Compression while capture DV

[Tamango]

Hello,
I've been looking everywhere on the forum, but with no luck. Is there a software for doing DV capture while compressing?? I know the quality won't be as high, but I'm limited on harddrive. Every free program captures raw footage.
Thanks

[Richard_G]

You've got two choices, buy some software that compresses on the fly or buy a new hard drive. Personally I would think the hard drive would be the cheaper option and you wouldn't end up with any quality loss.

[gastorgrab]

Won't MainConcept encode from DV to MPEG "On The Fly"?

[edDV]

Won't MainConcept encode from DV to MPEG "On The Fly"?

Yes it will but your machine needs to be fast to realtime compress MPeg2 with a software encoder. This is especialy true for high compressions.

I can realtime compress with the Mainconcept MPeg2 (DVD) encoder in ULead Video Studio 8 at 8,000Kbps with LPCM audio with a P4 or Celeron 2.4GHz, 512MB Ram and peak CPU usage near 90%. It won't work at 6,000Kbps or with the added load of MPeg audio so I think this is a practical lower CPU limit. Adding memory did not seem to help.

This test was done from a DV stream comimg from a Canopus ADVC-100 transcoder connected to a cable tuner.

Best to use a faster processor than this for realtime MPeg2 capture to add a bit of safety margin. An alternative is to use a hardware MPeg encoder (e.g. PVR-150)

[Tamango]

Thank you for your replies, I'm bumbed out to hear that there's no compression while capturing. I guess I'll capture 10min intervals, and compress with VirtualDub.

Thanks for the fast replies

[FokeyJoe]

Heh.. what do DV people know about capture codecs?

I was having problems with this on a slower machine (1.3Ghz Athlon) that didn't seem to capture (I know I know, copy) well enough using WinDV or DVIO. I found that iuVCR was able to take the feed from the DV and use the full range of codecs. I also found that amcap could just about capture from DV, so on that basis, any capture tool that supports WDM (not VfW like virtualdub) drivers should work.

I'm still experimenting with the best setup to use. Alas, as our DV friends here suggest, most codecs require an extreme amount of proccy power, so the choices of codec are limited. Divx/Xvid/MJPEG/Cinepak/etc. all use too much proccy power for live capture. It comes down to 2 choices, huffyuv (there's a couple of spinoffs of this as well, like Alparysoft's lossless codec) or the DV Encoder (also selectable in iuVCR). In actual fact, the DV Encoder codec is okay, but you need the latest VirtualDub (currently v1.6.2) to edit the dvsd format AVI, I've not tried this yet. I'm also yet to try huffyuv (gets between 2:1-4:1 lossless compression), but it's been great for analogue capture, so I have high hopes. But also remember that iuVCR will let you change the res you capture at, so if full frame 704x576x25fps won't work, you could drop to 352x288x25fps and be more successful.

Also watch out for sound, it's not always passed on in the feed. This may also limit your codec choice.

Hope this helps... and if you choose iuVCR, please register it, it's worth it

[Raga]

But huffyuv takes an awful lot of space, doesn't it? How muhc does it take, anyway? (Gain in compression compared to DV-format.) (Alas, Google is silent.)

[FokeyJoe]

I can't comment on whether the DV Encoder codec is better than huffyuv, as I haven't been able to try them side by side. But you originally asked whether there was a tool to be able to use the codecs. - I've at least answered that for you. You're probably right, but it's very little effort to try it out yourself.

However, if you really don't mind quality loss (can't understand why) then DivX is the codec for you. The files it creates are tiny, but you'll most likely only be able to do 352x288. I think you can do 1-pass fastest with the free version of the codec. Use as high a bitrate as you can give it (that means > 1500kbps, probably > 3000kbps would be ideal). You'll notice some artefacts when the scenes change from low action to high action (and you might be able to compensate for this by tweaking the low level settings).

But really, if you're looking to capture over 40 minutes you should really really really be using a lot more disk space. I use a dedicated empty 80gb partition for analogue capture. You shouldn't need that much space, but it helps!

[edDV]

FokeyJoe,

I'm missing your point. DV transfer from the Canopus ADVC is a no brainer from any analog input.

The goal I was speaking to was realtime analog to DVD compatible MPeg2 encoding. Just cap it and burn to DVD, or edit/author/shrink if you need.

It can save hours to get to a playable DVD.

[FokeyJoe]

Tamango never asked about producing DVD output, or requiring MPEG2 compression, no mention of the Canopus ADVC, or what the capping source was, or said how much disk space was available to play with, how much proccy power there is, or how much he/she was willing to pay for a solution. Given so little information, then all possibilities can be valid. And my suggestion costs £0 or $0, so Tamango is free to try it out as a solution before looking to cost-based solutions.

There's one bit of software that might do it in one, but only if it picks up the DV capture device (I'm not sure whether it would or not), and that's NeoDVD by Mediostream. It caps straight to MPEG2, and I think it also has burner software in it's suite.

[edDV]

Well the request was for "doing DV capture while compressing?" Probably a camcorder, maybe an analog source.

Most probable default interpretation of that request from a beginner would be for the purpose of DVD MPeg2, SVCD MPeg2 or VCD MPeg1 encoding. Otherwise they would have specified a format.

I was actually responding directly to gastorgrab who asked a question about realtime capture with the Mainconcept encoder.

Your statement
"But really, if you're looking to capture over 40 minutes you should really really really be using a lot more disk space. I use a dedicated empty 80gb partition for analogue capture. You shouldn't need that much space, but it helps!"

I routinely capture up to 20Hrs of realtime MPeg2 into a 80GB partition. If the processor was faster I could get 25% more with a 6,000Kbps CBR MPeg2 capture.