How to Extract MP3 Files from a PDF Using Python

To extract MP3 files embedded in a PDF, you first need to install several Python libraries for PDF handling, image conversion, OCR, and audio processing.

Install the required libraries:

pip install PyPDF2
pip install pdfminer.six
pip install pdf2image
pip install pytesseract
# Install ffmpeg appropriate for your OS and add it to the system PATH

Import the libraries in your script:

import PyPDF2
import pdf2image
import pytesseract
import subprocess
import os

Define a function to extract plain text from the PDF pages:

def extract_text_from_pdf(pdf_path):
    text = ""
    with open(pdf_path, "rb") as file:
        reader = PyPDF2.PdfFileReader(file)
        num_pages = reader.numPages
        for page_num in range(num_pages):
            page = reader.getPage(page_num)
            text += page.extractText()
    return text

Define a function to convert each PDF page to an image file:

def extract_images_from_pdf(pdf_path, output_dir):
    images = pdf2image.convert_from_path(pdf_path)
    image_paths = []
    for i, image in enumerate(images):
        image_path = os.path.join(output_dir, f"page_{i+1}.png")
        image.save(image_path, "PNG")
        image_paths.append(image_path)
    return image_paths

Define a function to run OCR on the extracted images and collect the recognized text:

def extract_text_from_images(image_paths):
    text = ""
    for image_path in image_paths:
        image_text = pytesseract.image_to_string(image_path)
        text += image_text
    return text

Define a function that searches the combined text for an MP3 header ("ID3") and writes the binary data to a file:

def extract_mp3_from_text(text, output_path):
    mp3_start = text.find("ID3")  # assume MP3 starts with ID3 tag
    if mp3_start != -1:
        mp3_data = text[mp3_start:]
        with open(output_path, "wb") as file:
            file.write(mp3_data.encode("latin1"))
        return True
    return False

Example usage that ties all steps together:

pdf_path = "path/to/your/pdf/file.pdf"
output_dir = "path/to/your/output/directory"
output_path = "path/to/your/output/mp3/file.mp3"

# Extract text from PDF
pdf_text = extract_text_from_pdf(pdf_path)
# Extract images from PDF
image_paths = extract_images_from_pdf(pdf_path, output_dir)
# OCR images to get additional text
image_text = extract_text_from_images(image_paths)
# Combine both sources of text
combined_text = pdf_text + image_text
# Attempt to extract MP3
success = extract_mp3_from_text(combined_text, output_path)
if success:
    print("成功提取 MP3 文件！")
else:
    print("未找到 MP3 文件！")

Note that this is a simplified example; real PDFs may have different structures, and OCR may require tuning for accurate results.