pyTivo Serving HD .tivo Files

[christoman]

I am in the process of setting up a Windows Home Server box as a pyTivo media server. It is working great.

One of the movies I put on the server is an HD movie I had previously transferred to the PC using Tivo Desktop. I thought that by not needing to transcode, transfer speed would be excellent. I have found, however, that it is much slower than realtime (7.26 mb/s, 3 hours to transfer a 1 hour 40 min. movie). By comparison, transferring the same movie between two THDs is much faster than realtime (still in progress, but it is obviously much faster).

Is this indicative of what others have seen? I though the overhead would be minimal using the native format. Is there decryption happening at the Tivo that is causing this? I am wondering if I would be better off to convert to MPG in VRD vs. keeping the original file.

[wmcbrine]

I'm kind of surprised it's that slow. My guess would've been a similar speed for .TiVo and plain MPEG-2 files, but I've seen plain MPEG-2 HD files come in at near real-time.

The .TiVo format is not native; it's a program stream, encrypted, with the metadata (description, etc.) prefixed. Natively, the TiVo stores its programs in a modified transport stream, as I understand it. So, when uploading to or downloading from the TiVo, the most time-consuming step is remuxing (done by the TiVo box). TiVo-to-TiVo transfers can bypass this step, so they're faster.