suelarue ,
Qualtrics capabilities for audio/video embedded in the survey are very good. However, we always opt to give the information by verbatim as well, in addition to video/audio.Giving people the option helps. If that is not possible, because of the very low instance of audio/video not working with Qualtrics surveys, in my experience losing sample is low but it all depending on how long the video/audio lasts, and the quality of the content. Is it dry? Does it go on too long? There are many considerations for adding in audio/video.
I once assisted a company that had a survey going out to the deaf community. They had every question translated into American Sign Language (ASL) so the community could have the option of reading or watching the question, and all its answers. We found that there was no significant drop off with adding these videos because they could either take the survey by video or just read the words. A good percentage opted to take it by visual words (faster). We did extensive testing using multiple devices and browsers and did not have anyone who communicated in the feedback of that survey that they could not see or heard the video.
I hope that is helpful.

Thank you ThomasW