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# Copyright (c) Meta Platforms, Inc. and affiliates. | |
# All rights reserved. | |
# | |
# This source code is licensed under the license found in the | |
# LICENSE file in the root directory of this source tree. | |
import torch | |
import torchmetrics | |
from ..data.audio_utils import convert_audio | |
from ..modules.chroma import ChromaExtractor | |
class ChromaCosineSimilarityMetric(torchmetrics.Metric): | |
"""Chroma cosine similarity metric. | |
This metric extracts a chromagram for a reference waveform and | |
a generated waveform and compares each frame using the cosine similarity | |
function. The output is the mean cosine similarity. | |
Args: | |
sample_rate (int): Sample rate used by the chroma extractor. | |
n_chroma (int): Number of chroma used by the chroma extractor. | |
radix2_exp (int): Exponent for the chroma extractor. | |
argmax (bool): Whether the chroma extractor uses argmax. | |
eps (float): Epsilon for cosine similarity computation. | |
""" | |
def __init__(self, sample_rate: int, n_chroma: int, radix2_exp: int, argmax: bool, eps: float = 1e-8): | |
super().__init__() | |
self.chroma_sample_rate = sample_rate | |
self.n_chroma = n_chroma | |
self.eps = eps | |
self.chroma_extractor = ChromaExtractor(sample_rate=self.chroma_sample_rate, n_chroma=self.n_chroma, | |
radix2_exp=radix2_exp, argmax=argmax) | |
self.add_state("cosine_sum", default=torch.tensor(0.), dist_reduce_fx="sum") | |
self.add_state("weight", default=torch.tensor(0.), dist_reduce_fx="sum") | |
def update(self, preds: torch.Tensor, targets: torch.Tensor, | |
sizes: torch.Tensor, sample_rates: torch.Tensor) -> None: | |
"""Compute cosine similarity between chromagrams and accumulate scores over the dataset.""" | |
if preds.size(0) == 0: | |
return | |
assert preds.shape == targets.shape, ( | |
f"Preds and target shapes mismatch: preds={preds.shape}, targets={targets.shape}") | |
assert preds.size(0) == sizes.size(0), ( | |
f"Number of items in preds ({preds.shape}) mismatch ", | |
f"with sizes ({sizes.shape})") | |
assert preds.size(0) == sample_rates.size(0), ( | |
f"Number of items in preds ({preds.shape}) mismatch ", | |
f"with sample_rates ({sample_rates.shape})") | |
assert torch.all(sample_rates == sample_rates[0].item()), "All sample rates are not the same in the batch" | |
device = self.weight.device | |
preds, targets = preds.to(device), targets.to(device) # type: ignore | |
sample_rate = sample_rates[0].item() | |
preds = convert_audio(preds, from_rate=sample_rate, to_rate=self.chroma_sample_rate, to_channels=1) | |
targets = convert_audio(targets, from_rate=sample_rate, to_rate=self.chroma_sample_rate, to_channels=1) | |
gt_chroma = self.chroma_extractor(targets) | |
gen_chroma = self.chroma_extractor(preds) | |
chroma_lens = (sizes / self.chroma_extractor.winhop).ceil().int() | |
for i in range(len(gt_chroma)): | |
t = int(chroma_lens[i].item()) | |
cosine_sim = torch.nn.functional.cosine_similarity( | |
gt_chroma[i, :t], gen_chroma[i, :t], dim=1, eps=self.eps) | |
self.cosine_sum += cosine_sim.sum(dim=0) # type: ignore | |
self.weight += torch.tensor(t) # type: ignore | |
def compute(self) -> float: | |
"""Computes the average cosine similarty across all generated/target chromagrams pairs.""" | |
assert self.weight.item() > 0, "Unable to compute with total number of comparisons <= 0" # type: ignore | |
return (self.cosine_sum / self.weight).item() # type: ignore | |