itproject-code/pipeline/feature_extractors.py

from abc import ABC
import json
import logging
import os
import random
import subprocess
from ast import literal_eval
from pipeline.utils import SourceMedia, Source, Feature, Interval

# for loudness detection
import soundfile
import pyloudnorm

logger = logging.getLogger(__name__)

class FeatureExtractor(ABC):
    """Feature extractor interface."""
    # TODO: #API -- decide if .features will be a member variable
    def _run_get_output(self, cmd: list, cwd:str=".") -> str:
        """Run a command and return the output as a string

        Defined to be mocked out in tests via unittest.mock.patch
        """
        return subprocess.run(cmd, stdout=subprocess.PIPE, cwd=cwd).stdout.decode("utf-8")

    def setup(self):
        """Setup the feature extractor -- validate input files & config"""

    def run(self):
        """Run the feature extractor -- extract features"""

    def teardown(self):
        """Teardown the feature extractor -- clean up any temporary files created during setup"""

class LaughterFeatureExtractor(FeatureExtractor):
    """Feature extractor for laughter detection.

    This class is responsible for extracting features corresponding to laughter in media files.

    Here:

     setup() is used to validate input files & config, which may involve processing video files to extract audio

     run() is used to extract features from the audio using jrgillick's laughter-detection

     teardown() is used to clean up any temporary files created during setup according to the config

    See: https://github.com/jrgillick/laughter-detection for the laughter-detection library
    """

    def __init__(self, input_files=None, config=None):
        """It is expected that input_files is a SourceMedia object"""
        self.input_files = input_files
        self.config = config
        self.features = []

    def _laughdetect(self, audio_file) -> list:
        """Run laughter detection on the audio file

        Returns a list of 2-tuples, each representing a laugh instance in the audio file
        """
        laugh_detector_dir = "/home/robert/mounts/980data/code/laughter-detection/"
        laugh_detector_script = "segment_laughter.py"
        # fake output for testing
        # laugh_detector_path = "tests/fake_segment_laughter.py"
        laugh_detector_cmd = ["python", f"{laugh_detector_dir}{laugh_detector_script}",
                              f"--input_audio_file={audio_file}"]

        # run command, capture output, ignore exit status
        # use self._run_get_output to allow mocking in tests
        laugh_output = self._run_get_output(laugh_detector_cmd, laugh_detector_dir)

        # ↑ have to include cwd to keep laughter-detection imports happy
        # also, it isn't happy if no output dir is specified but we get laughs so it's grand

        # laughs are lines in stdout that start with "instance:", followed by a space and a 2-tuple of floats
        # so jump to the 10th character and evaluate the rest of the line
        return [literal_eval(instance[10:])
                for instance in laugh_output.splitlines()
                if instance.startswith("instance: ")]

    def _adjust_features(self):
        """Adjust features according to config

        Generically, this ensures features conform to config - min/max feature length, etc.

        In the context of LaughterFeatureExtractor, there is some secret sauce: things that
        cause a laugh generally /precede/ the laugh, so we want more team before the detected start
        than at the end. For example, for a minimum feature length of 15s, we might prepend 10 seconds,
        and append 5 seconds (for example), or 12s and 3s. We may wish to do this pre/post adjustment
        for all laughter features found, regardless of length.

        TODO: figure out how we're going to handle length adjustments
        TODO: config for length adjustments per design doc
        TODO: play with numbers more to see what works best
        """
        PREPEND = 7.0
        APPEND = 3.0

        for feature in self.features:
            # do the pre & post adjustment
            feature.interval.move_start(-PREPEND, relative=True)
            feature.interval.move_end(APPEND, relative=True)

    def setup(self):
        """Setup the laughter feature extractor -- validate input files & config

        jrgillick's laughter-detection library can work with AV files directly

        TODO: validate input files
        TODO: handle config
        """
        logger.debug("LaughterFeatureExtractor setup")

        # Validate input files
        if not self.input_files:
            raise ValueError("No input files provided")

        # TODO: convert video to audio if needed

    def run(self):
        """Extract laughter features for each input file"""
        if self.input_files:
            for file in self.input_files:
                # adjust this call for better test mocking
                laughs = self._laughdetect(file.path)
                for laugh in laughs:
                    start, end = laugh
                    self.features.append(Feature(interval=Interval(start=start, end=end),
                                                 source=file, feature_extractor="laughter"))
                    # TODO: implement options eg minimum feature length

        # adjust features
        self._adjust_features()

    def teardown(self):
        pass

class RandomFeatureExtractor(FeatureExtractor):
    """Feature extractor for random feature generation.

