Hello,
I would please like to ask about vivid video output:
I've been trying to understand everything from source code and
documentation, but still not quite sure about its purpose .
Vivid is good example for demonstration of how to write video output driver.
But is it also to be used as a way to test/validate correctness of
application video output (just as done with vivid capture video,
before using the real output HW) ?
On delving in source code, I see in vivid-kthread-out.c file
vivid_thread_vid_out() -> vivid_thread_vid_out_tick() ->
{....
dequeue buffer(vid_out_buf)
....
v4l2_get_timestamp(&vid_out_buf->vb.timestamp);
vid_out_buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
...}
What's the purpose of timestamp modification for the output frames ?
Is it relevant only when using vivid in loopback mode ?
I also encounter old patch of video output loopback (viloop.c), but I
did't find it in released kernel.
Application's video output frames can just be written into file and
played later (as a way to validate the correctness of frames given to
the video output driver), so I wander if there is any other purpose in
vivid video output which I don't see yet.
Best Regards,
Ran
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