On 01/08/2014 08:15 PM, m silverstri wrote:
Thanks.
I am studying android source code.
From here, it has code which open("/dev/video11", O_RDWR, 0) as
decoding device.
http://androidxref.com/4.4.2_r1/xref/hardware/samsung_slsi/exynos5/libhwjpeg/ExynosJpegBase.cpp
What you're looking for might be this proprietary Samsung JPEG codec driver
used in Android.
https://android.googlesource.com/kernel/exynos/+/android-exynos-3.4/drivers/media/video/exynos/jpeg/
If you intend to use mainline kernel you need to consider the s5p-jpeg
driver,
which exposes to user space standard interface without any proprietary
additions
incompatible with the V4L2 spec.
I want to find out which is the corresponding driver code for device
'/dev/video11'.
I suspect these numbers are fixed in the Android kernel (they are hard
coded in the user space library as you're pointing out above), which is
a pretty bad practice.
It's better to use VIDIOC_QUERYCAP ioctl to find a video device with
specific name, as Devin suggested. You can also find a video device
exposed by a specific driver through sysfs, as is done in
exynos_v4l2_open_devname() function in this a bit less hacky code:
https://android.googlesource.com/platform/hardware/samsung_slsi/exynos5/+/jb-mr1-release/libv4l2/exynos_v4l2.c
Thanks,
Sylwester
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