lost bright capturing with IEEE 1394

[poncho]

Hi..

I capture video with IEEE 1394 PCI Card.....(from mini DV...Sony DCRTV 22)....

I notice two things....

when I capture to AVI direct... I have images freeze sometimes.....
Ok ..so I decide capture with mpeg quality DVD....
The continuity of video is good...but I notice ,the bright and color of video is not the same like in the original video , its "little low"...(actually is in the same way its looks in the preview window of the capture software)..

Any Idea what could be happening..

I probe with some several softwares ,with same results (Ulead Video studio 7, pinnacle studio, DVD moviefactory.....)

[poncho]

Could be the generic card Im using?

[Donny661]

What type/amount of memory, processor, and hard drive space do you have? (It would really help if you filled out the "computer details" section of your personal profile so we wouldn't need to ask every time )

If your computer is too slow, it may not be able to decode all the information in the avi fast enough. Make sure you don't have too many programs running when capturing or playing back video. If too many programs are running when you capture you may be experiencing "dropped frames". That happens when the computer isn't able to put all the frames on the hard drive at the same rate it receives frames from the firewire interface. Jerky video playback is usually a sign of dropped frames. Also, try defragmenting your hard drive before capturing. It slows down performance when the computer has to search everywhere on your hard drive to find the pieces of the video file.

The bad colors may be a result of capturing to mpeg "on the fly". This method does not produce as good results as you would find by encoding after capturing to avi. MPEG is more compressed than DV which means the software has to make a descision between quality and speed, and, in this case, you are forcing it to choose speed.

It could be the card you are using, but I would think the other possibilities I have already suggested would be more likely. If you want to be sure, try borrowing a friend's card, or take it to their home to capture there.

[poncho]

Thanks a lot for answer me...And sorry for forget the important data you question me

This is the data of PC

Pentium IV 1.7 GHz
Memory 376 MB RIMMS 400 MHz
The HD is one 40GB (I thinks is 5400rpm,could be this the problem? )
and I use a partition for save the video of 10GB (NTFS)

About the programs...I did..... I close Every thing I found doesnt need (Antivirus,etc)
By the way the preview in the capture software is "low colour" too,is llike "green" , no has is in the display of the camera.....

Any idea?

Thanks by advanced

[redwudz]

What program are you using to transfer DV to your computer? Generally, I use WinDV or DVIO for transfer to HD from a DV camera. Check the DV quality at that point. I use TMPGEnc to encode to DVD format then, and TMPGEnc DVD Author to author for DVD. If you 'capture' in DV, HD speed is not usually a problem. For DV, your video card is really not that important.

[poncho]

I use Ulead Video Studio 7....for transfer the video (DV 2) from Camcorder to HD...

[upshot]

The IRE BLACK setting for your DV is 0 whereas when you output it (I assume to your TV??) it expects IRE 7.5

Therefor your video looks dark... You need to find a way to get your DV upto IRE 7.5....

I'm no expert... I just read about the DV 0 thing last night...

[donpedro]

...but I notice ,the bright and color of video is not the same like in the original video , its "little low"...(actually is in the same way its looks in the preview window of the capture software)..

Any Idea what could be happening..

There was a graet post here (I believe I replied to it) with link to site that describes that problem with an explanation why. Right now I am lazy to search but you can try to find it ....

[upshot]

http://www.signvideo.com/dv-black-level-dvd-7.5-ire-0-ntsc-part-2.htm

here is what I read... But maybe it does not apply??

[donpedro]

I think it's pointing to same article.....
https://www.videohelp.com/forum/viewtopic.php?t=202340
or little discussion here
https://www.videohelp.com/forum/viewtopic.php?p=791425&highlight=black+level#791425

[poncho]

Thanks upshot.......I already read it ....

I understand why looks dark in my PC the video from DV......but I still have the question on my mind...wil be the DVD create from an AVI of DV in the same quality (of course that is afected for the encoder, but Im talking about "bright" and color)

[trevlac]

I'm sorry if this is covered in one of those threads/articals, but I did not read them all.

Digital Black

DV follows a digital spec that sets black as 16 on a scale of 0-255. If you do a digital copy (firewire), a recorded 16 will be transfered to your PC as 16.

When you view DV on your PC, it is converted to RGB. This conversion is likely to be done by the DV codec on your machine. This codec may change black from 16 to 0. The PC standard is to have black as 0 on a scale of 0-255. Some codecs do not change the black from 16 to 0. In this case, black will look grey.

When you encode to MPEG, the encoder probably expects RGB. Again, the DV codec converts to RGB and may (or may not) change the value of black. There are settings in encoders to tell them what you are giving them. BTW: An mpeg encoder will set black to 16 on a scale of 0-255. MPEG follows the same standard as DV.

Analog Black

An analog signal has a specific setting for black. For US NTSC, it is IRE 7.5. For NTSC-J and PAL, it is 0. When an analog signal is digitized, the black level needs to be known so it can be set to the proper digital value. (For Digital, black is the same for NTSC and PAL. There are just some possible PC differences.). An analog capture device has to know the standard, so it can set back correctly.

