MediaPipe-rs

A Rust library for MediaPipe tasks for WasmEdge WASI-NN

Introduction

• Easy to use: low-code APIs such as mediapipe-python.
• Low overhead: No unnecessary data copy, allocation, and free during the processing.
• Flexible: Users can use custom media bytes as input.
• For TfLite models, the library not only supports all models downloaded from MediaPipe Solutions but also supports TF Hub models and custom models with essential information.

Status

• Object Detection
• Image Classification
• Image Segmentation
• Interactive Image Segmentation
• Gesture Recognition
• Hand Landmark Detection
• Image Embedding
• Face Detection
• Face Landmark Detection
• Pose Landmark Detection
• Audio Classification
• Text Classification
• Text Embedding
• Language Detection

Task APIs

Every task has three types: XxxBuilder, Xxx, XxxSession. (Xxx is the task name)

• XxxBuilder is used to create a task instance Xxx, which has many options to set.

  example: use ImageClassifierBuilder to build a ImageClassifier task.

  let classifier = ImageClassifierBuilder::new()
        .max_results(3) // set max result
        .category_deny_list(vec!["denied label".into()]) // set deny list
        .gpu() // set running device
        .build_from_file(model_path)?; // create a image classifier
  

• Xxx is a task instance, which contains task information and model information.

  example: use ImageClassifier to create a new ImageClassifierSession

  let classifier_session = classifier.new_session()?;
  

• XxxSession is a running session to perform pre-process, inference, and post-process, which has buffers to store mid-results.

  example: use ImageClassifierSession to run the image classification task and return classification results:

  let classification_result = classifier_session.classify(&image::open(img_path)?)?;
  

  Note: the session can be reused to speed up, if the code just uses the session once, it can use the task's wrapper function to simplify.

  // let classifier_session = classifier.new_session()?;
  // let classification_result = classifier_session.classify(&image::open(img_path)?)?;
  // The above 2-line code is equal to: 
  let classification_result = classifier.classify(&image::open(img_path)?)?;
  

Available tasks

• vision:
  • gesture recognition: GestureRecognizerBuilder -> GestureRecognizer -> GestureRecognizerSession
  • hand detection: HandDetectorBuilder -> HandDetector -> HandDetectorSession
  • image classification: ImageClassifierBuilder -> ImageClassifier -> ImageClassifierSession
  • image embedding: ImageEmbedderBuilder -> ImageEmbedder -> ImageEmbedderSession
  • image segmentation: ImageSegmenterBuilder -> ImageSegmenter -> ImageSegmenterSession
  • object detection: ObjectDetectorBuilder -> ObjectDetector -> ObjectDetectorSession
• audio:
  • audio classification: AudioClassifierBuilder -> AudioClassifier -> AudioClassifierSession
• text:
  • text classification: TextClassifierBuilder -> TextClassifier -> TextClassifierSession

Examples

Image classification

use mediapipe_rs::tasks::vision::ImageClassifierBuilder;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (model_path, img_path) = parse_args()?;

    let classification_result = ImageClassifierBuilder::new()
        .max_results(3) // set max result
        .build_from_file(model_path)? // create a image classifier
        .classify(&image::open(img_path)?)?; // do inference and generate results

    // show formatted result message
    println!("{}", classification_result);

    Ok(())
}

Example input: (The image is downloaded from https://storage.googleapis.com/mediapipe-assets/burger.jpg)

Example output in console:

$ cargo run --release --example image_classification -- ./assets/models/image_classification/efficientnet_lite0_fp32.tflite ./assets/testdata/img/burger.jpg
    Finished release [optimized] target(s) in 0.01s
     Running `/mediapipe-rs/./scripts/wasmedge-runner.sh target/wasm32-wasi/release/examples/image_classification.wasm ./assets/models/image_classification/efficientnet_lite0_fp32.tflite ./assets/testdata/img/burger.jpg`
ClassificationResult:
  Classification #0:
    Category #0:
      Category name: "cheeseburger"
      Display name:  None
      Score:         0.70625573
      Index:         933

Object Detection

use mediapipe_rs::postprocess::utils::draw_detection;
use mediapipe_rs::tasks::vision::ObjectDetectorBuilder;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (model_path, img_path, output_path) = parse_args()?;

    let mut input_img = image::open(img_path)?;
    let detection_result = ObjectDetectorBuilder::new()
        .max_results(2) // set max result
        .build_from_file(model_path)? // create a object detector
        .detect(&input_img)?; // do inference and generate results

