed model or slowfast model model. slowfast is better for blank and small species detection. time_distributed performs better if you have many different species of interest, or are focused on duikers, chimpanzees, and/or gorillas.

If your videos contain species common to Europe, use the european model.

Add the model name to your command. The time_distributed model will be used if no model is specified. For example, if you want to use the slowfast model to classify the videos in example_vids:

CLI

$ zamba predict --data-dir example_vids/ --model slowfast

Python

predict_config = PredictConfig(
    data_dir='example_vids/', model_name='slowfast'
)
predict_model(predict_config=predict_config)

3. Choose the output format¶

There are three options for how to format predictions, listed from most information to least:

Store all probabilities (default): Return predictions with a row for each filename and a column for each class label, with probabilities between 0 and 1. Cell (i,j) is the probability that animal j is present in video i.
Presence/absence: Return predictions with a row for each filename and a column for each class label, with cells indicating either presence or absense based on a user-specified probability threshold. Cell (i, j) indicates whether animal j is present (1) or not present (0) in video i. The probability threshold cutoff is specified with --proba-threshold in the CLI.
Most likely class: Return predictions with a row for each filename and one column for the most likely class in each video. The most likely class can also be blank. To get the most likely class, add --output-class-names to your command. In Python, it can be specified by adding output_class_names=True when PredictConfig is instantiated. This is not recommended if you'd like to detect more than one species in each video.

Say we want to generate predictions for the videos in example_vids indicating which animals are present in each video based on a probability threshold of 50%:

CLI

$ zamba predict --data-dir example_vids/ --proba-threshold 0.5
$ cat zamba_predictions.csv
filepath,aardvark,antelope_duiker,badger,bat,bird,blank,cattle,cheetah,chimpanzee_bonobo,civet_genet,elephant,equid,forest_buffalo,fox,giraffe,gorilla,hare_rabbit,hippopotamus,hog,human,hyena,large_flightless_bird,leopard,lion,mongoose,monkey_prosimian,pangolin,porcupine,reptile,rodent,small_cat,wild_dog_jackal
eleph.MP4,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
leopard.MP4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0
blank.MP4,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
chimp.MP4,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Python

predict_config = PredictConfig(
    data_dir="example_vids/", proba_threshold=0.5
)
predict_model(predict_config=predict_config)
predictions = pd.read_csv("zamba_predictions.csv")
predictions

filepath	blank	chimpanzee_bonobo	elephant	leopard
blank.MP4	1	0	0	0
chimp.MP4	0	1	0	0
eleph.MP4	0	0	1	0
leopard.MP4	0	0	0	1

4. Specify any additional parameters¶

And there's so much more! You can also do things like specify your region for faster model download (--weight-download-region), use a saved model checkpoint (--checkpoint), or specify a different folder where your predictions should be saved (--save-dir). To read about a few common considerations, see the Guide to Common Optional Parameters page.

5. Test your configuration with a dry run¶

Before kicking off a full run of inference, we recommend testing your code with a "dry run". This will run one batch of inference to quickly detect any bugs. See the Debugging page for details.