Imx678 DOL-HDR shift between with long an short exposure frame

Hello everyone,

I have an imx678 and I would like to use the DOL-HDR.
I modified the .dts file but it appears that my short exposure image and my long exposure image are vertically shifted when they are merged together by the Nvidia ISP.

Here is my device tree :

mode1 {/*mode imx678_MODE_3840X2160_DOL_7FPS*/
                                        mclk_khz = "24000";
                                        num_lanes = "4";
                                        tegra_sinterface = "serial_a";
                                        phy_mode = "DPHY";
                                        discontinuous_clk = "no";
                                        dpcm_enable = "false";
                                        cil_settletime = "0";
                                        dynamic_pixel_bit_depth = "10";
                                        csi_pixel_bit_depth = "10";
                                        mode_type = "bayer_wdr_dol";
                                        pixel_phase = "rggb";
                                        active_w = "3872";
                                        active_h = "4480";
                                        readout_orientation = "0";
                                        line_length = "6280";
                                        inherent_gain = "1";
                                        pix_clk_hz = "288000000";
                                        serdes_pix_clk_hz = "480000000";
                                        mclk_multiplier = "4.27";

                                        gain_factor = "10";
                                        min_gain_val = "0"; /* 0dB */
                                        max_gain_val = "300"; /* 30dB */
                                        step_gain_val = "3"; /* 0.3 */
                                        default_gain = "0";
                                        min_hdr_ratio = "16";
                                        max_hdr_ratio = "16";
                                        framerate_factor = "1000000";
                                        min_framerate = "7000000"; /* 4 */
                                        max_framerate = "7000000"; /* 30 */
                                        step_framerate = "1";
                                        default_framerate= "7000000";
                                        exposure_factor = "1000000";
                                        min_exp_time = "15"; /* us */ /* 2line */
                                        max_exp_time = "39000"; /* us */
                                        step_exp_time = "1";
                                        default_exp_time = "30000";/* us */
                                        embedded_metadata_height = "0";

                                        num_of_exposure = "2";
                                        num_of_ignored_lines = "50";
                                        num_of_lines_offset_0 = "30";
                                        num_of_ignored_pixels = "16";
                                        num_of_left_margin_pixels = "8";
                                        num_of_right_margin_pixels = "8";
                                };

I modified “number_of_lines_offset_0” to realign my images because the documentation states that it represent the VBP, and the shift corresponds to the VBP value of the IMX678 datasheet. This did not have any effect, even though I tried multiple values.

Finally, “number_of_lines_offset_0” seems to be parsed, since I also have to change “active_h” when I change it.

hello alexis.kedzia,

you’re working with JP-5 release version, right? may I double confirm the Jetpack release version you’re using?

we’ve experience this issue, and we’ve address the DOL shift failure.
please expect next public release, i.e. JetPack-5.1.2 will include the fixes.

1 Like

Hi Jerry,

Yes I am using the Jetpack 5.0.2.

Thank you for the information, keep me updated please.

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