
Whisper Python 示例:语音转文字完整指南
Eric King
Author
Whisper Python 示例:语音转文字完整指南
OpenAI Whisper 是目前最强大的开源语音识别模型之一。在本指南中,你将学习如何使用 Whisper 与 Python,将音频文件高精度地转写成文本。
本教程适合:
- 正在开发语音转文字功能的开发者
- 处理音频数据的数据科学从业者
- 需要完整 Whisper Python 示例 的读者
什么是 OpenAI Whisper?
Whisper 是在 68 万小时多语言音频上训练的自动语音识别(ASR)系统。它可以:
- 支持 99+ 种语言的语音转写
- 自动检测语言
- 将语音翻译为英语
- 处理嘈杂音频与口音
- 处理长音频文件
前置条件
开始之前,请确保已具备:
- 已安装 Python 3.8+
- 包管理工具 pip
- 已安装 FFmpeg(用于音频处理)
- (可选)用于加速的 NVIDIA GPU
第 1 步:安装 Whisper
使用 pip 安装 OpenAI Whisper 包:
pip install openai-whisper
安装 FFmpeg
macOS(使用 Homebrew):
brew install ffmpeg
Ubuntu/Debian:
sudo apt update
sudo apt install ffmpeg
Windows:
请从 ffmpeg.org 下载 FFmpeg,并添加到 PATH。
第 2 步:基础 Whisper Python 示例
下面是一个用于转写音频文件的简单 Python 脚本:
import whisper
# Load the Whisper model
model = whisper.load_model("base")
# Transcribe audio file
result = model.transcribe("audio.mp3")
# Print the transcription
print(result["text"])
输出:
Hello everyone, welcome to today's meeting. We will discuss the project timeline and upcoming milestones.
第 3 步:带错误处理的完整 Python 示例
这是一个更稳健、包含完善错误处理的示例:
import whisper
import os
def transcribe_audio(audio_path, model_size="base"):
"""
Transcribe an audio file using Whisper.
Args:
audio_path (str): Path to the audio file
model_size (str): Whisper model size (tiny, base, small, medium, large)
Returns:
dict: Transcription result with text and segments
"""
try:
# Check if audio file exists
if not os.path.exists(audio_path):
raise FileNotFoundError(f"Audio file not found: {audio_path}")
# Load the Whisper model
print(f"Loading Whisper model: {model_size}")
model = whisper.load_model(model_size)
# Transcribe the audio
print(f"Transcribing: {audio_path}")
result = model.transcribe(audio_path)
return result
except Exception as e:
print(f"Error during transcription: {str(e)}")
return None
# Example usage
if __name__ == "__main__":
audio_file = "sample_audio.mp3"
result = transcribe_audio(audio_file, model_size="base")
if result:
print("\nTranscription:")
print(result["text"])
第 4 步:语言检测进阶示例
Whisper 可以自动检测语言,你也可以手动指定:
import whisper
model = whisper.load_model("base")
# Auto-detect language
result = model.transcribe("audio.mp3")
print(f"Detected language: {result['language']}")
print(f"Transcription: {result['text']}")
# Specify language explicitly
result_en = model.transcribe("audio.mp3", language="en")
result_zh = model.transcribe("audio.mp3", language="zh")
第 5 步:获取时间戳与分段信息
Whisper 提供带时间戳的详细分段信息:
import whisper
model = whisper.load_model("base")
result = model.transcribe("audio.mp3")
# Print full transcription
print("Full Text:")
print(result["text"])
# Print segments with timestamps
print("\nSegments with Timestamps:")
for segment in result["segments"]:
start = segment["start"]
end = segment["end"]
text = segment["text"]
print(f"[{start:.2f}s - {end:.2f}s] {text}")
输出:
Full Text:
Hello everyone, welcome to today's meeting. We will discuss the project timeline.
Segments with Timestamps:
[0.00s - 2.50s] Hello everyone, welcome to today's meeting.
[2.50s - 5.80s] We will discuss the project timeline.
第 6 步:将音频翻译为英语
Whisper 可以直接将非英语语音翻译为英语:
import whisper
model = whisper.load_model("base")
# Translate to English
result = model.transcribe("spanish_audio.mp3", task="translate")
print("Translated text:")
print(result["text"])
第 7 步:批量处理多个音频文件
以下介绍如何批量转写多个文件:
import whisper
import os
from pathlib import Path
def batch_transcribe(audio_directory, model_size="base", output_dir="transcriptions"):
"""
Transcribe all audio files in a directory.
