TDA4VM: MSC node downscaling for the customized application

Seetharama Raju

Part Number: TDA4VM

Hello TI,

I have a working four camera application( on TDA4VM) in SDK 08.06.01.03. My pipeline is Capture node-->Colour conversion node-->LDC node-->Mosaic node-->Display node. Now I want to add scaler node between LDC and mosaic node. I'm mentioning the output image format and size of first three modules below.

Camera/capture node: YVYU (YUV422) 1280x724

Colour conversion node: UYVY (YUV 422) 1280x724

LDC: NV12 1280x724

I want to feed the output of newly added scaler to preprocessing block followed by DL model later. The scaler should give the ouput of 512x290 NV12.

Note: Actual required output of scaler is 512x290 i.e down scale by a factor of 2.5 ( (1280x724)/2.5). Next In the preprocessing block, I will have to add top and bottom 15 pixels padding each to make it 512x320).

So can you tell me the changes to make VPAC_MSC to downscale by 2.5?

Thanks,

S Seetharama Raju.

over 2 years ago

0 Brijesh Jadav over 2 years ago

TI__Guru**** 478015 points

Hi Seetharama Raju,

Well, you can instantiate MSC node in between, have input image of size 1280x724 and output image of size 512x290, set the scaling coefficients and that's it. VPAC_Scalar will then work fine. please refer to single camera or multi-camera example. This example uses MSC scalar for downscaling.

Regards,

Brijesh

0 Seetharama Raju over 1 year ago in reply to Brijesh Jadav

Prodigy 170 points

Hi Brijesh,

I have gone through single camera application. There I found the API appIssGetResizeParams(1280, 724, 512, 290, &scaler_out_w, &scaler_out_h) is useful for resizing. Is the above API alone sufficient for the requirement? Please comment on this.

Thanks,

Seetharama Raju.

0 Brijesh Jadav over 1 year ago in reply to Seetharama Raju

TI__Guru**** 478015 points

Hi Seetharama Raju,

No, this Api just calculates the output size. Below API instantiates the scalar node in the application.

obj->scalerNode = tivxVpacMscScaleNode(obj->graph, obj->ldc_out, obj->scaler_out_img, NULL, NULL, NULL, NULL);

Regards,

Brijesh

0 Seetharama Raju over 1 year ago in reply to Brijesh Jadav

Prodigy 170 points

Hi Brijesh,

Can you tell me how to set the scaling coefficients?

Thanks,

S Seetharama Raju.

0 Brijesh Jadav over 1 year ago in reply to Seetharama Raju

TI__Guru**** 478015 points

That's also available in the same file. Please refer to below code.

    if(vx_true_e == obj->scaler_enable)
    {
        tivx_vpac_msc_coefficients_t sc_coeffs;
        vx_reference refs[1];

        printf("Scaler is enabled\n");

        tivx_vpac_msc_coefficients_params_init(&sc_coeffs, VX_INTERPOLATION_BILINEAR);

        obj->sc_coeff_obj = vxCreateUserDataObject(obj->context, "tivx_vpac_msc_coefficients_t", sizeof(tivx_vpac_msc_coefficients_t), NULL);
        if(status == VX_SUCCESS)
        {
            status = vxCopyUserDataObject(obj->sc_coeff_obj, 0, sizeof(tivx_vpac_msc_coefficients_t), &sc_coeffs, VX_WRITE_ONLY, VX_MEMORY_TYPE_HOST);
        }
        refs[0] = (vx_reference)obj->sc_coeff_obj;
        if(status == VX_SUCCESS)
        {
            status = tivxNodeSendCommand(obj->scalerNode, 0u, TIVX_VPAC_MSC_CMD_SET_COEFF, refs, 1u);
        }
    }

Regards,

Brijesh

0 Seetharama Raju over 1 year ago in reply to Brijesh Jadav

Prodigy 170 points

Hi Brijesh,

I have gone through "scale_set_coeff". Still I could not understand how these values have to be changed for obtaining a down scaling of 2.5. Can you please guide on this?

Thanks,

Seetharama Raju.

+1 Brijesh Jadav over 1 year ago in reply to Seetharama Raju

TI__Guru**** 478015 points

But why do you want to change the scaling coefficients? You can use the same coefficient for this scaling operation.

Regards,

Brijesh

0 Seetharama Raju over 1 year ago in reply to Brijesh Jadav

Prodigy 170 points

Hi Brijesh,

Thanks a lot, it worked.

Regrads,

Seetharama Raju.

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TDA4VM: MSC node downscaling for the customized application