There is much to praise for providing such diverse educational material, for free, to the public. I could fill a page with how valuable this is. But presently I am here to provide some hopefully constructive criticism.
For all the time and effort, that so many people surely must have put into each of these video lectures—lecturers preparing for their presentation, guests traveling there, the camera operator, the people that mix and edit it for the podcast—for all that, I am dismayed that more care was not taken in the capture and recording of the audio content.
I spent some time during high school in audio-video work. Even then as a teenager I would have been embarrassed at the poor quality of the recording, and would have insisted that the audio source come from the microphone preamplifier directly, rather than what appears to be a "mic'ed speaker" or the like.
I don't mean to offend anyone, but as this quality issue is apparent to varying degrees on all of the video podcasts in the series that I watched, the problem seems systemic. $50 and a trip to Radio Shack for cables and/or connectors might be all that is needed to tap the audio closer to the source before it is distorted.
Again, there is much to be praised about this content. For just a little more effort the quality and listenability could be increased several-fold.