Args:
audio_directory (str): Directory containing audio files
model_size (str): Whisper model size
output_dir (str): Directory to save transcriptions
"""
# Create output directory
os.makedirs(output_dir, exist_ok=True)
# Load model once
model = whisper.load_model(model_size)
# Supported audio formats
audio_extensions = ['.mp3', '.wav', '.m4a', '.flac', '.ogg']
# Process each audio file
audio_files = [
f for f in os.listdir(audio_directory)
if any(f.lower().endswith(ext) for ext in audio_extensions)
]
for audio_file in audio_files:
audio_path = os.path.join(audio_directory, audio_file)
print(f"\nProcessing: {audio_file}")
try:
result = model.transcribe(audio_path)
# Save transcription to file
output_file = os.path.join(
output_dir,
Path(audio_file).stem + ".txt"
)
with open(output_file, "w", encoding="utf-8") as f:
f.write(result["text"])
print(f"✓ Saved: {output_file}")
except Exception as e:
print(f"✗ Error processing {audio_file}: {str(e)}")
# Example usage
batch_transcribe("audio_files/", model_size="base")
第 8 步:导出为 SRT 字幕格式
根据转写结果创建 SRT 字幕文件:
import whisper
def transcribe_to_srt(audio_path, output_path, model_size="base"):
"""
Transcribe audio and save as SRT subtitle file.
Args:
audio_path (str): Path to audio file
output_path (str): Path to save SRT file
model_size (str): Whisper model size
"""
model = whisper.load_model(model_size)
result = model.transcribe(audio_path)
# Generate SRT content
srt_content = ""
for i, segment in enumerate(result["segments"], start=1):
start_time = format_timestamp(segment["start"])
end_time = format_timestamp(segment["end"])
text = segment["text"].strip()
srt_content += f"{i}\n"
srt_content += f"{start_time} --> {end_time}\n"
srt_content += f"{text}\n\n"
# Save SRT file
with open(output_path, "w", encoding="utf-8") as f:
f.write(srt_content)
print(f"SRT file saved: {output_path}")
def format_timestamp(seconds):
"""Convert seconds to SRT timestamp format (HH:MM:SS,mmm)."""
hours = int(seconds // 3600)
minutes = int((seconds % 3600) // 60)
secs = int(seconds % 60)
millis = int((seconds % 1) * 1000)
return f"{hours:02d}:{minutes:02d}:{secs:02d},{millis:03d}"
# Example usage
transcribe_to_srt("video.mp4", "subtitles.srt", model_size="base")
Whisper 模型尺寸对比
根据需求选择合适的模型尺寸:
| 模型 | 参数量 | 速度 | 准确度 | 内存 | 适用场景 |
|---|---|---|---|---|---|
| tiny | 39M | ⭐⭐⭐⭐⭐ | ⭐⭐ | ~1GB | 快速测试、简单音频 |
| base | 74M | ⭐⭐⭐⭐ | ⭐⭐⭐ | ~1GB | 通用 |
| small | 244M | ⭐⭐⭐ | ⭐⭐⭐⭐ | ~2GB | 平衡 |
| medium | 769M | ⭐⭐ | ⭐⭐⭐⭐⭐ | ~5GB | 需要高准确度 |
| large | 1550M | ⭐ | ⭐⭐⭐⭐⭐⭐ | ~10GB | 最佳准确度、嘈杂环境 |
Whisper Python 最佳实践
1. 选择合适的模型尺寸
# Fast and lightweight
model = whisper.load_model("tiny") # Good for testing
# Balanced
model = whisper.load_model("base") # Good for most cases
# High accuracy
model = whisper.load_model("medium") # For important transcriptions
2. 处理长音频
对非常长的音频,可考虑分块处理:
import whisper
from pydub import AudioSegment
def transcribe_long_audio(audio_path, chunk_length_ms=60000):
"""
Transcribe long audio by splitting into chunks.
