capturing video onto pc

sleepwalker

ok so trying to capture stuff and get it onto pc through firewire but the quality is shockingly bad for some reason

any programs people would suggest that i could get the quality up to what it should be ?

Lump

Have a look at the Editing Programmes Sticky. If you are capturing via Firewire, you tend not to be able to adjust the quality it comes in at. As 5:1 is considered an off line quality even though it's not really. When you say its shockingly bad. Is it playing ok but really pixelated, or is it jumping around etc? Expand


John

sleepwalker

i was capturing through firewire putting together a stop motion animation for a multimedia project. the quality of the video just seemed quite grainy and a bit pixelated.

stop motion pro seemed to improve it a bit by averaging each individual frame as it went in

but for future reference what is the best way to digitize the footage into your computer ? i use avid in college and i had assumed that worked off the same basis of being through firewire as the quality is always fine there

Lump

Depending on the Avid, it may be SDI (Serial Digital Interface), more likely Firewire, and unlikely to be an analogue connection.

John

DonkeyStyle \o/

Lump wrote:

As 5:1 is considered an off line quality even though it's not really.

Quite curious about that tbh, what do these ratios mean?
Firewire capture quality is something that's píssed me off on more than one occasion... although at this stage I've put it down to using a crap consumer digi-cam.
Just plug in a PD170 and no more crap quality issues as far as I can see.

Tbh sleepwalker, you'd probably have gotten better results using a digital still camera for stop-motion... assuming of course that you can find a way to take each shot without disturbing the camera angle.

i use avid in college and i had assumed that worked off the same basis of being through firewire as the quality is always fine there

I'm not sure if I missed the answer to this, but what program did you end up using to capture this time?
If the capture quality is extremely below par, then I'd be thinking about what resolution and encoding the program was using.
Some of the more "user friendly" capture proggies will automatically encode your footage to mpeg1 or something similarly dreadfull.
If you're capturing from home and don't have any other software, I'd say try out windows movie maker, yeah it's pretty lame, but it's good for testing purposes... in the capture menu, you can use 'custom' quality and select DV.
Actually, this is a good example of software that likes to compress the shít out of your footage unless you explicitly tell it not to.

Lump

DonkeyStyle \o/ wrote:

Quite curious about that tbh, what do these ratios mean?

It means that it uses 5:1 Mpeg compression. Digi beta runs at about 270 megabits per second. That's about 1.6:1 compression.

I could go into the technical mumbo jumbo. But essentially Mpeg compression will use Jpeg compression on the First frame (Out of 4) it will then do the same to frame 4 of the 4 frame sequence. It then compares differences between frame one and frame 4 and notes the differences in, basically a spread sheet.

Jpeg compression will note similar pixels in a tv signal, and instead of noting the pixel one = black pixel 2 = black etc etc it'll note that pixel 1-600 are Black.

Hence essentially it is a loseless compression.

If you are really really interested drop me a pM and I'll go into more detail, it's good for me to talk about it, because I'm supposed to know this stuff

The Higher the compression, the less samples taken.

John

DonkeyStyle \o/

Lump wrote:

It means that it uses 5:1 Mpeg compression. Digi beta runs at about 270 megabits per second. That's about 1.6:1 compression.

Aha, so regular DV will be compressed on the hardware layer at 5:1 before it even leaves the camera? ... or something...

I could go into the technical mumbo jumbo.

It's not mumbo jumbo to me dude, I'm with you all the way here

Lump

Well essentially yes, it is compressed on the camera. So by capturing at 5:1, essentially you are not really compressing anymore, it is telling the computer what data stream to take it.

I'll post more wehn I get to work and have more time.

John

DonkeyStyle \o/

Cool.

Lump

Right, Mpeg Compression -

Mpeg 1 = Used by the computer industry, cannot be used for interlaced material.

Mpeg 2 = The system used by digital video broadcasting, which can take one or more video streams along with multiple audio and other data, to form a transport stream for one or a block of tv channels (Free View)

Mpeg 4 = A computer to computer interface which allows machines to delgate work to the display controller. It has strong connections with multi media and video conferencing.

Mpeg 7 = Under Development. It will be a data syastem to describe content of the other Mpeg Systems.

Jpeg uses a variety of different tools to compress still images. The two major tools are:

Discrete Cosine Transform: A matematical transformation which turns an amplification based signal into a frequency based signal.

Huffman Coding: An effective was of writing information which allocates short names to frequently occuring events (As described above). An eqivilent example would be morse Code.... The most common letters a and e have the shortest codes '.' and '-'.

Sampling Structures:

For DV the sampling Structure of 4:2:0 is used. (This is complicating) Anyway, for this sampling structure, 4 samples of Y (Luminance are taken) and 2 samples of Pb (y-b, (Luminance - blue) are taken. This is then repeated on alternate lines but on the second line, 4 samples of Y are taken, and 2 samples of Pr (Luminance - Red) are taken. Therefore it samples the chroma on alternate lines.

Digi Beta uses 4:2:2, hence chroma is sampled on each line.

Hope this makes sense.

John

Lump

Glad I went to all that effort


John

formatman

If you don't have anything helpful, and/or sensible to say, then don't.

John

Howitzer

Just by coincidence In-Dublin this week have an article on Sound Blaster Audigy 2 ZS Video Editor by CREATIVE.
For €289 it looks pretty good. http://www.creative.com/products/product.asp?category=1&subcategory=204&product=11226
It has a dv 4pin port. Would be interested in your views on this. Looks good.