Build libcamera against Android SDK

[kbingham]

References to get started:

https://proandroiddev.com/how-to-setup-android-sdk-without-android-studio-6d60d0f2812a?gi=6f859505330e

https://github.com/ppetraki/meson-android-helloworld

[rsglobal]

You probably meant NDK: https://developer.android.com/ndk/downloads

As far as I know SDK is for Android apps.

[rsglobal]

Here's the starting point:

1. Download ndk into /opt/ndk directory
2. Clone libcamera
3. Download build.sh and meson_cross_compile.txt into libcamera directory
4. Run ./build.sh
5. $ cd ./build
6. $ ninja

meson_cross_compile.txt
build.zip

[kbingham]

Thanks!, that looks like clear for me to integrate.

[rsglobal]

There're some system dependencies to be installed before building (especially when cross-compiling for ARM). It would be nice to come-up with a dockerfile which will include all required dependencies.

[kbingham]

Is https://github.com/CactiChameleon9/Libcamera-RPiOS-Build-Enviroment useful to you ?

[rsglobal]

I don't have any issues building for Android. But my solution is not upstreamable.
I would like to see initial official Android support to reduce my local delta and then see what can I upstream.

[kbingham]

Which part of your solution is not upstreamable? Nicholas Roth from the other issue is working on the mailing list to determine adding (I expect /your/ makefile wrapper).

The work can only get upstream if someone works on it.

[rsglobal]

Which part of your solution is not upstreamable?

Here's my WIP branch. It's very dirty right now, but it can partially answer the question.
https://github.com/GloDroid/glodroid_forks/commits/libcamera-next

The work can only get upstream if someone works on it.

That won't be me, sorry. I'm already supporting a lot of FOSS repos. And only benefit I have from my FOSS activity is a feeling that world is becoming better. Nobody want to pay for that.

[rsglobal]

@kbingham ,

Can you help me please to understand this line?

adb shell LIBCAMERA_LOG_LEVELS=*:DEBUG lc-compliance
[17:41:46.203161361] [5713]  WARN IPAManager ipa_manager.cpp:114 Public key not valid

Why public key may be invalid?

Here's my generated key:
ipa_pub_key.cpp

UPDATE: libcrypto dep was missing, now it works, signature check is working.

[kbingham]

I've tried following these steps to build with android ndk:

I've created a meson cross file as mesoncross/android-ndk-r25b

[binaries]
ar = '/opt/ndk/android-ndk-r25b/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-ar'
c = '/opt/ndk/android-ndk-r25b/toolchains/llvm/prebuilt/linux-x86_64/bin/x86_64-linux-android33-clang'
cpp = '/opt/ndk/android-ndk-r25b/toolchains/llvm/prebuilt/linux-x86_64/bin/x86_64-linux-android33-clang++'
c_ld = 'lld'
cpp_ld = 'lld'
pkgconfig = '/usr/bin/pkg-config'
strip = '/opt/ndk/android-ndk-r25b/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-strip'

[host_machine]
system = 'linux'
cpu_family = 'x86_64'
cpu = ''
endian = 'little'

and configured with:

meson build/android-ndk-25b/ \
	--cross mesoncross/android-ndk-r25b \
	-Dsysconfdir=/vendor/etc \
	-Dandroid=enabled

...

libcamera 0.0.1

  Versions
    Sources                  : 0.0.1+70-0eb4ccd3

  Paths
    LIBCAMERA_DATA_DIR       : "/usr/local/share/libcamera"
    LIBCAMERA_SYSCONF_DIR    : "/vendor/etc/libcamera"
    IPA_PROXY_DIR            : "/usr/local/libexec/libcamera"
    IPA_CONFIG_DIR           : "/vendor/etc/libcamera/ipa:/usr/local/share/libcamera/ipa"
    IPA_MODULE_DIR           : "/usr/local/lib/libcamera"

  Configuration
    Enabled pipelines        : ipu3
                               raspberrypi
                               rkisp1
                               simple
                               uvcvideo
                               vimc
    Enabled IPA modules      : ipu3
                               raspberrypi
                               rkisp1
                               vimc
    Tracing support          : YES
    Android support          : YES
    GStreamer support        : YES
    Python bindings          : NO
    V4L2 emulation support   : NO
    cam application          : YES
    qcam application         : YES
    lc-compliance application: YES
    Unit tests               : NO

  Subprojects
    libyuv                   : YES

  User defined options
    Cross files              : mesoncross/android-ndk-r25b
    sysconfdir               : /vendor/etc
    android                  : enabled

But I get a lot of host header pollution:

In file included from /opt/ndk/android-ndk-r25b/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/features.h:36:
/usr/include/x86_64-linux-gnu/sys/cdefs.h:64:6: error: function-like macro '__GNUC_PREREQ' is not defined
# if __GNUC_PREREQ (4, 6) && !defined _LIBC
     ^

Do you get this? or have you already resolved such issues ?

[kbingham]

pkgconfig = '/usr/bin/pkg-config'

Seems 'suspicious' to me...

[rsglobal]

Try pkgconfig = ['env', 'PKG_CONFIG_LIBDIR='path_to_NDK_pkgs_dir', '/usr/bin/pkg-config']

[rsglobal]

I haven't tried to build libcamera using NDK yet. I think it would require some minimal sysroot preparation with packages and C headers from AOSP.

[kbingham]

Oh - I thought #54 (comment) was something you had done.
I don't seem to have much in the way of a sysroot for the NDK indeed, so not much for the pkg-config to point to ..