    This class is responsible for generating random features for testing purposes.

    Here:

     setup() is used to validate input files & config

     run() is used to generate random features

     teardown() is used to clean up any temporary files created during setup according to the config
    """
    NUM_FEATURES = 5
    MAX_DURATION = 20.0

    def __init__(self, input_files=None, config=None):
        """It is expected that input_files is a SourceMedia object"""
        self.input_files = input_files
        self.config = config
        self.features = []

    def setup(self):
        """Setup the random feature extractor -- validate input files & config"""
        logger.debug("RandomFeatureExtractor setup")

        # Validate input files
        if not self.input_files:
            raise ValueError("No input files provided")

    def run(self):
        """Generate random features for each input file"""
        # check self.input_files is of type SourceMedia
        if not self.input_files or not isinstance(self.input_files, SourceMedia):
            raise ValueError("No input files provided")

        for file in self.input_files:
            for _ in range(self.NUM_FEATURES):
                # round to 3 decimal places
                duration = random.random() * self.MAX_DURATION
                start = random.random() * file.duration() - duration
                self.features.append(Feature(interval=Interval(start=start, duration=duration),
                                             source=file, feature_extractor="random"))

    def teardown(self):
        pass


class LoudAudioFeatureExtractor(FeatureExtractor):
    """Feature extractor for loud audio detection.

    This class is responsible for extracting features corresponding to loud audio in media files.

    Here:

     setup() is used to validate input files & config, and extracting audio

     run() uses pyloudnorm to detect loud audio

     teardown() is used to clean up temporary files created during setup (if specified by config)
    """
    def __init__(self, input_files=None, config=None):
        if not input_files:
            raise ValueError("No input files provided!")
        self.input_files = input_files
        self.config = config
        self.features = []

    def _audio_file_from_path(self, path: str) -> str:
        """Return the audio file path given a video file path

        Example:
          - in = "/path/to/video.mp4"
          - out = "/tmp/video.mp4.wav"
        """
        OUTPUT_DIR = "/tmp"
        return f"{OUTPUT_DIR}/{os.path.basename(path)}.wav"

    def _loudnorm(self, audio_file):
        """Run pyloudnorm on the audio file"""
        data, rate = soundfile.read(audio_file) # load audio (with shape (samples, channels))
        meter = pyloudnorm.Meter(rate=rate,block_size=0.3) # create BS.1770 meter

        loudnesses = []
        loudness_features = []
        window_size = int(rate * 0.5) # 500ms
        stride_size = int(rate * 0.5) # 500ms -- no overlap

        # for w in range(data.shape[0]//100):
        #     loudnesses.append(meter.integrated_loudness(data[w:w+int(0.3*rate),0:2]))
        for w in range(0, len(data)-window_size, stride_size):
            window = data[w:w+window_size, 0:2] # extract window
            loudnesses.append( (w/rate, meter.integrated_loudness(window)) )

        for timecode, loudval in sorted([l for l in loudnesses if float(l[1]) != float("-inf")], key=lambda x: x[1], reverse=True):
            # print(f"Timecode: {timecode}, Loudness: {loudval}")
            loudness_features.append((timecode, round(loudval, 3))) # round to 3 DP

        return loudness_features

    def setup(self):
        """extract audio from video files to be processed by pyloudnorm

        TODO: config -- hardcoded for now
        """
        # pyloudnorm expects WAV files
        for file in self.input_files:
            audio_file = self._audio_file_from_path(file.path)
            # ffmpeg -i input.mp4 -vn -acodec pcm_s16le output.wav
            subprocess.run(["ffmpeg", "-y", "-i", file.path, "-vn", "-acodec", "pcm_s16le", audio_file],
                           stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    def run(self):
        """Use pyloudnorm to detect loud audio"""
        for file in self.input_files:
            audio_file = self._audio_file_from_path(file.path)
            loudnesses = self._loudnorm(audio_file)
            for time, loudness in loudnesses:
                self.features.append(Feature(interval=Interval(start=time, duration=0.500),
                                             source=file, feature_extractor="loudness",
                                             score=loudness))


class VideoActivityFeatureExtractor(FeatureExtractor):
    """Feature extractor for video activity detection.