Args:
audio_path: Path to audio file
chunk_length_ms: Length of each chunk in milliseconds
"""
model = whisper.load_model("base")
# Load audio
audio = AudioSegment.from_file(audio_path)
# Split into chunks
chunks = []
for i in range(0, len(audio), chunk_length_ms):
chunks.append(audio[i:i + chunk_length_ms])
# Transcribe each chunk
full_text = []
for i, chunk in enumerate(chunks):
chunk_path = f"chunk_{i}.wav"
chunk.export(chunk_path, format="wav")
result = model.transcribe(chunk_path)
full_text.append(result["text"])
# Clean up chunk file
os.remove(chunk_path)
return " ".join(full_text)
3. 使用 GPU 加速
如果你拥有 NVIDIA GPU:
import whisper
# Whisper will automatically use GPU if available
model = whisper.load_model("base", device="cuda")
4. 指定语言以提高准确度
# If you know the language, specify it
result = model.transcribe("audio.mp3", language="en")
常见使用场景
播客转写
import whisper
model = whisper.load_model("medium")
result = model.transcribe("podcast_episode.mp3")
# Save transcript
with open("podcast_transcript.txt", "w") as f:
f.write(result["text"])
会议记录
import whisper
from datetime import datetime
model = whisper.load_model("base")
result = model.transcribe("meeting_recording.mp3")
# Create formatted meeting notes
notes = f"""
Meeting Notes - {datetime.now().strftime('%Y-%m-%d')}
========================================
{result["text"]}
"""
with open("meeting_notes.txt", "w") as f:
f.write(notes)
视频字幕
import whisper
model = whisper.load_model("base")
result = model.transcribe("video.mp4")
# Generate VTT subtitle file
vtt_content = "WEBVTT\n\n"
for segment in result["segments"]:
start = format_vtt_timestamp(segment["start"])
end = format_vtt_timestamp(segment["end"])
text = segment["text"].strip()
vtt_content += f"{start} --> {end}\n{text}\n\n"
with open("subtitles.vtt", "w") as f:
f.write(vtt_content)
常见问题排查
问题 1:找不到 FFmpeg
错误:
FileNotFoundError: ffmpeg解决方案:
# Install FFmpeg
# macOS
brew install ffmpeg
# Ubuntu/Debian
sudo apt install ffmpeg
# Windows
# Download from ffmpeg.org and add to PATH
问题 2:显存不足
错误:
RuntimeError: CUDA out of memory解决方案:
# Use a smaller model
model = whisper.load_model("tiny") # Instead of "large"
# Or use CPU
model = whisper.load_model("base", device="cpu")
问题 3:处理速度慢
解决方法:
- 使用更小的模型(tiny 或 base)
- 启用 GPU 加速
- 分块处理音频
- 批量任务使用多进程
性能建议
- 尽量使用 GPU — 可比 CPU 快 10–50 倍
- 选择合适模型 — 简单任务不必使用「large」
- 预处理音频 — 去静音、音量归一化
- 批量处理 — 模型只加载一次,处理多文件
- 使用线程 — 适合 I/O 密集型操作
Whisper Python 与其他方案对比
| 功能 | Whisper Python | Google Speech-to-Text | AssemblyAI |
|---|---|---|---|
| 成本 | 免费(本地) | 按分钟计费 | 按分钟计费 |
| 离线 | ✅ | ❌ | ❌ |
| 准确度 | 高 | 高 | 高 |
| 部署难度 | 中等 | 简单 | 简单 |
| 长音频 | ✅ | ✅ | ✅ |
| 多语言 | ✅ | ✅ | ✅ |
完整示例:可用于生产的脚本
下面是一个完整、可用于生产环境的示例:
#!/usr/bin/env python3
"""
Production-ready Whisper transcription script.
"""
import whisper
import argparse
import os
import json
from pathlib import Path
from datetime import datetime
def transcribe_file(
audio_path,
model_size="base",
language=None,
output_format="txt",
output_dir=None
):
"""
Transcribe an audio file with comprehensive output options.