    // show formatted result message
    println!("{}", detection_result);

    if let Some(output_path) = output_path {
        // draw detection result to image
        draw_detection(&mut input_img, &detection_result);
        // save output image
        input_img.save(output_path)?;
    }

    Ok(())
}

Example input: (The image is downloaded from https://storage.googleapis.com/mediapipe-tasks/object_detector/cat_and_dog.jpg)

Example output in console:

$ cargo run --release --example object_detection -- ./assets/models/object_detection/efficientdet_lite0_fp32.tflite ./assets/testdata/img/cat_and_dog.jpg
    Finished release [optimized] target(s) in 0.00s
     Running `/mediapipe-rs/./scripts/wasmedge-runner.sh target/wasm32-wasi/release/examples/object_detection.wasm ./assets/models/object_detection/efficientdet_lite0_fp32.tflite ./assets/testdata/img/cat_and_dog.jpg`
DetectionResult:
  Detection #0:
    Box: (left: 0.12283102, top: 0.38476586, right: 0.51069236, bottom: 0.851197)
    Category #0:
      Category name: "cat"
      Display name:  None
      Score:         0.8460574
      Index:         16
  Detection #1:
    Box: (left: 0.47926134, top: 0.06873521, right: 0.8711677, bottom: 0.87927735)
    Category #0:
      Category name: "dog"
      Display name:  None
      Score:         0.8375256
      Index:         17

Example output:

Text Classification

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let model_path = parse_args()?;

    let text_classifier = TextClassifierBuilder::new()
        .max_results(1) // set max result
        .build_from_file(model_path)?; // create a text classifier

    let positive_str = "I love coding so much!";
    let negative_str = "I don't like raining.";

    // classify show formatted result message
    let result = text_classifier.classify(&positive_str)?;
    println!("`{}` -- {}", positive_str, result);

    let result = text_classifier.classify(&negative_str)?;
    println!("`{}` -- {}", negative_str, result);

    Ok(())
}

Example output in console (use the bert model):

$ cargo run --release --example text_classification -- ./assets/models/text_classification/bert_text_classifier.tflite
    Finished release [optimized] target(s) in 0.01s
     Running `/mediapipe-rs/./scripts/wasmedge-runner.sh target/wasm32-wasi/release/examples/text_classification.wasm ./assets/models/text_classification/bert_text_classifier.tflite`
`I love coding so much!` -- ClassificationResult:
  Classification #0:
    Category #0:
      Category name: "positive"
      Display name:  None
      Score:         0.99990463
      Index:         1

`I don't like raining.` -- ClassificationResult:
  Classification #0:
    Category #0:
      Category name: "negative"
      Display name:  None
      Score:         0.99541473
      Index:         0

Gesture Recognition

use mediapipe_rs::tasks::vision::GestureRecognizerBuilder;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (model_path, img_path) = parse_args()?;

    let gesture_recognition_results = GestureRecognizerBuilder::new()
        .num_hands(1) // set only recognition one hand
        .max_results(1) // set max result
        .build_from_file(model_path)? // create a task instance
        .recognize(&image::open(img_path)?)?; // do inference and generate results

    for g in gesture_recognition_results {
        println!("{}", g.gestures.classifications[0].categories[0]);
    }

    Ok(())
}

Example input: (The image is download from https://storage.googleapis.com/mediapipe-tasks/gesture_recognizer/victory.jpg)

Example output in console:

$ cargo run --release --example gesture_recognition -- ./assets/models/gesture_recognition/gesture_recognizer.task ./assets/testdata/img/gesture_recognition_google_samples/victory.jpg
    Finished release [optimized] target(s) in 0.02s
     Running `/mediapipe-rs/./scripts/wasmedge-runner.sh target/wasm32-wasi/release/examples/gesture_recognition.wasm ./assets/models/gesture_recognition/gesture_recognizer.task ./assets/testdata/img/gesture_recognition_google_samples/victory.jpg`
      Category name: "Victory"
      Display name:  None
      Score:         0.9322255
      Index:         6

Audio Input

Every audio media which implements the trait AudioData can be used as audio tasks input. Now the library has builtin implementation to support symphonia, ffmpeg, and raw audio data as input.

