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使用 Tacotron2 进行文本转语音¶
import IPython
import matplotlib
import matplotlib.pyplot as plt
概述¶
本教程展示了如何使用 torchaudio 中预训练的 Tacotron2 构建文本转语音流程。
文本转语音流程如下:
文本预处理
首先,输入文本被编码为符号列表。在本教程中,我们将使用英文字符和音素作为符号。
频谱图生成
从编码文本生成频谱图。我们使用
Tacotron2模型来完成此操作。时域转换
最后一步是将语谱图转换为波形。从语谱图生成语音的过程也称为声码器(Vocoder)。在本教程中,我们使用了三种不同的声码器: WaveRNN、 Griffin-Lim 以及 Nvidia 的 WaveGlow。
下图展示了整个流程。
所有相关组件都打包在 torchaudio.pipelines.Tacotron2TTSBundle() 中,
但本教程也将涵盖其背后的处理过程。
准备¶
首先,我们安装必要的依赖项。除了
torchaudio,还需要 DeepPhonemizer 来执行基于音素的编码。
# When running this example in notebook, install DeepPhonemizer
# !pip3 install deep_phonemizer
import torch
import torchaudio
matplotlib.rcParams["figure.figsize"] = [16.0, 4.8]
torch.random.manual_seed(0)
device = "cuda" if torch.cuda.is_available() else "cpu"
print(torch.__version__)
print(torchaudio.__version__)
print(device)
Out:
1.12.0
0.12.0
cpu
文本处理¶
基于字符的编码¶
在本节中,我们将介绍基于字符的编码是如何工作的。
由于预训练的 Tacotron2 模型需要特定的符号表集,因此提供了与 torchaudio 中相同的功能。本节主要用于解释编码的基础知识。
首先,我们定义符号集。例如,我们可以使用
'_-!\'(),.:;? abcdefghijklmnopqrstuvwxyz'。然后,我们将输入文本中的每个字符映射到表中对应符号的索引。
以下是此类处理的一个示例。在该示例中,表中未出现的符号将被忽略。
Out:
[19, 16, 23, 23, 26, 11, 34, 26, 29, 23, 15, 2, 11, 31, 16, 35, 31, 11, 31, 26, 11, 30, 27, 16, 16, 14, 19, 2]
如上所述,符号表和索引必须与预训练的 Tacotron2 模型所期望的一致。torchaudio 提供了该转换以及预训练模型。例如,您可以实例化并使用此类转换,如下所示。
Out:
tensor([[19, 16, 23, 23, 26, 11, 34, 26, 29, 23, 15, 2, 11, 31, 16, 35, 31, 11,
31, 26, 11, 30, 27, 16, 16, 14, 19, 2]])
tensor([28], dtype=torch.int32)
The processor 对象接受文本或文本列表作为输入。
当提供文本列表时,返回的 lengths 变量
表示输出批次中每个处理过的标记的有效长度。
中间表示可按以下方式检索。
Out:
['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', '!', ' ', 't', 'e', 'x', 't', ' ', 't', 'o', ' ', 's', 'p', 'e', 'e', 'c', 'h', '!']
基于音素的编码¶
基于音素的编码与基于字符的编码类似,但它使用基于音素的符号表和一个 G2P(字形到音素)模型。
G2P 模型的细节超出了本教程的范围,我们仅查看转换后的效果。
与基于字符的编码情况类似,编码过程应与预训练的 Tacotron2 模型所训练的内容相匹配。
torchaudio 提供了一个用于创建该过程的接口。
以下代码说明了如何创建和使用该流程。在后台,使用 DeepPhonemizer 包创建一个 G2P 模型,并获取 DeepPhonemizer 的作者发布的预训练权重。
Out:
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100%|##########| 63.6M/63.6M [00:04<00:00, 15.3MB/s]
tensor([[54, 20, 65, 69, 11, 92, 44, 65, 38, 2, 11, 81, 40, 64, 79, 81, 11, 81,
20, 11, 79, 77, 59, 37, 2]])
tensor([25], dtype=torch.int32)
请注意,编码后的值与基于字符的编码示例不同。
中间表示形式如下所示。
Out:
['HH', 'AH', 'L', 'OW', ' ', 'W', 'ER', 'L', 'D', '!', ' ', 'T', 'EH', 'K', 'S', 'T', ' ', 'T', 'AH', ' ', 'S', 'P', 'IY', 'CH', '!']
频谱图生成¶
Tacotron2 是我们用来从编码文本生成频谱图的模型。有关该模型的详细信息,请参阅 论文。
使用预训练权重实例化 Tacotron2 模型非常简单,但请注意,输入到 Tacotron2 模型的数据需要经过匹配文本处理器的处理。
torchaudio.pipelines.Tacotron2TTSBundle() 将匹配的模型和处理器捆绑在一起,以便轻松创建流水线。
有关可用的捆绑包及其用法,请参阅 torchaudio.pipelines。
bundle = torchaudio.pipelines.TACOTRON2_WAVERNN_PHONE_LJSPEECH
processor = bundle.get_text_processor()
tacotron2 = bundle.get_tacotron2().to(device)
text = "Hello world! Text to speech!"
with torch.inference_mode():
processed, lengths = processor(text)
processed = processed.to(device)
lengths = lengths.to(device)
spec, _, _ = tacotron2.infer(processed, lengths)
plt.imshow(spec[0].cpu().detach())

Out:
Downloading: "https://download.pytorch.org/torchaudio/models/tacotron2_english_phonemes_1500_epochs_wavernn_ljspeech.pth" to /root/.cache/torch/hub/checkpoints/tacotron2_english_phonemes_1500_epochs_wavernn_ljspeech.pth
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<matplotlib.image.AxesImage object at 0x7fd8fd4d97f0>
请注意,Tacotron2.infer 方法执行多项式采样,因此生成频谱图的过程会引入随机性。

Out:
torch.Size([80, 155])
torch.Size([80, 167])
torch.Size([80, 164])
波形生成¶
生成频谱图后,最后一步是从频谱图中恢复波形。
torchaudio 提供基于 GriffinLim 和
WaveRNN 的声码器。
WaveRNN¶
承接上一节,我们可以从同一个捆绑包中实例化匹配的 WaveRNN 模型。
bundle = torchaudio.pipelines.TACOTRON2_WAVERNN_PHONE_LJSPEECH
processor = bundle.get_text_processor()
tacotron2 = bundle.get_tacotron2().to(device)
vocoder = bundle.get_vocoder().to(device)
text = "Hello world! Text to speech!"
with torch.inference_mode():
processed, lengths = processor(text)
processed = processed.to(device)
lengths = lengths.to(device)
spec, spec_lengths, _ = tacotron2.infer(processed, lengths)
waveforms, lengths = vocoder(spec, spec_lengths)
fig, [ax1, ax2] = plt.subplots(2, 1, figsize=(16, 9))
ax1.imshow(spec[0].cpu().detach())
ax2.plot(waveforms[0].cpu().detach())
torchaudio.save("_assets/output_wavernn.wav", waveforms[0:1].cpu(), sample_rate=vocoder.sample_rate)
IPython.display.Audio("_assets/output_wavernn.wav")

Out:
Downloading: "https://download.pytorch.org/torchaudio/models/wavernn_10k_epochs_8bits_ljspeech.pth" to /root/.cache/torch/hub/checkpoints/wavernn_10k_epochs_8bits_ljspeech.pth
0%| | 0.00/16.7M [00:00<?, ?B/s]
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100%|##########| 16.7M/16.7M [00:00<00:00, 69.3MB/s]
Griffin-Lim¶
使用 Griffin-Lim 声码器与 WaveRNN 相同。您可以使用 get_vocoder 方法实例化声码器对象并传入频谱图。
bundle = torchaudio.pipelines.TACOTRON2_GRIFFINLIM_PHONE_LJSPEECH
processor = bundle.get_text_processor()
tacotron2 = bundle.get_tacotron2().to(device)
vocoder = bundle.get_vocoder().to(device)
with torch.inference_mode():
processed, lengths = processor(text)
processed = processed.to(device)
lengths = lengths.to(device)
spec, spec_lengths, _ = tacotron2.infer(processed, lengths)
waveforms, lengths = vocoder(spec, spec_lengths)
fig, [ax1, ax2] = plt.subplots(2, 1, figsize=(16, 9))
ax1.imshow(spec[0].cpu().detach())
ax2.plot(waveforms[0].cpu().detach())
torchaudio.save(
"_assets/output_griffinlim.wav",
waveforms[0:1].cpu(),
sample_rate=vocoder.sample_rate,
)
IPython.display.Audio("_assets/output_griffinlim.wav")

