I have an IMX6Q to which is attached an ADV7180 using 8 bit BT.656. PAL CVBS input works flawlessly using either:
gst-launch tvsrc device="/dev/video1" ! imxv4l2sink
or using /unit_tests/mxc_v4l2_tvin.out
But I cannot get NTSC CVBS to work. The picture rolls as though the IMX6 cannot sync to the incoming video. I've followed the many threads on this forum but have not found a solution that works.
I've tested multiple sources of NTSC video, the 7180 has happily detected the NTSC format, I've tried different values of active_top. I've tried connecting up the hardware HSync and VSync, although they don't appear to be used with the working PAL setup.
- Does NXP/Freescale test with a PAL input or NTSC input when they test their reference boards with mxc_v4l2_tvin.out?
- Is the IMX6 IPU expecting BT.656-3 or BT656-4? A change to the V bit in the SAV/EAV codes happened between these two revisions of the standard, and this would only affect NTSC. (The 7180 can be configured for either.)
- I connected the hardware HSync/VSync signals, but these aren't currently being used (I can disconnect them and PAL still works). Can I force the IMX6 to use these? I tried p->u.bt656.bt_sync_correct = 1; in adv7180.c but it still isn't depending on the hardware sync lines.
- What is the impact of the different CSI clock modes: IPU_CSI_CLK_MODE_CCIR656_INTERLACED, IPU_CSI_CLK_MODE_GATED_CLK etc. Do these dictate use of the hardware H/V sync lines?
I'm running a Yocto build of Kernel 3.14.60.
My device tree pin mux for this device is: