Hauppauge PVR 2 1512 bitrate vs. DVD disk space

[gliebisch]

In a thread on this forum, I found a guideline on planning bit rate for capture vs available DVD disk space, taking into consideration length of program. While the numbers made sense to some extent, e.g 720p 120 Min 12.0 variable rate fills a dual layer DVD, what I did not understand was when the writer then quoted 1080i, 120min 9.0 variable rate on a dual layer DVD. He was apparently yielding to a lower capture bit rate in order to capture 1080i. However, is it not true that you can't display 1080i from a DVD at all? So is that configuration not invalid?

Also, when the source is 1080i, and I want to burn to a DVD ultimately, is it better to use the video scaler in the PVR 2 to convert it down while it is recording, or to capture at 1080i and then use an external program to scale it later to 720p? It seems the internal scaler might tax resources on a slow computer used for capture.

[jagabo]

You can put any kind of video you want on a DVD disc. The issue is what can play it. Regular DVD players can only play MPEG 2 video encoded with specific parameters, authored into movie DVD format with IFO, BUP, and VOB files, and with a specific file system. Some Blu-ray players have built in media players that can play video files of many types and codecs from a disc.

If you know what you're doing you can do a better job of downscaling than the PVR2 can.

[gliebisch]

Sure, I understand that it could be saved on the DVD as an MP4 file, for example. I should have stated that I meant in the DVD Video format. For the second part of my question on downscaling, I've always used the AVS4YOU suite of video programs that seem to be able to convert anything. I'm working through an error message with them right now so that i can try outboard downscaling instead of the internal downscaling in the PVR 2.

[jman98]

That Hauppauge device really shouldn't be using the PC resources for anything except just writing the captured video and audio to the disk drive. That device has its own encoding chip, so while Hauppauge sets up minimal requirements for PCs for its devices, I would think that's more to do with the software it runs than anything else. So it should be OK to have the device downscale if it can do that. But most of us here would prefer to use AviSynth for this kind of thing after capturing at whatever the video's native resolution is.

Without a link to whatever you read, we can't check it to see if your understanding is correct or if what the author wrote is a good idea.

[jagabo]

The site you referred to may have been making an AVCHD disc -- HD video on a DVD disc that can be played by most Blu-ray players.

If you're going to make a standard def movie DVD you want to capture at as high a bitrate as possible to get the best quality. Then inverse telecine (for film sources), downscale, convert to MPEG 2, and author for DVD.

I have no idea what's possible in AVS4YOU or what quality it can deliver.