HDTV Gray Bars

Here you can ask your questions on how to use Comskip for the detection of commercials. Also questions on how to remove commercials are welcome
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psionic
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Joined: Tue Oct 31, 2006 12:25 am

HDTV Gray Bars

Post by psionic »

A local CBS station broadcasts 1080i continuously. Instead of changing aspect ratios for non HD commercials, they upscale it and put gray bars on the sides. Unfortunately they leave these bars up throughout the commercial break and they don't fade between commercials.

Is there a way that I can configure ComSkip to ignore these bars, or use them as a commercial indicator?

erik
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Post by erik »

Could you mail me a .csv file created with output_framearray=1 and a file listing the start and stop frame numbers of the commercials?

I will have a look if there are others clues in the broadcast

psionic
Posts: 9
Joined: Tue Oct 31, 2006 12:25 am

Post by psionic »

erik wrote:Could you mail me a .csv file created with output_framearray=1 and a file listing the start and stop frame numbers of the commercials?

I will have a look if there are others clues in the broadcast
I just sent you an email with a .zip as described in the sticky thread.

erik
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Joined: Sun Aug 21, 2005 3:49 pm

Post by erik »

A very interesting example indeed. Almost no black frames.
When there are no black frames you MUST enable the detection based on silence.
I made the following changes

detect_method=111 ; to enable silence detection
max_volume=200 ; automatic volume did not work (will have to look into that) so manual setting
min_silence=7 ; reduced min silence to make detection more agressive

There is still one small error of some seconds, hope you can live with that
:)

psionic
Posts: 9
Joined: Tue Oct 31, 2006 12:25 am

Post by psionic »

erik wrote:A very interesting example indeed. Almost no black frames.
When there are no black frames you MUST enable the detection based on silence.
I made the following changes

detect_method=111 ; to enable silence detection
max_volume=200 ; automatic volume did not work (will have to look into that) so manual setting
min_silence=7 ; reduced min silence to make detection more agressive

There is still one small error of some seconds, hope you can live with that
:)
Thank you very much for your help.

I'm writing a letter to my local TV station about those damned gray bars ... I guess they're trying to let everybody know that they are broadcasting widescreen ... but they make 4:3 content look like crap!

erik
Site Admin
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Joined: Sun Aug 21, 2005 3:49 pm

Post by erik »

I am considering a ignore_sidebars option to solve this problem......

psionic
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Joined: Tue Oct 31, 2006 12:25 am

Post by psionic »

erik wrote:I am considering a ignore_sidebars option to solve this problem......
I would like that option... the .csv I sent in had the national commercial breaks already cut out of it (the ones without the sidebars)... now that I've had time to run a few full length shows through it, its a little hit-or-miss.

erik
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Joined: Sun Aug 21, 2005 3:49 pm

Post by erik »

I uploaded build 61.
Could you test this?

From the changelog

Changes in 0.79.61
- Added parameter for ignoring gray side bars, set ignore_side=number of pixels to ignore, check visual in debugwindow
- Bug solved: Long commercials are not recognized on 60fps HD recordings

psionic
Posts: 9
Joined: Tue Oct 31, 2006 12:25 am

Post by psionic »

erik wrote:I uploaded build 61.
Could you test this?

From the changelog

Changes in 0.79.61
- Added parameter for ignoring gray side bars, set ignore_side=number of pixels to ignore, check visual in debugwindow
- Bug solved: Long commercials are not recognized on 60fps HD recordings
I just dialed it in with ignore_side=240 (figuring 4:3 content with height=1080).

I'll run it tonight against a show with content in 16:9 and commercials in 4:3.

Thanks!

erik
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Post by erik »

And?
Did it work?

psionic
Posts: 9
Joined: Tue Oct 31, 2006 12:25 am

Post by psionic »

erik wrote:And?
Did it work?
Sorry for the delay in my reply...

I've been trying to tweak it ... but I still can't get it even with the ignore_sidebars. With the ignore_sidebars enabled, I can't use logo detection, since the network's logo is within the sidebar region during the show.

I turned on ignore_sidebars, and only chose silence and black frame detection but it was still a miss.

Can ignore_sidebars be changed to something like detect_sidebars? Basically if there is a solid color in the detect_sidebars region, the scene is treated as if it were 4:3 content. I could then scan just for aspect ratio change.

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