Advertisements As it is well known, Xfinity switched to MPEG4 from MPEG2 for their cable compression, with TiVo only providing an update for the Series 3 HD models (HD & HD XL), while leaving Xfinity subscribers with the original Series 3 DVR in the dust. However, with this update came a downside - transferring MPEG4 recordings from a TiVo HD to PC doesn't quite work, leaving you with only the audio, no video. I've read that this is because TiVo uses the Transport-Stream to record MPEG4 recordings, rather than the Program-Stream it normally uses for MPEG2 recordings. However, when TiVo updated the HD boxes to support MPEG4, they never fixed the TiVoToGo to add an option to download the Transport-Stream, meaning that you're left with the Program-Stream to download, which only gives you audio. So, having recently acquired an HD channel package on Xfinity, I ran a test. I went and recorded 2 shows. 1 in Standard Definition, and 1 in High Definition. After both shows were recorded, I transferred them to my computer using pyTivo Desktop and played both output files in VLC. As expected, after transferring the HD program, I was left with audio only. However, after transferring the SD program, I was pretty shocked to discover that it not only recorded the audio of the program, but that it also got the video of it too. After this test, I've came to the conclusion that Xfinity most likely only transitioned their HD channels to MPEG4 and left the SD channels in MPEG2, meaning that if you have a Series 3 (HD, not the original model) DVR, and want to transfer a program to your PC, then SD may be your only option if you don't currently have access to a Series 4 or newer DVR (whether it be not on hand or that you don't want to shell out more money on a DVR that will be used simply for transitioning MPEG4 programs off another DVR).