Analog Capture Dropped Frames

klaatu schrieb am 22.05.2003 um 23:22 Uhr

HI ALL,

I'm new to this forum and to vegas video. A little background....

I have been in broadcast video for over 9 years, and worked on computers for 22 years. I currently run a 1.5 terrabyte SAN for a school district with over 10,000 users spread over 11 different buildings. I have been studying Digital artifacts, formats, and compression for over 2 years.

My setup.......

I've just constructed a new server using an ASUS A7N8X Deluxe MB w/NVIDIA onboard 6.1 channel audio, an AMD 2800+ CPU, 512 Meg of Matched CORSAIR Memory, Windows XP Pro, and a RAID 5 array using a HIGHPOINT ROCKETRAID 404 Controller and ( 3 ) Wetern Digital WD2000JB Hard drives ( The fastest IDE drives w/8 Meg Cache that money can buy....200 Gig Each Drive......400 Gig Useable storage after being configured. ), the main Hard drive is a Western Digital WD600JB ( 60 Gig w/8 Meg cache ), and an ATI All-In-Wonder 7500 w/64 Meg DDR Memory on board, along with all the lastest Windows updates and ATI drivers ( as of 1 week ago ), and an Intel Pro 1000-MT NIC. This system Screams !!!!!! I currently have installed the DEMO Version of Vegas Video 4.0c, DVD Architect 1.0c, am running Direct-X v9.0a and Windows Media Player v9.0.

My Problem......

I am capturing analog video from a CANNON L2 Pro HI-8 unit using the ATI's "Rage Theater Capture Driver" thru the S-Video input of the ATI Card. While I've never used a Sonic Foundry product before, I must say that compared to A/B Roll systems and Adobe Premiere 6.0 with a Matrox RT-2500, this product was Spectacular to say the least, not to mention the fact that it makes editing with premiere feel like I'm using a child's toy. Anyway, I used the premade setting of NTSC 720x480 @ 29.97 fps for my capturing, and started to record the video......the quality was PERFECT, however, I had well over 100 dropped frames, and it said my capture rate was only around 1.38 Meg a second !!!! I thought that this seemed very low for 720x480 at that frame rate. My goal is to record at 720x480 @ 29.97 fps, add some basic dissolves and titleing, and output it thru RGB/COMPONENT to a DVD Recorder at around 9.8 Meg per Second to get the best quality that I can achieve. My problem was not only that I'd dropped over 100 frames, but that the audio started to echo after about 1 minute of capture time. During playback on the preview monitor the video looked perfect, but blacked-out and Stuttered alot. Does anyone have any suggestions on how to correct this ????? THANKS !!!!! ----- BRIAN -----

Kommentare

Chienworks schrieb am 23.05.2003 um 01:38 Uhr

Get a better capture card.

As much as i like ATI for my video display card, they're just not ready for prime time capturing.

Lots of us in this forum use an external converter of some sort that converts analog A/V to DV and capture through firewire. True, DV is 4:1:1 compressed, but the quality is probably at least as good as using a low end analog capture card and the reliablity will be much better (probably no dropped frames or sync problems ... ever). Most of these converters are in the sub $300 range. The Canopus ADVC-100 is probably the most popular.

If you want to stay in the uncompressed component realm then expect to pay a lot more for a capture device.

mikkie schrieb am 23.05.2003 um 15:19 Uhr

No offense or anything, playing Devil's advocate here...

There's actually little wrong with capturing analog from an ATI card - some might even consider it a bit better in some ways comparred to a DV conversion box, like you keep all the colors by staying in 4:2:2 scan format etc... & HUFFYUV is a lossless codec that really works well. It's a bit more work, no question, but there's a LOT of folks still doing it with a lot of info available on the web.

You will have some prob. capturing if you use a VFW based app, unless you rename your folder housing the ati mmc software. Use something besides the MMC software for capture unless you're just using your PC as a vcr. Some favorites include V/Dub & AVI_IO, though several others will chime in with stuff like iuvcr (which appears pretty decent). The Vegas capture setup, as most everything else you'll find in an editing pkg, is going to oriented towards DV capture, so you'll not want to use it. Vegas capture for example won't let your apply compression on capture which you absolutely need.

Alternatively: More recent aiw cards have some nice noise removal/cropping/deinterlace & sometimes IVT features you can take advantage of on capture -> might work out well enough if you captured to higher bitrate all I frame mpg2.

What you have to watch for is to either capture to a ntfs disc, or use a prog that creates seamless, segmented avi's, to either HUFFYUV or one of the fast mjpeg codecs like picvideo or morgan. Watch your audio levels, and figure that they are likely to be low and need boosting. If you drop any frames, you may have to go to an earlier driver/mmc combo -> ones released in Jan are good.

Also, you'll most likely have to make do with a 640 x 480 picture, and might have to crop off the bottom edge at least (if so, I'd recomend V/Dub to crop & resize to a mjpeg codec - possibly ivt or deinterlace as well). If you use HUFFYUV, set to force rgb. Might need to get a soundcard.

At any rate, I haven't read anything recently to indicate that the canupus box drivers handle XP Pro SP1 yet - so something to check out there at least. If you do want to pursue the canupus box, ecost.com on their timed sale page or some of the MAC oriented outlets sell it for ~$250. An alternative might be to explore a DV camcorder that can do the conversion for you with analog, and will record in DV for new proj... The new canon zl(?) trio advertise the pass-thru conversion of analog to dv, and start at I think ~$430 at ecost.com (timed sale page).

Again, no offense to the dv folks, but...

klaatu schrieb am 23.05.2003 um 21:19 Uhr

Thanks to both of you for the help !!! I'll try the HUFFYUV and other codecs and see what happens. I want to stay away completely from any conversion boxes that only sample at 4:1:1. I have to work with 4:2:2 or 4:2:0 due to the fact that my documentary may be on television, and besides that, after working in broadcast for so long, I know what a GOOD picture should look like and I strive for the best picture quality that I can achieve. After studying/testing the Mini-DV format, I've decided to stay away from it due to it only capturing 4:1:1 ( thereby losing half of its color and luminance information at about a 5:1 compression ratio !!! ). If used for a static shot ( no camera movement ) it looks perfect, but as soon as the camera catches any motion ( especially while in bright light ), the picture completely pixelates !!!! I've learned that to get good digital video you need sampling at 4:2:2 or higher in MPEG-2 or MJPEG, and a data rate of at least 4 Meg/per second which should give you a compression ratio of about 3.5:1. For Comparison, Digital Betacam SP has a compression ratio of only about 2:1. The Maximum data rate of a DVD player using MPEG-2 compression is 9.8 Meg/per second ( as used on the SUPERBIT DVD's ), the normal data rate of most current DVD's is 4 to 4.5 Meg/per second. So as long as I can achieve around a 5 Meg/per second data rate in, I'll be fine. I've decided to stick with my HI-8 and use a Farajouda line tripler/quadrupler to up the resoultion to that of HDTV ( 1080 lines ). I'll keep you posted; and thanks again !!!!

----- BRIAN -----