checkout different layer

[Guest]

     hi,everyone!

     I'm now facing a problem about checkout different layer data. I have read the example project "checkout",and I can get frames of a video in different time using PF_CHECKOUT_PARAM. In this example, I also see a function PF_CheckoutLayerChannel which can get the data PF_ChannelChunk chunk, but I know little of PF_ChannelChunk from the After_Effects_SDK_Guide, so as the datatype PF_ChannelRef and PF_ChannelDesc. What I want to do is input two different videos in AE and get the correspondding frames of them seperately, How can I do it ?

     Any suggestions are welcome!

     Thank you!

[Guest]

Well,maybe this question is too wide.So could anyone please tell me whether I'm on the right way? using  PF_CheckoutLayerChannel to get get the corresponding frames of two input videos seperately?

Any suggestions will be highly appreciate!

Thank you!

[Guest]

hi,everyone,The problem can be described like this, I have two videos in my timeline window, but when I use PF_CHECKOUT_PARAM, I can only get the data of first video which is shown in the composition window, How can I checkout the second layer,I was stuck several days,could anybody help me? any suggestion will be highly appreciate!!!

[françois leroy]

Hi,

I might be wrong, but I think you need to use a Layer parameter, then checkout this parameter.

Or did I misunderstood the problem?

Cheers,

François

[Guest]

Hi,François

     Thanks for your reply!

     Yes, I do use a Layer parameter, but in the user guide, it devoted that maybe I can only checkout the current layer, that means that I can only checkout the layer which index is "1" in the timeline window? How to find a way to checkout the layer under the current layer? or can I choose a layer to be current layer?

Cheers,

Heng

[françois leroy]

Hi Heng,

let me explain in details. You probably don't need that much info, but it'll help finding the error:

1_In ParamsSetup, you have something like this:

AEFX_CLR_STRUCT(def);

PF_ADD_LAYER("Source", 0, SOURCE);

It means that when your effect is applied to a layer, you can choose any layer (including yours) in the composition with this parameter.

2_In your render function you have:

PF_ParamDef		check;
		AEFX_CLR_STRUCT(check);

		ERR(PF_CHECKOUT_PARAM(  in_data,
								SOURCE,
								in_data->current_time,
								in_data->time_step,
								in_data->time_scale,
								&check));

now, you can access the layer's pixels using check.u.ld

When you're done with your pixels, don't forget to checkin:

ERR2(PF_CHECKIN_PARAM(	in_data,
								&check));

Hope it helps,

François

[Guest]

Hi,François

      It's so kind of you to answer my question! well, it dose work!

     And I still have another question.that can we change the default state of the layer added by PF_ADD_LAYER

     since we use PF_ADD_LAYER("Source", 0, SOURCE); to add a layer which id is SOURCE,and we set its default content as PF_LayerDefault_NONE,  another default state is PF_LayerDefault_MYSELF, can we set the default to a specific layer?  which means after we first apply the effect, in effect control window, it will not show like this

but will show like this

the "left1.avi" is a specific layer added by customer.

forgive my poor English, Thank you again!

[Guest]

And I think if I can get the value of this slide bar, that also works. There is a little introduction of PF_ADD_LAYER in user guide ,How can I find more information, I always feel so guilty to waste so much time of you to answer my question.

[françois leroy · Accepted solution]

Hi again,

I think you can try to change the default value in your case PF_ADD_LAYER("Source", 2, SOURCE);

I've never tried, so you'll have to... But it should work, if and only if you have at least 2 layers in your comp. And there is no way that I know to check how many layers you have when you apply the effect...

But definitely, prefer PF_ADD_LAYER to PF_ADD_SLIDER. A layer parameter is automatically updated by AE when you change layer's index, add a layer, etc... Also, it only shows "selectable layers", it means for example you won't get cameras or lights as they don't have pixels associated.

Hope it helps,

François

[Guest]

Thanks a lot, francois! your reply help me a lot! It dose work!