[PATCH v5 00/39] i.MX Media Driver

On Sat, Mar 18, 2017 at 08:41:14PM -0400, Nicolas Dufresne wrote:

Le samedi 18 mars 2017 ? 20:43 +0000, Russell King - ARM Linux a
?crit?:

quoted

On Sat, Mar 18, 2017 at 12:58:27PM -0700, Steve Longerbeam wrote:

quoted

Can you share your gstreamer pipeline? For now, until
VIDIOC_ENUM_FRAMESIZES is implemented, try a pipeline that
does not attempt to specify a frame rate. I use the attached
script for testing, which works for me.

It's nothing more than

? gst-launch-1.0 -v v4l2src ! <any needed conversions> ! xvimagesink

in my case, the conversions are bayer2rgbneon.? However, this only
shows
you the frame rate negotiated on the pads (which is actually good
enough
to show the issue.)

How I stumbled across though this was when I was trying to encode:

?gst-launch-1.0 v4l2src device=/dev/video9 ! bayer2rgbneon ! \
????????videoconvert ! x264enc speed-preset=1 ! avimux ! \
????????filesink location=test.avi

I noticed that vlc would always say it was playing the resulting AVI
at 30fps.

In practice, I have the impression there is a fair reason why framerate
enumeration isn't implemented (considering there is only 1 valid rate).

That's actually completely incorrect.

With the capture device interfacing directly with CSI, it's possible
_today_ to select:

* the CSI sink pad's resolution
* the CSI sink pad's resolution with the width and/or height halved
* the CSI sink pad's frame rate
* the CSI sink pad's frame rate divided by the frame drop factor

To put it another way, these are possible:

# v4l2-ctl -d /dev/video10 --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
        Index       : 0
        Type        : Video Capture
        Pixel Format: 'RGGB'
        Name        : 8-bit Bayer RGRG/GBGB
                Size: Discrete 816x616
                        Interval: Discrete 0.040s (25.000 fps)
                        Interval: Discrete 0.048s (20.833 fps)
                        Interval: Discrete 0.050s (20.000 fps)
                        Interval: Discrete 0.053s (18.750 fps)
                        Interval: Discrete 0.060s (16.667 fps)
                        Interval: Discrete 0.067s (15.000 fps)
                        Interval: Discrete 0.080s (12.500 fps)
                        Interval: Discrete 0.100s (10.000 fps)
                        Interval: Discrete 0.120s (8.333 fps)
                        Interval: Discrete 0.160s (6.250 fps)
                        Interval: Discrete 0.200s (5.000 fps)
                        Interval: Discrete 0.240s (4.167 fps)
                Size: Discrete 408x616
<same intervals>
                Size: Discrete 816x308
<same intervals>
                Size: Discrete 408x308
<same intervals>

These don't become possible as a result of implementing the enums,
they're all already requestable through /dev/video10.

-- 
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