Out:
Downloading: "https://download.pytorch.org/torchaudio/models/tacotron2_english_phonemes_1500_epochs_ljspeech.pth" to /root/.cache/torch/hub/checkpoints/tacotron2_english_phonemes_1500_epochs_ljspeech.pth
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Waveglow¶
Waveglow 是由 Nvidia 发布的声码器。预训练权重已发布在 Torch Hub 上。可以使用 torch.hub 模块实例化该模型。
# Workaround to load model mapped on GPU
# https://stackoverflow.com/a/61840832
waveglow = torch.hub.load(
"NVIDIA/DeepLearningExamples:torchhub",
"nvidia_waveglow",
model_math="fp32",
pretrained=False,
)
checkpoint = torch.hub.load_state_dict_from_url(
"https://api.ngc.nvidia.com/v2/models/nvidia/waveglowpyt_fp32/versions/1/files/nvidia_waveglowpyt_fp32_20190306.pth", # noqa: E501
progress=False,
map_location=device,
)
state_dict = {key.replace("module.", ""): value for key, value in checkpoint["state_dict"].items()}
waveglow.load_state_dict(state_dict)
waveglow = waveglow.remove_weightnorm(waveglow)
waveglow = waveglow.to(device)
waveglow.eval()
with torch.no_grad():
waveforms = waveglow.infer(spec)
fig, [ax1, ax2] = plt.subplots(2, 1, figsize=(16, 9))
ax1.imshow(spec[0].cpu().detach())
ax2.plot(waveforms[0].cpu().detach())
torchaudio.save("_assets/output_waveglow.wav", waveforms[0:1].cpu(), sample_rate=22050)
IPython.display.Audio("_assets/output_waveglow.wav")

Out:
/usr/local/envs/python3.8/lib/python3.8/site-packages/torch/hub.py:266: UserWarning: You are about to download and run code from an untrusted repository. In a future release, this won't be allowed. To add the repository to your trusted list, change the command to {calling_fn}(..., trust_repo=False) and a command prompt will appear asking for an explicit confirmation of trust, or load(..., trust_repo=True), which will assume that the prompt is to be answered with 'yes'. You can also use load(..., trust_repo='check') which will only prompt for confirmation if the repo is not already trusted. This will eventually be the default behaviour
warnings.warn(
Downloading: "https://github.com/NVIDIA/DeepLearningExamples/zipball/torchhub" to /root/.cache/torch/hub/torchhub.zip
/root/.cache/torch/hub/NVIDIA_DeepLearningExamples_torchhub/PyTorch/Classification/ConvNets/image_classification/models/common.py:13: UserWarning: pytorch_quantization module not found, quantization will not be available
warnings.warn(
/root/.cache/torch/hub/NVIDIA_DeepLearningExamples_torchhub/PyTorch/Classification/ConvNets/image_classification/models/efficientnet.py:17: UserWarning: pytorch_quantization module not found, quantization will not be available
warnings.warn(
Downloading: "https://api.ngc.nvidia.com/v2/models/nvidia/waveglowpyt_fp32/versions/1/files/nvidia_waveglowpyt_fp32_20190306.pth" to /root/.cache/torch/hub/checkpoints/nvidia_waveglowpyt_fp32_20190306.pth
脚本的总运行时间: ( 5 分钟 32.190 秒)