Not technically cryptography, but hiding data can certainly aid in the protection of said data, especially if the data is further protected by a modern encryption algorithm. That said, onto the question:
Would it be possible to use steganography to hide meaningful amounts of data in a video and retain that data if it were uploaded to YouTube? Would YouTube compression possibly interfere with the hidden data? If technically possible, would it be a viable method of hiding data you wanted available to anyone who knew where to look and, if applicable, knew how to decrypt the data?
And, if possible or viable, do you think it’s common? Perhaps using those copious low-quality text to speech videos?