Add 16 kb page support to `decoder_flac` to support Android 15

[maxoertel]

Version

Media3 main branch

More version details

Android 15 adds support for devices with 16 kb page size memory. Any native parts of the app need to be rebuild, otherwise apps will crash at these new devices. Currently, the Flac extension of Exoplayer does not support this. Hence, validating the APK shows UNALIGNED:

TODO:

• Follow steps here to add 16 kb page size support

Devices that reproduce the issue

Any

Devices that do not reproduce the issue

Reproducible in the demo app?

Yes

Reproduction steps

1. Build and run the debug app.
2. Locate the debug APK and unzip it
3. Use the alignment.sh script provided in the official migration guide linked above and run this command:
   sh alignment.sh my_apk_out | grep "arm64-v8a"

(where my_apk_out is the unzipped apk)

Expected result

libflacJNI.so (the Flac lib) should say ALIGNED

Actual result

It says UNALIGNED

Media

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.

[rohitjoins]

Hi @maxoertel,

Thank you for raising this issue. We will add support for 16KB page to all the extension modules and keep you updated.

[rohitjoins]

Hi @maxoertel,

Support for 16 KB page size has been added. Thank you once again for raising this issue.

[maxoertel]

Thx @rohitjoins for adding 16 KB page size support 💪🏼

[Tolriq]

@rohitjoins AFAIK 16k pages requires NDK 27 and all the docs still references NDK 21 as tested solution. Might worth a doc update?

[maxoertel]

@Tolriq I'm very confident that NDK 27 is not required for 16kb pare support. We updated our own libs already and still use NDK 21 and it works fine.

Google even has a dedicated section for below NDK 27: https://developer.android.com/guide/practices/page-sizes#compile-r26-lower

[Tolriq]

Yes but from that part:

In order to test on those lower versions of the NDK on 16 KB devices, canary releases of LTS NDK versions [r21](https://ci.android.com/builds/branches/aosp-ndk-release-r21/grid) (for Windows and Linux only), [r23](https://ci.android.com/builds/branches/aosp-ndk-release-r23/grid), and [r25](https://ci.android.com/builds/branches/aosp-ndk-r25-release/grid) are available on Android CI with 16 KB aligned libc++_shared.so libraries. Regardless, it is recommended to move to Android NDK r27 or higher to update to the 16 KB ELF aligned version of the C++ standard library. Otherwise, your app will fail to install on 16 KB devices today.

Says it requires canary versions of those NDK

[rohitjoins]

Hi @Tolriq,

We recently streamlined the build process for most decoder extensions by switching from ndk-build to CMake. Users no longer need to manually check out the NDK or rely on it directly. Once we upgrade to AGP versions that support NDK version 27, we might need to update the flags for 16 KB page sizes.

Eg: Simplified Flac extension build process