Is encoding to MPEG-2 VBR on the fly viable?

[MrMungus]

Trying to figure out the best bitrates for differnet sources, including VHS tape, SVHS, etc. Wondering if I should even bother trying VBR encoding on the fly or not. Can VBR on the fly even work properly or is that something that's only beneficial if the encoding process involves more than one pass? Thoughts?

And since we're on the subject of different bitrates for sources of different quality, what bitrate are you using for VHS, etc?

[Sulik]

VBR encoding on the fly is possible, but it depends a lot on the encoder used (many SW including HW encoders perform VBR as CBR with no padding on easy scenes).

I always had got results with real-time VBR capturing ATI MMC 7.7+ (even better with 8.1+).

Bitrate depends a lot on the source quality. You can get away with 4Mbps for full D1 if the source is clean (especially with NTSC movies), but for most TV tuner content, I use 6Mbps for full D1.

lordsmurfhas pretty good guides relating to real-time MPEG captures. I do most of my encoding from the tuner at 352x480 @ 3-4Mbps.

[lordsmurf]

Yes it works and yes it's often better.

Now how it works often eludes me... I believe it has something to do with cache and other functions of the chips ... I do know that VBR capture only seems to work well on DVD recorders and ATI AIW cards.

[MrMungus]

Yes it works and yes it's often better.

Now how it works often eludes me... I believe it has something to do with cache and other functions of the chips ... I do know that VBR capture only seems to work well on DVD recorders and ATI AIW cards.

Well, maybe that's why there's a delay built into (some) cards like the PVR-250 which is 1 to 2 seconds off from live...