MPEG-2 bitrate > 4000 with DVD Xpress DX2?

[miamicanes]

Is there any way to get the ADStech DVDXpress DX2 to record MPEG-2 with a bitrate higher than 4,000kbit/sec? According to the datasheet for the chipset it uses, the chip itself is capable of 10,000kbit/sec VBR. I'm guessing that ADStech's marketing department or management had the "brilliant" idea of arbitrarily limiting the bitrate to 4mbit/sec to ensure that 2 hours of captured video would fit on a 4.7-gig DVD.

I've read allusions to manually editing the registry to get it to use higher bitrates, but so far I haven't had much success. I changed m_nSelVidBitRate from "4000000" to "8000000", and changed szbitrate='4.0mbit/sec' to szbitrate='8.0mbit/sec' in the m_sCustomVideoParams key and tried capturing again, but the entire computer froze hard a little over 14 minutes into the capture. Oops. Also, the manual hints that it uses VBR, but in the 'custom' string, I noticed that vbr=0... which doesn't quite give me warm, happy feelings of comfort...

[miamicanes]

Well, I got an official response from ADStech. They said that the 4000kbit/sec statistic is an observation, not a coded limit. Apparently, in "best" quality mode they aren't actually limiting the bitrate. Rather, 4000kbit/sec is the most they've actually observed the Micronas codec chip actually USE.

I'm not 100% sure that I buy it completely, but it's not inconceivable. I've done embedded hardware/software development, and I know that the pdf brochures for quite a few large-scale chips are (cough, cough) "embellished" a bit by marketing departments who don't necessarily understand the chip itself. Case in point: pre-3D video cards whose specs might have been given as, "2048 x 1440, 32-bit, 240hz refresh" where in reality, you could never actually get 240hz refresh at anything above 800x600, and the card only had enough RAM to do 24-bit color at 1280x1024.

In any case, it's moot. I decided to spend the extra hundred bucks and buy what will hopefully be the last NTSC capture device I'll ever have to buy: a Pyro. Besides giving me total encoding freedom via software (that, at the specs provided by the DVD Xpress, could be done in near-realtime anyway), it's firewire-DV, so I'll never, ever have to screw with a proprietary capture driver again.

[redwudz]

Have you checked the encoded videos to see what their bitrate was? With VBR bitrate it may not be accurate, but may give you some info. Gspot 2.70 may be able to do that.