Examples for Audio Classification:

use mediapipe_rs::tasks::audio::AudioClassifierBuilder;

#[cfg(feature = "ffmpeg")]
use mediapipe_rs::preprocess::audio::FFMpegAudioData;
#[cfg(not(feature = "ffmpeg"))]
use mediapipe_rs::preprocess::audio::SymphoniaAudioData;

#[cfg(not(feature = "ffmpeg"))]
fn read_audio_using_symphonia(audio_path: String) -> SymphoniaAudioData {
    let file = std::fs::File::open(audio_path).unwrap();
    let probed = symphonia::default::get_probe()
        .format(
            &Default::default(),
            symphonia::core::io::MediaSourceStream::new(Box::new(file), Default::default()),
            &Default::default(),
            &Default::default(),
        )
        .unwrap();
    let codec_params = &probed.format.default_track().unwrap().codec_params;
    let decoder = symphonia::default::get_codecs()
        .make(codec_params, &Default::default())
        .unwrap();
    SymphoniaAudioData::new(probed.format, decoder)
}

#[cfg(feature = "ffmpeg")]
fn read_video_using_ffmpeg(audio_path: String) -> FFMpegAudioData {
    ffmpeg_next::init().unwrap();
    FFMpegAudioData::new(ffmpeg_next::format::input(&audio_path.as_str()).unwrap()).unwrap()
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (model_path, audio_path) = parse_args()?;

    #[cfg(not(feature = "ffmpeg"))]
        let audio = read_audio_using_symphonia(audio_path);
    #[cfg(feature = "ffmpeg")]
        let audio = read_video_using_ffmpeg(audio_path);

    let classification_results = AudioClassifierBuilder::new()
        .max_results(3) // set max result
        .build_from_file(model_path)? // create a task instance
        .classify(audio)?; // do inference and generate results

    // show formatted result message
    for c in classification_results {
        println!("{}", c);
    }

    Ok(())
}

Use the Session to speed up

The session includes inference sessions (such as TfLite interpreter), input and output buffers, etc. Explicitly using the session can reuse these resources to speed up.

Example: Text Classification

Origin :

use mediapipe_rs::tasks::text::TextClassifier;
use mediapipe_rs::postprocess::ClassificationResult;
use mediapipe_rs::Error;

fn inference(
    text_classifier: &TextClassifier,
    inputs: &Vec<String>
) -> Result<Vec<ClassificationResult>, Error> {
    let mut res = Vec::with_capacity(inputs.len());
    for input in inputs {
        // text_classifier will create new session every time
        res.push(text_classifier.classify(input.as_str())?);
    }
    Ok(res)
}

Use the session to speed up:

use mediapipe_rs::tasks::text::TextClassifier;
use mediapipe_rs::postprocess::ClassificationResult;
use mediapipe_rs::Error;

fn inference(
    text_classifier: &TextClassifier,
    inputs: &Vec<String>
) -> Result<Vec<ClassificationResult>, Error> {
    let mut res = Vec::with_capacity(inputs.len());
    // only create one session and reuse the resources in session.
    let mut session = text_classifier.new_session()?;
    for input in inputs {
        res.push(session.classify(input.as_str())?);
    }
    Ok(res)
}

Use the FFMPEG feature to process video and audio.

When building the library with ffmpeg feature using cargo, users must set the following environment variables:

• FFMPEG_DIR: the pre-built FFmpeg library path. You can download it from https://github.com/yanghaku/ffmpeg-wasm32-wasi/releases.
• WASI_SDK or (WASI_SYSROOT and CLANG_RT), You can download it from https://github.com/WebAssembly/wasi-sdk/releases
• BINDGEN_EXTRA_CLANG_ARGS: set sysroot and target and function visibility for libclang. (The sysroot must be absolute path).

Example:

export FFMPEG_DIR=/path/to/ffmpeg/library
export WASI_SDK=/opt/wasi-sdk
export BINDGEN_EXTRA_CLANG_ARGS="--sysroot=/opt/wasi-sdk/share/wasi-sysroot --target=wasm32-wasi -fvisibility=default"

# Then run cargo

GPU and TPU support

The default device is CPU, and user can use APIs to choose device to use:

use mediapipe_rs::tasks::vision::ObjectDetectorBuilder;

fn create_gpu(model_blob: Vec<u8>) {
    let detector_gpu = ObjectDetectorBuilder::new()
        .gpu()
        .build_from_buffer(model_blob)
        .unwrap();
}

fn create_tpu(model_blob: Vec<u8>) {
    let detector_tpu = ObjectDetectorBuilder::new()
        .tpu()
        .build_from_buffer(model_blob)
        .unwrap();
}

Notice

This work is made possible by Google's work on Mediapipe.

Related Links

• LFX Workspace: A Rust library crate for mediapipe models for WasmEdge NN
• WasmEdge
• MediaPipe
• wasi-nn safe
• wasi-nn specification
• wasi-nn

License

This project is licensed under the Apache 2.0 license. See LICENSE for more details.