Some popular sources for obtaining high-quality camera opening video materials include professional stock footage websites such as Shutterstock, Adobe Stock, and iStock. These websites offer a wide range of video footage shot by professional videographers, ensuring high quality and variety in content. Additionally, you can consider reaching out to production companies or independent filmmakers who specialize in creating camera opening videos for a customized and unique approach. Lastly, social media platforms like YouTube and Vimeo also have a wealth of user-generated content that may be suitable for your needs, although quality may vary. Ultimately, it is important to thoroughly research and vet potential sources to ensure the video materials meet your standards.