When a DVD player or DV cam outputs a signal, it has to set the proper analog value for black. The XBOX is said to output black as IRE 0. US machines should output black as IRE 7.5.

So... this is an analog thing. If you are not using analog output to judge the black level of your source, this does not apply. If you are, you need to measure your cam.

Things to know

Viewing on a PC vs a TV is different. Color saturation and the midtone brightness of a picture can be very different. It is best to run a sample thru your entier process DV->DVD and play it on your TV to know your output.

You can see the levels of video on a PC by looking at a histogram or waveform monitor. This would be the best way to set the levels. If your cam produces color bars, you could follow them thru your process.

[poncho]

Thanks trvlac.............

Im going to do exactly that You recommende.....

Now Im at work , later I will try ......I was going to do something yesterday but my camcorder was "low battery"......

I will give results until tomorrow......

Thanks a lot

[upshot]

Exactly! what he said!

Excellent sumation...

[poncho]

ok....

This is what i get from the test...

I capture from camcordder with...

DVIO
Ulead video studio 7
Ulead DVD work

First DVIO

I capture DV-2
I lost a lot of frames....and the quality dosnt look good....

Ulead video studio

I capture in AVI....
Quality is good but the video freeze every moment......lost a lot of frames

I capture mpeg2 3000 bitrate
Quality "not good" ,well not as in the AVI captured video....but not freeze, the video is continuos...


I capture with Ulead DVD work
I try just DVD high quality,( because when I capture in AVI the video freeze , even the quality is good), the quality is "not good" but the video is continuos.....

Well Im going to open a new post for this....

About this post....

Once i play the video in the DVD home....the bright and the colors looks "good" even the quality is "not good"......but I think thats for encode and capture....

So..
You dont lose bright and color at the end (DV to DVD)....even if the preview in the computer is darker.....

[andie41]

Nice explanation trevlac.

I didn't see if poncho was using Pal or NTSC, but for NTSC, the video will look darker, and hence the colors somewhat distorted, when viewed on the computer and out of the firewire back through the camera to the TV., as compared to the final DVD played in the standalone DVD player.

The website linked in earlier posts is what got me started sorting this out. My Sony camera records and outputs analog with black at 7.5 IRE. When this is transferred by firewire to a DV AVI, this 7.5 setup is included. If this AVI is simply converted to an MPEG (without adjustments) and burned to a DVD, the standalone DVD player will (in North America) add 7.5 IRE setup and you will now have black at 15 IRE.

If you were to adjust your TV to the brightness level coming from the DVD, the output from the computer through the camera would then appear dark and the colors off.

Of course there are numerous variables - codecs, encoders, settings, add yuv, no yuv, etc., but that can be left for another thread.

[trevlac]

When this is transferred by firewire to a DV AVI, this 7.5 setup is included.

This is not my understanding. When DV is recorded (as YCbCr), black is 16 for PAL & US NTSC. So, setup is never in DV.

Of course, you know your cam better than me. But maybe it is one of those other things you listed.

Of course there are numerous variables - codecs, encoders, settings, add yuv, no yuv, etc., but that can be left for another thread.

If your cam produces color bars, (and you are comfortable with VirtualDub), you could send them via firewire to your pc and see what you get. I made a virtualDub plugin that does a waveform chart. Here. If you need info on how to use a wfm, just post back here, and I'll give a quick run down.

[andie41]

trevlac, I had previously grabbed your VDub plugin - very nice.

My camera does not output colorbars, and I am not sure about other cameras; mine is a Digital 8. I have a hardware WFM and when I send the analog signal from my camera to the WFM, the black level indicates 7.5 IRE. When I transfer via firewire to the computer and drop the avi on an NLE timeline and send this back to the camera and out to the WFM, I still get 7.5 IRE. When I encode to MPEG and put this on the timeline and out to camera/WFM, I still show 7.5 IRE black. If I burn this mpeg to DVD and drop into my standalone DVD player and out to WFM, black is now at 15 IRE. Also, the NLE's software WFM also indicates 7.5 IRE.

Perhaps I am missing something ....

edit:

I want to be clear, I wasn't implying that the DV codec added "setup", only that my video already includes black at 7.5 and the DV codec, apparently doesn't, by default, alter this level.

[trevlac]

@andie41

Sounds like you know what you're doing. Wish I had a hw waveform monitor. I'm not sure I trust my analog capture card.

[andie41]

trevlac wrote:

Sounds like you know what you're doing.

If only that were true - just struggling along. One thing is evident - everyone needs to adjust for their own particular situation. And good luck. I do have some decent amateur equipment; if all you have is a camera and TV, it is going to be a bit more difficult.

On the possitive side, the various encoders, decoders, codecs, etc., do seem to do a pretty decent job - particularly for home productions. I doubt many of us are entering Cannes or Sundance anytime soon.

One thing I am quite certain about, and I doubt my situation is unique, my DVD player is going to adjust the black pedestal to 7.5 IRE. It took awhile to figure out whether the camera was wrong or the DVD player was wrong - they are both right. I just have to adjust my "capture" and encodes to take the DVD player into account. I suspect many either do not notice, what is a fairly small difference - 7.5%, and/or just ignore it, perhaps simply adjusting the brightness ot the TV - that is what I should do.