greeting and thanks for taking the time to provide feedback/questions
I want to let you know that some of the difference you might notice is due to the compression mechanismes that are used to upload from the local device to Azure. MP4 is difficult to compress further compared to for example office documents.
Now if you notice something particularly painful for you or if you think that something is going wrong, i would love to understand better. please provide more details and feedback in general and we will be glad to at least try to answer.