Determine if video is grayscale/black and white

[skribby]

Hi, is there a way to determine if a given video or list of videos are grayscale?

I've googled for a while and don't seem to come across anything relevant.

[manono]

I open them in an AviSynth script and add this to it:

ColorYUV(Analyze=True).Limiter(Show="Luma")

The '128's tell you it's been grayscaled. Any other numbers and it hasn't:

[skribby]

Would it be possible to batch output this to a text file? I don't want to have to sift through hundreds of video files in different folders manually >_<

[manono]

Beats me. I don't usually work on downloaded videos and what I do work on is one at a time.

[jagabo]

I don't know of any way of sending ColorYUV's output to a separate file. And that technique has many limitations. ColorYUV analyzes each frame individually. So a color movie that starts with a fade from black may appear to be greyscale if you only look at the first frame. Many old movies start with a new color logo and then switch to the original black and white. The chroma channels will only be 128 if the video is perfectly grayscale. Any video that's slightly sepia toned or otherwise off-white, intentionally or not, will not have perfect 128s. Then you have the occasional movie that's a mix of black and white and color (Wizard of Oz, She's Gotta Have It).

[skribby]

I found a work around, problem solved !

thanks anyway

[smrpix]

I found a work around, problem solved !

thanks anyway

Please share so others might benefit. Thanks.

[jman98]

I found a work around, problem solved !

thanks anyway

Please share so others might benefit. Thanks.

I wish we could kick jerks off the site who do crap like skribby where they refuse to tell what they did to fix it.

[skribby]

Since you want me to share, smrpix ,I'll do it. I thought it was going to sound quite obvious so that's why I was hesitant to post about it.

But anyway... I installed Icaros so I could get thumbnails for all formats/codecs, then I simply waited for the thumbnails to load and from there on it was quite easy to see which videos were greyscale and which ones weren't ;)
The actual chroma values are irrelevant in this case (since you could probably make a video "look greyscale" while still retaining a 16-bit palette or whatever).

No need to get hostile jman98. And don't put words in my mouth - I never "refused" anything ;)

[manono]

I thought it was going to sound quite obvious so that's why I was hesitant to post about it.

Not so obvious. There's a ton of videos out there that are supposed to be black and white but which really have a slightly greenish or purplish (or other color) tinge to them. I thought originally that's what you wanted to know - which had been really grayscaled. But apparently that wasn't what you were after at all. You seem to want to know which are supposed to be black and white, not the ones that really are black and white.

[skribby]

I know what you mean.

In this case I was looking for a video, I did not remember the name of it or where I had put it, but I remembered it was black and white.
Of course, looking through thumbnails you could definitely determine if you had any videos that were greyscale but had a an ugly hue instead

[jagabo]

I have many black and white movies that start with a color logo.

[skribby]

In Icaros you can change the thumbnail offset so you can essentially put a 25% offset so you can easily determine if the "actual" movie is non-color.

[El Heggunte]

In this case I was looking for a video, I did not remember the name of it or where I had put it, but I remembered it was black and white.

Typical example of *badly-defined problem*

Hi, is there a way to determine if a given video or list of videos are grayscale?

I've googled for a while and don't seem to come across anything relevant.

[skribby]

Do you want me to edit the OP or what?

[smrpix]

Do you want me to edit the OP or what?

I'm not a big fan of that in general, because it can unfairly make the people who posted answers look like morons who didn't understand the question.

But as you can see, without your goal being stated, what was obvious to you could be (and was) interpreted in many different ways.

[skribby]

What I learned from this thread was: troubleshoot more, post later. And also, to not start threads on videohelp when baked...