I420 pixel format is being used for testing video encoding.
From the driver code, s5p-mfc (exynos 5250) doesn't support I420.
Therefore, it will convert the format to I420 with V4L2 IP.

https://chromium.googlesource.com/chromiumos/third_party/kernel/+/63339c90a50443b7c2473c8a67ae26bccead58e3/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c#35

Recently, I added NV12 input test case, crrev.com/c/1276326.
Then, s5p-mfc fails in the test case [1], even though it supports NV12.

That means, s5p-mfc can encode NV12 input buffers which is converted and output by V4L2IP, but cannot do directly input NV12 input buffer without conversion by V4L2IP.

There can be some causes, some size alignment which is enforced by the IP at its output, but fails if s5p-mfc is used directly.

tfiga@, could you triage this issue? Thanks!

[1] NOTE: it backed green because I disabled the test case on s5p-mfc.
https://stainless.corp.google.com/search?view=matrix&row=board&col=build&first_date=2018-10-20&last_date=2018-10-26&test=video_VideoEncodeAccelerator.h264.bvt&board=daisy&exclude_cts=false&exclude_not_run=false&exclude_non_release=false&exclude_au=true&exclude_acts=true&exclude_retried=true&exclude_non_production=false