Codecs & Marvel's less than pro quality

[Dr Mordrid]

It's the MJPeg codec. Compression that uses direct cosine transforms, as does MJPeg, MPEG and many others, by their nature are lossy. The lower the data rate or higher the compression ratio the more lossiness. YUY2 or HuffYUV give full quality with little or no loss.

The cost is resources. You need a fast drive subsystem and at least a 500-600 mhz processor. How fast a drive depends on what the maximum resolution is you want to use.

With a single Maxtor DiamondMax Plus 40 (7,200 rpm, ATA66) you can capture up to 352x480 easily. For 704x480 captures you would need a 2-3 drive RAID0 array using a Promise Fasttrak66 or Fasttrak100 as this resolution requires 22 megs/second for straight YUY2.

Yes guys, the Fasttrak100 will be in stores soon. I have a preview board running right now. With two IBM 7,200 rpm ATA100's it posts just over 68 megs/s sequential writes in SANDRA Pro 2000.

In order to do these alternate codec captures you also need to use a capture utility other than PC-VCR as it can't use external codecs. AVI_IO is my primary choice because it can keep the audio in synch over VERY long serial captures. VirtualDUB is choice #2.

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 14 June 2000).]

[intomisery]

thanks Doc,
you da man!
that's "the man" for all you stuck at home too much.. just kidding. wouldn't mind being stuck at home doing this stuff!

Next annoying Question:
I use a RAIDO on my Media100 system at school but didn't know they could be used for PCs. How much is the general cost for say a 20gb lower model that could sustain 20Mb/sec easily?

Is VIDCAP any good for capturing (don't feel like spending money if I don't have to)?

tata!

[Dr Mordrid]

MS VidCap is OK for alternate codec capturing, it's just that AVI_IO is better. It became the standard because of it's ability to capture seamless serial files up to a total of 400 gigs without missing a beat. That's a lot of functionality for $25 USD.

The fastest single ATA66 drive right now is the Maxtor DiamondMax Plus 40 which comes in 15, 20, 30 and 40 gig sizes. It does about 19 megs/s captures, which is just below the minimums for full frame YUY2 captures. In the real world you need more like 25 megs/s in order to have some slack capacity, so for full frame captures using YUY2 a RAID controller is in order to boost the possible data rates.

A Fasttrak66 RAID controller runs $74 at buy.com. Two Maxtor DiamondMax Plus 40 drives in a 20 gig size would run $300 or less online. So, for less than $400 you can get 36-38 megs/sec capability and 40 gigs to put your video files on. Cheaper than some processor upgrades and a ton more useful.

Don't be tempted by the older Fasttrak ATA33 controller as it has a higher PCI bus utilization. Go for the FT66 or the FT100.

Dr. Mordrid



[This message has been edited by Dr Mordrid (edited 14 June 2000).]

[Walrus]

intomisery:
Well the reason I say "in theory" lossless across multiple generations is that since it stores video in YUV, any editing/processing done in RGB will require color convesions, plus the fact that YUY2 doesn't store all of the chrominance data available. The video that is captured will stay perfect, but subsequent generations may be thrown off slightly due to those concerns (though you're going to need some AMAZING number of generations to tell the difference) For capture purposes, you can think of HuffYUV as pkzipping the data that is coming into Marvel. It will give you a PERFECT recreation of what the capture board captures. Also note that VirtualDub (which can also capture unlimited video) is free. I bought a license to AVI_IO months ago, and I find I never use it, instead I just use VirtualDub.
Dr. Mordid:
I may just be lucky with this, but I usually find that with an Unraided setup I can capture full resolution HuffYUV without lost frames on my Celeron 550. (the data rates seem to average around 8MB/sec) All of my hard drives are on seperate IDE channels or a Ultra-Wide SCSI setup, and even my IBM 20 gig 5400 rpms can seem to handle the datarates fine. As long as one's CPU is up to task of compressing in real time YUY2 into HuffYUV and their hard drives can handle 12MB/sec (which a good deal can now) I don't see much point in going with RAID setups (at least for me since I don't have any spare PCI slots)

[Railie]

Walrus,
I use VirtualDub too, but how can I try this HuffYUV? What I need? Now I capture to half YUY2.

Thanks, Railie
---------------------------------------
My system: PIII-500,128MB, ABIT BE6, 2xIBM 18GB/7200rpm, W98, G200TV+RR.

[Walrus]

Railie:
Capture using the YUY2 format, and choose HuffYUV as an internal compression driver.
It's another free program (gotta love 'em!)
http://www.math.berkeley.edu/~benrg/huffyuv.html

[Dr Mordrid]

Walrus:

I prefer the RAID setups both for the pure capacity (mine is 120 gigs) and so I can do RGB full frame captures. RGB of course requires 27+ megs/sec for 640x480, which is outside the capabilities of a single drive.

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 14 June 2000).]

