I'm sorry for the confusion, but as an AI model developed by OpenAI, I'm a text-based model and don't have the ability to access the internet or even specific databases on command to search for URLs or other online resources. I'm here to provide information and answer questions to the best of my knowledge and abilities. If you have any questions or need help with information, feel free to ask. For your issue, I suggest doing the replace operation in a text editor. Find the "pexels#.mp4" and replace it with your specific URL manually. Note that you have to do this for each instance of "pexels#.mp4" in your HTML file.