Video Capture G400 vs. G450eTV

[Labrat]

I have a Marvel G400-TV setup, and I have a friend who wants to get into video capture & editing, and he is trying to decide which card to use. I am trying to figure out how good the video capturing is on the G450eTV, and I can't find any info on Matrox's website. How does the G450eTV compare to the Marvel G400-TV? Does the G450 use MJPEG? Can you do the same types of capturing on the G450eTV as the Marvel G400-TV?

Now, to complicate things a little more, my friend has access to a Rainbow Runner G-Series, and he would like to possibly pair that with Millennium G450, but from what I can tell at Matrox's website, you can't use a RR G-series with a Millennium G450. So, what are the best options? Thanks.

[Dr Mordrid]

The G450 can use a software MJPeg codec like PICVideo (my favorite) with a capture program like AVI_IO. PICVideo also can be set up for much higher max. data rates than Matrox's MJPeg codec.

Nice extra: PICVideo is a VERY fast codec, so full frame doesn't need much more than 600mhz or so. Not bad for a software compressor.

PicVideo MJPeg is $18 here;

http://www.jpg.com/video/mjpeg.htm

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 19 May 2001).]

[This_Idiot]

Doc, what you said was valid, but didn't actually answer the original question

The G400 Marvel uses hardware MJPEG for capture, although (as plenty of people here have discovered), it can be "persuaded" to capture in YUY mode and then a 3rd party software codec used to encode into a suitable format on the fly. This takes a reasonably heft processor, although not anything unusual by todays standards. I think that we settled on anything North of a 600Mhz should be able to do this (Anyone confirm ?). This capture mode is only available using hacked drivers, and isn't supported by Matrox. TO be honest, none of us are sure why Matrox haven't acknowledged the feature, since it's a real bonus and seems to work pretty well.

The G450eTV doesn't have any hardware compression at all, and (by default) uses a software MPEG2 compressor which needs upwards of a 933Mhz processor in order to turn in full frame capture. It also has a lot of trick features not available on the earlier Marvels such as time-shifting which are really neat. I've not really dug deep into all the permutations yet, but I'm sure that I've heard that the eTV can also use the YUY method. Doc will certainly know (in detail) !

Chris
(T_I)

[Dr Mordrid]

I thought by stating that the eTV can be used to capture with PICVideo YUY2 was present by implication. Ok...for the record;

YUY2 is fully active in the eTV drivers. No hack necessary.

And yes TI...CPU's north of 600mhz (700+ is best) should be enough for YUY2 related activities. For the eTV's built-in MPEG-2 you will need a 933 though...minimum. On a system with a not so hot mainboard more may be necessary.

The only capture option it's missing is built-in hardware MJPeg, but this is a trivial issue. By using PICVideo you can capture at higher data rates than the old Zoran chipset could handle. Most sources at Q=20 deliver 5-7 mb/s, almost double what the old Marvel G400 drivers could manage. While this means larger files it also means higher quality.

The difference hardware wise is that the eTV has no BOB. It uses a cable spider at the back of the system. IMHO this can be better than a BOB since there is no wrist-thick cable to play with. Since most of my connections are permanent (save for S-Video & audio inputs) this works better for me.

Another change is that the TV tuner is on the board and not in the BOB (which is gone anyhow) and that the board is MUCH simpler. The G450 integrated a lot of circuitry that used to be on the PCB with the G400. That eTV is SMALL.

Using AVI_IO, VirtualDUB etc. as the capture utility you can capture using the YUY2 format to alternate compressors of your choice. This can be PICVideo MJPeg, HuffYUV, DivX, Morgan MJPeg or even MPEG-1/2 using the VideoStudio 4/5 or MSPro 6 capture modules.

The latter two are of course problematic at this point for quality reasons if your intent is sending the result to videotape, VCD or SVCD. This is due to the faulty MPEG engine Ligos dumped on Ulead. Nice guys. There are updated Ligos MPEG engines coming so this situation is temporary. The new Ligos engines produce quite nice MPEG's. Trust me

In short the eTV can do what the Marvel G400 can do, but without hacks. You do, however, have to purchase the now commercial PICVideo MJPeg or Morgan MJPeg (I prefer PICVideo). PICVideo runs all of $18 USD. STILL a steal.

I use mine strictly with AVI_IO as the capture program, ignoring PC-VCR and its built in MPEG-2 (also by Ligos). I find MPEG's produced by encoding HuffYUV much higher in quality than those produced by PC-VCR, plus PC-VCR cannot do MPEG-1.

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 21 May 2001).]

[Labrat]

Thanks a lot for all the great info. My friend just happens to be running a 933MHz, so it appears the 450eTV is the way to go, with the PicVideo.

I only have a couple of questions (I am new to this forum). What does BOB, PCB and YUY stand for?

[Dr Mordrid]

Grab your chair...here comes video 101;

BOB = the BreakOut Box

A blue box with the analog I/0 connections on it. The G400 Marvel has one, the eTV doesn't. The BOB was a good idea, but having the TV tuner in it made for a thick and inflexible cable. That made placing the BOB tricky without breaking one of the small cables inside.

PCB = Printed Circuit Board

The card itself.

YUY2 = a variant of YUV, an uncompressed video format

It's the signal the card extracts from the video inputs. In NTSC YUV is more properly called YCrCb (a difference without much of a distinction):

Y = luma = the B&W portion of the video signal. Provides most of the linear resolution. In a 704x480 frame it delivers a full 704x480 horizontal resolution.

U = Cr = chroma red = one half of the color signal.

V = Cb = chroma blue = the other half.

Unlike the luma sighal, in a 704x480 frame Cr and Cb deliver a horizontal resolution of 352x480. Chroma resolution is almost always less than luma resolution outside of a studio.

This lower resolution of the chroma signals is what gives consumer video its "colorspace", which is defined as 4:2:2. 4 for Y, 2 each for Cr and Cb.

Lowering the colorspace can have its effects. It amounts to a reduction in color resolution, which can cause or contribute to artifacts under certain conditions. 4:2:2 isn't too sensitive to this, however.

Since YUV/YUY2 are uncompressed raw signals capturing with it as the format gives the highest possible quality.

The rub: it requires a data rate of about 20 mb/s, which is hard for single drives to maintain throughout the whole drive. This is RAID array territory.

The fix: the HuffYUV codec. It losslessly compresses YUV/YUY2 by 50% on the fly during capture, taking the data rate down to about 10 mb/s. Single drives can handle this. The resulting files are perfect for encoding to MPEG's for use in VideoCD, SuperVideoCD or DVD.

Still the data rate is high enough that a 2 gig file contains only a few minutes of video. To alleviate this one uses AVI_IO to capture the video. It splits long captures into multiple 2 gig files on the fly without dropping any frames between. String them together in the editor for encoding and you're ready to edit. $25 and worth every cent.

IF the destination is videotape instead then PICVideo MJPeg is the better choice of compressors. It is capable of higher quality than the G400 Marvels Zoran chip because of its higher potential data rates.

On another related tack....

DV video (as used in a digital camcorder) uses half again the chroma resolution of YUV 4:2:2. It uses a colorspace of 4:1:1.

This delivers a horizontal resolution of only 180 (with a horizontal frame size of 720). DV may be lossless when copying it from the cam, but it ain't perfect. This is especially true when adding special effects. This is where its reduced colorspace hurts and can cause those artifacts I mentioned earlier. It can take some rather expensive compositing software (After Effects, Boris RED etc.) to fix the problem in many situations.

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 21 May 2001).]