Software Vectorscope

[pharries]

I am trying to optomize my ADVC 300 output. Is there a cheap software based vectorsccope out there?

[guns1inger]

What editing software do you use ? Vegas, AVID and Premiere all have built-in vectorscopes and capture capability. You might be able to feed through them in realtime to calibrate.

[NoodleMaps]

I use DV Rack with my ADVC-300. You can download a trial. has a built in Waveform as well.

http://www.seriousmagic.com/dvrack.cfm

[trevlac]

I am trying to optomize my ADVC 300 output. Is there a cheap software based vectorsccope out there?

How do you optomize? Do you have a proc amp on the analog In side? Does the ADVC have settings ?

I assume you mean Analog->ADVC->DV->PC this direction for 'output'.

Thanks

[pharries]

I am using Scenalyzer to capture. it is more flexible for capture.
I did use Premiere but quit due to it crashing all the time.
I may get Vegas later with a Sony HD camera.
For now
I use
VCR to Transcoder (if needed) to ADVC 300 to firewire. NMonitor out of the back of the Canopus.
I adjust settings from within the 300 unit.
The 300 applies to much gain foer one thing!
DVrack is just too expensive for me!

[trevlac]

There is a product called VScope that is old but might work (not sure).

If you are into harder to use but free, I wrote a vectorscope plugin for virtualdub .... BUT to view a live signal you'd have to use fddshow and avisynth to pipe the signal to virutaldub.

Here is some info ... but you'd have to go to doom9 to put all the piece together. I'll see if I can get it to work for me tonight. I know Avery was adding the ability to capture from DV firewire in virtualdub but I'm not sure if you can add filters.

https://www.videohelp.com/forum/viewtopic.php?t=269943&highlight=

Doing this is all a bit of a hack with a live signal. You have to be careful with a software scope and make sure you understand the path the data is following. If the DV decoding codec is not the same one you use in your editing, you are going to have a problem. Not really a big deal. You can figure it out. But not as simple as using a single package.

Using a scope (to calibrate) on an already captured test signal is certainly doable with the free stuff available. But you wouldn't want to do this all the time if you were using various sources and a proc amp.

PS: I would certainly make sure you know how a particular device is making adjustments. Analog would be best but unlikely. Digital is ok if it is at a high bit depth (before it was actually encoded to DV). If adjustments are applied to the 8-bit info, you might as well just do it in an editor.

I thought about getting DVRack myself. I think it's main value would be to make adjustments to a camera (like lighting) in the field (or a studio). You really want to adjust before you capture so you can get as much information captured as possible.

[pharries]

trevlac
I spent an hour trying to get your software to work last night.
I gave up!
as yu say it is not quie the simple solution you need for capture.
I hope you write a freestanding vectroscope!

[trevlac]

pharries,

Yeah ... it's a bit of a pain ... but here is how to do a live feed for free in a nutshell ...



Using
- VirtualVCR
- ffdshow
- my vdub scope
- avisynth script


1) Set ffdshow to decode DV as said in this thread

http://forum.doom9.org/showthread.php?t=80215&highlight=ffdshow+dv

2) Make avisynth script to use colortools as said here

http://forum.doom9.org/showthread.php?t=72634&highlight=vectorscope+avisynth

3) Change sample script to not use avisource and add a converttorgb32() at start, and a flipvertical() at end. And make sure plugin directory is where you put the vdub plugin.

4) Startup vvcr capture preview (or another directshow cap app)

5) Check avisynth config setting in ffdshow decoder and load the script

BINGO! A live scope .... not sure what the ffdshow decoder is doing with the colors ... but hey

------------------------------

That is a very condensed version ... but it does work.

If you are not familiar with the apps ... take small steps.

1) Make sure you can preview DV in the capture app
2) Setup ffdshow to decode dv and do an OSD to test you see it in the cap app.

3) Try my colortools plugin in VirtualDub using an AVI file
4) Try my colortools plugin in virtualdub using an avs script (hardest step)

5) Put the pieces together

[pharries]

Problem is I use a different capture application Scenalyzer for several reasons.
You can only have one preview window open at a time

[Wile_E]

I tried your vectorscope/waveform too, a long time ago, using it while playing captured video. For some reason, I think it is automatically keeping all the values between 0-100IRE. I never see anything out-of-range, even when I dileberately max out brightness while capturing video, and make everything white! This can't be right, so I stopped using the plugin and Vdub.

[trevlac]

@pharries,

Sure ... I understand. Frankly ... I only use avisynth and virtualdub to play around and look at things (or maybe special cases). When I work with DV I use Vegas because it is just a much cleaner process.


@Wile_E

That is a general problem with a software scope, and it's all about color spaces. It's what I was talking about knowing the data path. Here's the skinny ....

- Analog signal could go up to say 120 IRE

- When it is digitized, it is going to get adjusted down or most likely clipped by the hardware.

- When it is encoded it may get clipped more. Codecs which use YCbCr color space have headroom up to about IRE 115. Of course it depends upon what the codec does with those out of range values Black is supposed to be 16 and white 235 on a 0-255 scale.

**- (real problem point) VirutalDub [filters] require data in the RGB color space. A codec has to decode the video and then convert from YCbCr to RGB. Your codec most likely considers RGB to have 0 as black and 255 as white. So during this conversion the out of range values are clipped to 0-100 IRE. MJpeg codecs don't clip when they convert (some people consider this a bug). You can also use Avisynth to get around this. Different DV codec do different things. Some even have options.

- So the scope is just mapping values 0-255. If they are set as 0-100IRE, that is all it sees.

==================
Bottom Line - Should you have to worry about this?

Probably not. But unless a package takes total control of the process ... it's hard to hide this from the user.

I'm not really a programer. I made the scope as an exercise in learning. And it was certainly that.