For discussion’s sake – while I don’t know the specific nature of your videos, my guess is that they might be demonstrating various techniques or other content in which simply hearing the audio of the video wouldn’t deliver the full context of the content. If making that content accessible is something you’d want to do, you’d likely want to start with a written description of what takes place in the video. Beyond that, high contrast vector images or diagrams showcasing specific parts of the technique would certainly help.
The ADA statute identifies who is a person with a disability, who has obligations under the ADA, general non-discrimination requirements and other basic obligations. It delegates fleshing out those obligations to federal agencies. The agencies issue regulations and design standards. The regulations have the details on the rights of people with disabilities and responsibilities of employers, state and local governments, transportation providers, businesses and non-profit organizations. The design standards specify how many entrances need to be accessible, how many toilet rooms and the design for those elements. To know what the ADA requires, you need to read the law, regulations and design standards.
In some circumstances, longer and more detailed text will be necessary to convey the same meaningful information that other visitors to the website can see. For example, a map showing the locations of neighborhood branches of a city library needs a tag with much more information in text format. In that instance, where the map conveys the locations of several facilities, add a “longdesc” tag that includes a text equivalent description of each location shown on the map – e.g., “City Center Library, 433 N. Main Street, located on North Main Street between 4th Avenue and 5th Avenue.”
One of the first major ADA lawsuits, Paralyzed Veterans of America v. Ellerbe Becket Architects and Engineers (PVA 1996) was focused on the wheelchair accessibility of a stadium project that was still in the design phase, MCI Center (now known as Capital One Arena) in Washington, D.C. Previous to this case, which was filed only five years after the ADA was passed, the DOJ was unable or unwilling to provide clarification on the distribution requirements for accessible wheelchair locations in large assembly spaces. While Section 4.33.3 of ADAAG makes reference to lines of sight, no specific reference is made to seeing over standing patrons. The MCI Center, designed by Ellerbe Becket Architects & Engineers, was designed with too few wheelchair and companion seats, and the ones that were included did not provide sight lines that would enable the wheelchair user to view the playing area while the spectators in front of them were standing. This case and another related case established precedent on seat distribution and sight lines issues for ADA enforcement that continues to present day.
Most recently, however, pizza chain Domino's has been brought under suit for their website not being accessible for specialty ordering. The U.S. Supreme Court refused to review the case, instead upholding the decision of the 9th U.S. Circuit Court of Appeals who said the “alleged inaccessibility of Domino’s website and app impedes access to the goods and services of its physical pizza franchises—which are places of public accommodation.”