Capturing live video to Mpeg4

[SeeMoreDigital]

Given that PC's are getting faster and software is getting better, I'm interested to learn how successfully some of you are at being able to capture live video, from say a VCR or TV tuner card, USB camera, etc.

I only ask because a few days ago while playing with a cheapo digital "stills" camera. I thought I'd see how well it would fair as a "internet" camera.

Anyway, somewhere along the way I got side-tracked and found myself using MediaPlayer Classic's "video capture device" to capture video.

I have to admit I was quite surprised how good the images looked from a 640x480 / 30fps capture, using XviD at 4000Kbps!

Well enough about me. What success have some of you guys had?


Cheers

[JoeShrubbery]

Back in the spring about half a year ago I switched from capping with mjpeg to instead using high bitrate mpeg4 (via ffdshow). At i-frame only constant quant 1 I find more detail preserved at comparable bitrates in mpeg4 than I was getting with mjpeg, albeit only via subjective observation. I know half the chroma information is thrown out when capping into mpeg4 (in the yv12 colourspace) as opposed to mjpeg (in the yuy2 colourspace), but since I do all my subsequent filtering and compression using yv12 anyway I don't think I'm losing much that wouldn't be thrown out sooner or later, and to me as a capture format I've been more happy with it than I ever was with any of the various mjpeg codecs I've used over the years. On anything I <i>really</i> want to make sure everything is at absolute tip-top quality on, I switch over to a lossless codec for that particular project, but for daily usage on regular content capped from cable TV, mpeg4 is where it's at in my books.

[SeeMoreDigital]

Hi Joe,

What Mpeg4 pixel frame sizes did you capture to?


Cheers

[neo75903]

Hi,

i have two capture methods for my tv programs:
- using a VCR and Pinnacle Studio AV/DV Capture card, which gives the best quality, at 720x576, so far. I have tried several TV cards for pc, but quality wise, none of them can beat an VCR. TV cards are also more picky about the quality of the cable signal.
Captured files are huge because the used DV codec, the card does not provide hardware encoding and studio only allows this DV codec.

screenshot taken with this method resized to 512*384 with XVID Simple Level@L3 at 500kbps:

http://users.telenet.be/bugged/snap Friends.jpg

- currently for lower quality capture, I use an MSI TV@anywhere tv card in combination of ChrisTV, at 1500Kbps using XVID or 3IVX single pass. It gives good quality but my pc, a dual AMD2000+, is practical not usable without causing frames to drop.
Latest version of ChrisTV also supports MPEG encoding at 352x288. The quality is still better then the final format for archieving anyway and the pc is still usable for other things.
--------------------------------------
MPEG Format : MPEG 2 DVD

Frame Size : 352x288
Frame Rate : 25,00fps
Sample Rate : 48 kHz
Video Bitrate : 1800 KBits/s
Audio Bitrate : 224 KBits/s

Total Bitrate : 2024 KBits/s
File Split : 4063 MB
--------------------------------------
a screenshot:
http://users.telenet.be/bugged/snap MTV.jpg

I like this format more because it contains less artifacts.
An AVI file sometimes gets out of sync as well.

[JoeShrubbery]

Originally posted by SeeMoreDigital
Hi Joe,

What Mpeg4 pixel frame sizes did you capture to?


Cheers

Well it depends on what I'm targetting it for. Most stuff I'm capping nowadays I reencode to mpeg2 and author to DVD, so it's either 720x480 for content coming straight from the broadcast or 352x480 for anything I'm converting from VHS (I'm a Canuck in NTSC-land if you haven't guessed yet).

Keep in mind, I'm using a generic BT848a based capture card on a system running with an AthlonXP 2500+, overclocked somewhat, a half-gig of RAM, and 100gigs of free hard drive space to play with, but before some recent upgrades I was using a 1.3ghz Duron with only half a much RAM and still able to capture at full D1 no problem (although I didn't quite have the CPU muscle to pump it at constant quant 1, had to work with 2 which meant slightly less detail preserved in my captures)

BTW, I do use an external VCR for tuning in stations. The signal I get from my VCR has less interference than my card's internal cable tuner offers up, and there's a lot to be said about being able to just kick back and flip channels with a remote instead of a keyboard :'>

[neo75903]

yeah the old vcr is just like avi, just refuses to die :)
And if you have the cash read this:
http://www.pcworld.com/news/article/0,aid,118050,00.asp

and much cheaper, Sony is already selling HD based VCRs which i dont understand why they arent selling it in the rest of the World.
http://www.sony.jp/products/Consumer/cocoon/CSV-EX11/
these are beautiful babies ofcoz for that amount of money someone can just make their own pc. But the cocoon also has stront points:
- fail free, dont get suprises when you come home and your pc has crashed or recorded file is corrupted. It did happen to me a few times, specially when one of those sheduled (anivirus for example) kicked in during a record or something elses causes dropped frames.
- uses less power then a full blown pc
- less heat
- dummy proof, coz just like and old skool vcr just press those Rec buttons. Not that i am a dummy, i guess, but sometimes things have to go fast and you just dont want to worry about settings.


look at this:
http://www.snapstream.com/Community/Articles/medusa/default.asp
Maybe the way to go for an home centric tv recording solution?

@seemoredigital:
got your ubs.mov from your website, awesome quality, can i have your settings? is it comparable to XVID's Simple Level 3?
It played really nice even without 3ivx installed.

[scharfis_brain]

How do you all avoid the interlaced-YV12-chroma problem?

capping with interlaced XVid?

[neo75903]

i have thought about this issue as well when i started. But strange enough i never encoutered this as a problem on both of my solutions.
I presume that my Pinnacle board has some hardware to resolve this.
But my MSI neither has a problem with that. See my screenshots above.
I have nowhere an de-interlaced filter switched on.
Only when i change my reolution (in ChrisTV) to a not native resolution it appears a bit but never as much as i have seen by other ppl.
It would be nice if someone can explain to me why... the x-files continues :)

edit: now i remember, i had one of the first hauppage PVR card before and the pictures where horrible. lot of noises and interlacing was an disaster. Has anyone experiences with the newer hauppage pvr 250? Kinda interested after reading the snapstream's medusa project.

[JoeShrubbery]

Originally posted by neo75903
yeah the old vcr is just like avi, just refuses to die :)
And if you have the cash read this:
http://www.pcworld.com/news/article/0,aid,118050,00.asp


Ah, hardware I won't be able to afford any time soon ;'>
Personally if I had the cash I'd say to hell with waiting for this fancy stuff to come over across the Pacific and just grab something available to me right now, that being either a D-VHS VCR or a standalone DVD recorder. Personally I'd lean towards the D-VHS: while currently the more expensive solution (at least around here), it's got all the bells and whistles necessary to make everything look as nice as it possibly can, and with the right software it's trivial to transfer over the transport stream from tape to PC via firewire. Plus, you can record for a hell of a lot longer at max bitrates on D-VHS than you can on a DVD. ;'>