Args:
audio_path: Path to audio file
model_size: Whisper model size
language: Language code (optional, auto-detected if None)
output_format: Output format (txt, json, srt, vtt)
output_dir: Output directory (default: same as audio file)
"""
# Validate input file
if not os.path.exists(audio_path):
raise FileNotFoundError(f"Audio file not found: {audio_path}")
# Set output directory
if output_dir is None:
output_dir = os.path.dirname(audio_path)
os.makedirs(output_dir, exist_ok=True)
# Load model
print(f"Loading Whisper model: {model_size}")
model = whisper.load_model(model_size)
# Transcribe
print(f"Transcribing: {audio_path}")
transcribe_kwargs = {}
if language:
transcribe_kwargs["language"] = language
result = model.transcribe(audio_path, **transcribe_kwargs)
# Generate output filename
base_name = Path(audio_path).stem
output_path = os.path.join(output_dir, base_name)
# Save based on format
if output_format == "txt":
with open(f"{output_path}.txt", "w", encoding="utf-8") as f:
f.write(result["text"])
elif output_format == "json":
with open(f"{output_path}.json", "w", encoding="utf-8") as f:
json.dump(result, f, indent=2, ensure_ascii=False)
elif output_format == "srt":
srt_content = generate_srt(result["segments"])
with open(f"{output_path}.srt", "w", encoding="utf-8") as f:
f.write(srt_content)
elif output_format == "vtt":
vtt_content = generate_vtt(result["segments"])
with open(f"{output_path}.vtt", "w", encoding="utf-8") as f:
f.write(vtt_content)
print(f"✓ Transcription saved: {output_path}.{output_format}")
print(f" Language: {result['language']}")
print(f" Duration: {result['segments'][-1]['end']:.2f}s")
return result
def generate_srt(segments):
"""Generate SRT subtitle content."""
srt = ""
for i, segment in enumerate(segments, start=1):
start = format_timestamp(segment["start"])
end = format_timestamp(segment["end"])
text = segment["text"].strip()
srt += f"{i}\n{start} --> {end}\n{text}\n\n"
return srt
def generate_vtt(segments):
"""Generate VTT subtitle content."""
vtt = "WEBVTT\n\n"
for segment in segments:
start = format_vtt_timestamp(segment["start"])
end = format_vtt_timestamp(segment["end"])
text = segment["text"].strip()
vtt += f"{start} --> {end}\n{text}\n\n"
return vtt
def format_timestamp(seconds):
"""Format timestamp for SRT."""
hours = int(seconds // 3600)
minutes = int((seconds % 3600) // 60)
secs = int(seconds % 60)
millis = int((seconds % 1) * 1000)
return f"{hours:02d}:{minutes:02d}:{secs:02d},{millis:03d}"
def format_vtt_timestamp(seconds):
"""Format timestamp for VTT."""
hours = int(seconds // 3600)
minutes = int((seconds % 3600) // 60)
secs = int(seconds % 60)
millis = int((seconds % 1) * 1000)
return f"{hours:02d}:{minutes:02d}:{secs:02d}.{millis:03d}"
def main():
parser = argparse.ArgumentParser(
description="Transcribe audio files using OpenAI Whisper"
)
parser.add_argument("audio", help="Path to audio file")
parser.add_argument(
"--model",
default="base",
choices=["tiny", "base", "small", "medium", "large"],
help="Whisper model size"
)
parser.add_argument(
"--language",
default=None,
help="Language code (e.g., 'en', 'zh', 'es')"
)
parser.add_argument(
"--output-format",
default="txt",
choices=["txt", "json", "srt", "vtt"],
help="Output format"
)
parser.add_argument(
"--output-dir",
default=None,
help="Output directory"
)
args = parser.parse_args()
transcribe_file(
args.audio,
model_size=args.model,
language=args.language,
output_format=args.output_format,
output_dir=args.output_dir
)
if __name__ == "__main__":
main()
用法:
# Basic usage
python transcribe.py audio.mp3
# With options
python transcribe.py audio.mp3 --model medium --language en --output-format srt
# Save to specific directory
python transcribe.py audio.mp3 --output-dir ./transcriptions
总结
本 Whisper Python 示例指南涵盖使用 OpenAI Whisper 进行语音转文字入门所需的全部内容。无论是播客、会议还是字幕制作,Whisper 都提供了强大且免费的音频转文本方案。
要点:
- Whisper 免费且开源
- 支持 99+ 种语言
- 可离线运行(无需调用 API)
- 在大多数场景下准确度很高
- 易于集成到 Python 项目
若在生产环境中需要实时转写或 API 访问,可考虑 SayToWords 等云端方案,其通过 API 提供基于 Whisper 的转写服务。
准备开始了吗? 安装 Whisper,今天就转写你的第一个音频文件。