hauppauge hd pvr/arcsoft tme bitrate question

[romanticwarrior]

hi there,
i'm currently knocking out my first captures of hd material and making avchd discs with some success.it's a great little box!

can anyone tell me what is the minimum bitrate i can use with NO perceivable loss of picture quality ?
ie is there any quality loss capturing a 2 hour hd movie at 5mbps as the pvr manual suggests?

if i capture at 9mbps and burn to a dl dvd will the difference be signifigant?

[DVWannaB]

test it and let us know. we would all benefit from your report.

[jagabo]

can anyone tell me what is the minimum bitrate i can use with NO perceivable loss of picture quality ?

No, every program is different. Try recording a video test pattern from a channel that's off air. You can get away with tiny bitrates. Try the same with a busy seen where everything on the screen is moving (like a shot of a sunset reflecting off ocean waves, or a sparse tree backlit by the sun on a windy day) and it will require huge amounts of bitrate. 1080i material usually takes more bitrate than 720p (because when showing movies most of the frames are simple repeats -- repeating the same frame costs almost no bitrate).

I set my HD PVR at VBR Peak with the bitrate sliders turned all the way up. Doing this shots that require lots of bitrate get it, shots that don't don't.

[DVWannaB]

jagabo, wouldnt a VBR recording with max bitrate at the highest level do the same thing as Peak VBR recording? Or maybe I am misunderstanding the concept of each. Just seems they are both very similar to each other.

I would like to see SW updated to include a "Smart VBR" setting. Where the broadcast bitrate is what is recorded.

[jagabo]

jagabo, wouldnt a VBR recording with max bitrate at the highest level do the same thing as Peak VBR recording? Or maybe I am misunderstanding the concept of each. Just seems they are both very similar to each other.

I'm not exactly sure what the difference is between the VBR peak and average modes is. I have never seen any clear explanation from Hauppauge. It's also rather hard to test without some reproducible source. When recording broadcast you can't get exactly the same video in several successive recordings. I just did what experimenting I could when I first got the HD PVR and decided to set my cable box to passthrough mode (analog output is the same format as the source) and set the HD PVR to VBR peak mode. I am generally more interested in quality than small file size.

I would like to see SW updated to include a "Smart VBR" setting. Where the broadcast bitrate is what is recorded.

The PVR receives an analog signal. It has no way of knowing what the digital broadcast bitrate is. And if the broadcast isn't h.264 encoded (all OTA broadcast in the USA is MPEG 2) it wouldn't make any sense to use the same bitrate. Even if the broadcast is h.264 the PVR's encoder may be more or less efficient than the broadcast encoder so the same bitrate still wouldn't apply. And finally, the analog signal received by the HD PVR isn't necessarily the same as the signal that's broadcast. For example, a cable box can be set to convert everything to 1080i at the analog output.