    This class is responsible for extracting features corresponding to high activity in video files.

    Uses ffmpeg's scdet filter with threshold of zero.

    Here:

     setup() is used to validate input files & config

     run() is used to extract features from the video using OpenCV

     teardown() is used to clean up any temporary files created during setup according to the config

    #TODO: minimum duration -- consider whether to do here, or expand duration post-consolidation
    """
    def __init__(self, input_files=None, config=None):
        if not input_files:
            raise ValueError("No input files provided!")
        self.input_files = input_files
        self.config = config
        self.features = []

    def _scdet(self, video_file):
        """Run scdet filter on the video file"""
        ffmpeg_cmd = ["ffmpeg", "-i", video_file, "-vf", "scdet=threshold=0", "-f", "null", "-"]
        # output is of the form:
        #   [scdet @ 0x7f0798003d00] lavfi.scd.score: 0.031, lavfi.scd.time: 23.65
        #   [scdet @ 0x7f0798003d00] lavfi.scd.score: 0.006, lavfi.scd.time: 23.70
        # capture output, extract time & score
        scdet_output = subprocess.run(ffmpeg_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE).stderr.decode("utf-8")
        # extract time & score
        scores = []
        for line in scdet_output.splitlines():
            if "lavfi.scd.score" in line:
                scores.append( (float(line.split(",")[1].split(":")[1]),
                                float(line.split(",")[0].split(":")[1]))
                                )
        return scores

    def _nonoverlap_mean(self, scores, window_size=0.500) -> list:
        """Take the mean of non-overlapping windows of scores

        Input: list of tuples in the format (time, score)
        Output: list of tuples in the format (time, mean_score) (reduced set)
        """
        means = []
        current_window = []
        current_window_start = 0.0

        for time, score in scores:
            if time - current_window_start > window_size:
                # calculate mean of current window
                mean_score = sum([s for _, s in current_window]) / len(current_window)
                means.append((current_window_start, round(mean_score, 3)))
                # reset window
                current_window = []
                current_window_start = time
            current_window.append((time, score))

        return means

    def _drop_lowest(self, scores, percent=33):
        """Drop the lowest n% scores from the list"""
        scores = sorted(scores, key=lambda x: x[1], reverse=True)
        return scores[:int(len(scores) * (percent / 100))]

    def setup(self):
        pass

    def run(self):
        for file in self.input_files:
            scores = self._scdet(file.path)
            means = sorted(self._nonoverlap_mean(scores), key=lambda x: x[1], reverse=True)
            for time, score in self._drop_lowest(means, 66):
                self.features.append(Feature(interval=Interval(start=time, duration=0.500),
                                             source=file, feature_extractor="videoactivity",
                                             score=score))

    def teardown(self):
        pass


class JSONFeatureExtractor(FeatureExtractor):
    """(Re-)create features from a JSON file

    The JSON file can have one of two formats:
      - the format produced by the pipleline (@see: video_producers.py:JSONProducer)
      - a simplified format which is easier for manual creation
    """

    def __init__(self, input_files=None, config=None):
        if not input_files:
            raise ValueError("No input files provided!")
        self.input_files = input_files
        self.config = config
        self.features = []

    def setup(self):
        pass

    def _interval_from_dict(self, d):
        return Interval(start=d["start"], duration=d["duration"])

    def _source_from_dict(self, d):
        return Source(d["source"], d["path"], d["provider"])

    def _read_json_from_file(self, file):
        """Read a JSON file and return the contents

        Method exists to allow for mocking in tests
        """
        with open(file, "r") as f:
            return json.load(f)

    def run(self):

        # only pipeline JSON format for now
        # TODO: add support for simplified format
        for file in self.input_files:
            features_from_json = self._read_json_from_file(file.path)

            for feature in features_from_json:
                self.features.append(Feature(interval=self._interval_from_dict(feature["interval"]),
                                             source=self._source_from_dict(feature["source"]),
                                             feature_extractor=feature["feature_extractor"],
                                             score=feature["score"]))

    def teardown(self):
        pass