[cjyo~]

I have one 40gb Diamond Max plus and am thinking about picking up another and doing a RAID setup. Has anyone ever hear of these problems:

>The drives worked perfectly with the controller for about 2 weeks. They blazed through all the tests and didn't give me a single problem until a few mornings ago. To make a long story short, the Promise FastTrack RAID card does NOT get along well with the DiamondMAX series of drives (or the Quantum LM's from what I have heard).
http://www.3dalpha.com/?filename=rev...p40.txt#Maxtor

------------------
Please visit http://spincycle.n3.net - My System: Celeron 300a(@450/2v),Abit BH6, 128mb RAM, Win98SE, Marvel G200TV, Diamond MX300, Maxtor DiamondMax Plus 20g system drive, DiamondMax Plus 40 capture drive, IBM 8g Deskstar program drive, Adaptec 2940UW SCSI, 9gb Barracuda UWSCSI video drive, Hitachi GD-2500 DVD-Rom, UltraPlex CD-Rom, Plexwriter CD-recorder, Viewsonic PT775, Soundworks 4.1 speakers

[Spielberg]

Walrus,

I'm also using an 'unraided' setup, and the average data rate for full resolution captures is just a little below 10 MB/sec. I guess my data rate is higher because I'm capturing 704*576 versus your 704*480.

Anyway, the combination of a PentiumIII at 500 Mhz and my IBM 7200rpm UDMA66 drive is enough to capture full resolution without any dropped frames.

Dr. Mordrid, why do you prefer capturing RGB instead of YUY2? I'm asking this since I thought YUV is the native format for both capturing and MPEG-encoding? So there must be another reason why you do it.

Spielberg

[Walrus]

Dr. Mordid: I too am confused as Spielberg is. YUY2 is what the Marvel's internal RGB and MJPEG codecs compress from. In theory, the image quality is worse with 24 bit RGB compared to HuffYUV due to color conversion round-off errors.
However, it's hard to deny the niceness of making multiple drives act as one.
Incidently, the new IBM 75 giggers should be able to support 30 mb/sec (at least near the start of the drive) on their own.
Spielberg:
The data rates seem to vary based on the complexity of the image, so I'm sure under certain circumstances I will hit simular data rates.

[Railie]

Walrus
Thanks a lot. I download them(HuffYUV v1.3)an I try it immediately when I can(probably on the night).
May I ask additional question? It is possible play this compressed HuffYUV video on full TV-out?

Thanks, Railie.
------------------------------------
Sorry for my ENGLISH

[Dr Mordrid]

Cjyo~;

Right now I have 5 systems using Fasttrak/Fasttrak66 RAID controllers and either DiamondMax, DiamondMax Plus or DiamondMax Plus 40 drives and they're rock solid.

Very often when you see comments like the one you quoted it's a BIOS issue, IRQ conflict or just the occaisional bad drive. EVERYONE makes a few of those.

Dr. Mordrid

[Joxx]

I have read a lot on the forum but I can't really get a grip.

YUY is the native format and better than RGB? To use YUY on my marvel G400, I need a YUY crack? Where can I get that crack?

Huffyuv v1.3 compresses the file, but it is still in YUY format? mpeg encoders will work faster and give better quality if I use YUY format? because YUY is mpeg's native format?

please help me out with these questions.

[intomisery]

Walrus:
>Capture using the YUY2 format, and choose HuffYUV as an internal compression driver.

huh? I thought HuffYUV was the codec.. whats YUY2? if I download HuffYUV do I still need this YUY2 format thing?
internal compression driver?

see ya

[Dr Mordrid]

Ok...here's alternate codec capturing 101:

1. You need a capture proggie capable of it. PC-VCR isn't it. AVI_IO, MS VidCap, Ulead VCapture (comes with MSPro) or VirtualDUB work fine.

2. YUY2 is a fourCC (four charcter code) that represents a flavor of YUV, the raw video signal provided by the capture hardware. There are many flavors including YV12, UYVY and others.

Under normal conditions the YUY2 signal would be encoded by the capture cards internal codec (ex: the Marvels Zoran MJpeg), but then we aren't discussing "normal use" are we? ;-)

3. Capturing to HuffYUV, PICVIdeo MJPeg, DivX MPEG-4 or the other alternate codecs is done by redirecting the YUY2 signal to the new compressor (HuffYUV etc.) instead of using the built-in one. This compressor is best chosen in the capture programs setups AFTER choosing YUY2 capture mode.

A relatively fast processor is essential if full frame video is to be captured or played back.

4. Most alternate codecs also have their own quality settings which must also be set up.

5. Most of the codecs can also be used in MSPro or other codec aware editors. The video can also be output in whatever other codec is installed on the system, depending on your requirements.

6. There isn't really a distinction between RGB and YUV/YUY2 in terms of quality. A signal can be cross converted between them mathematically.

The details for a specific flavor of YUV or RGB will differ but the basic concepts are the same. As an example the details for the YUV12 to RGB conversion are on Intels MMX developer site;

http://developer.intel.com/drg/mmx/A...COLORCON.HTM#1

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 14 June 2000).]