Discussion on: How to use Google Colab to package KivyMD applications with buildozer.

[Jaumee]

Hi, I am creating an android app using kivy and buildozer to manage the TelloEDU drone and everything is working fine until im trying to get the image. On my computer, when i ask for get_frame_read().frame (works with opencv VideoCapture) after a couple seconds and some:

[h264 @ 00000272a264c700] non-existing PPS 0 referenced
[h264 @ 00000272a264c700] non-existing PPS 0 referenced
[h264 @ 00000272a264c700] decode_slice_header error
[h264 @ 00000272a264c700] no frame!

The image start flowing.

I think that is the problem then on my android. Just at the moment that I am asking for the image, it crashes with "A/libc: Fatal signal 7 (SIGBUS), code 1 (BUS_ADRALN)".

That is the partcode to upload the frames:

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from tellopy import tello
import cv2
from kivy.clock import Clock

me = tello.Tello()

class WindowManager(ScreenManager):
pass

class ControlWindow(Screen):

def on_enter(self, *args):
    me.connect()
    me.streamon()
    Clock.schedule_interval(self.video, 0.001)

def video(self, dt):
    img = me.get_frame_read().frame
    cv2.imwrite("imagen.jpg", img)
    self.ids.video.source = "imagen.jpg"
    self.ids.video.reload()

kv = Builder.load_file("my.kv")

class MyApp(App):
def build(self):
self.Title = "Control Básico Tello EDU"
return kv

if name == 'main':
MyApp().run()

The kv file is:

WindowManager:
ControlWindow:
:
Image:
id: video
source: "imagen.jpg"

The buildozer .spec file is:

[app]

(str) Title of your application

title = Tello EDU Basic Control

(str) Package name

package.name = TelloEDUBasicControl

(str) Package domain (needed for android/ios packaging)

package.domain = org.test.TelloEDUBasicControl

(str) Source code where the main.py live

source.dir = .

(list) Source files to include (let empty to include all the files)

source.include_exts = py,png,jpg,kv,atlas,txt

(list) List of inclusions using pattern matching

source.include_patterns = assets/,images/.png

(list) Source files to exclude (let empty to not exclude anything)

source.exclude_exts = spec

(list) List of directory to exclude (let empty to not exclude anything)

source.exclude_dirs = tests, bin

(list) List of exclusions using pattern matching

source.exclude_patterns = license,images//.jpg

(str) Application versioning (method 1)

version = 0.1

(str) Application versioning (method 2)

version.regex = version = '"['"]

version.filename = %(source.dir)s/main.py

(list) Application requirements

comma separated e.g. requirements = sqlite3,kivy

requirements = python3,kivy,tellopy,opencv,numpy

(str) Custom source folders for requirements

Sets custom source for any requirements with recipes

requirements.source.kivy = ../../kivy

(list) Garden requirements

garden_requirements =

(str) Presplash of the application

presplash.filename = %(source.dir)s/data/presplash.png

(str) Icon of the application

icon.filename = %(source.dir)s/data/icon.png

(str) Supported orientation (one of landscape, sensorLandscape, portrait or all)

orientation = landscape

(list) List of service to declare

services = NAME:ENTRYPOINT_TO_PY,NAME2:ENTRYPOINT2_TO_PY

OSX Specific

author = © Copyright Info

change the major version of python used by the app

osx.python_version = 3

Kivy version to use

osx.kivy_version = 1.9.1

Android specific

(bool) Indicate if the application should be fullscreen or not

fullscreen = 0

(string) Presplash background color (for new android toolchain)

Supported formats are: #RRGGBB #AARRGGBB or one of the following names:

red, blue, green, black, white, gray, cyan, magenta, yellow, lightgray,

darkgray, grey, lightgrey, darkgrey, aqua, fuchsia, lime, maroon, navy,

olive, purple, silver, teal.

android.presplash_color = #FFFFFF

(list) Permissions

android.permissions = INTERNET, ACCESS_NETWORK_STATE, WRITE_EXTERNAL_STORAGE, READ_EXTERNAL_STORAGE, MANAGE_EXTERNAL_STORAGE

(int) Target Android API, should be as high as possible.

android.api = 31

(int) Minimum API your APK will support.

android.minapi = 21

(int) Android SDK version to use

android.sdk = 30

(str) Android NDK version to use

android.ndk = 23b

(int) Android NDK API to use. This is the minimum API your app will support, it should usually match android.minapi.

android.ndk_api = 21

(bool) Use --private data storage (True) or --dir public storage (False)

android.private_storage = True

(str) Android NDK directory (if empty, it will be automatically downloaded.)

android.ndk_path =

(str) Android SDK directory (if empty, it will be automatically downloaded.)

android.sdk_path =

(str) ANT directory (if empty, it will be automatically downloaded.)

android.ant_path =

(bool) If True, then skip trying to update the Android sdk

This can be useful to avoid excess Internet downloads or save time

when an update is due and you just want to test/build your package

android.skip_update = False

(bool) If True, then automatically accept SDK license

agreements. This is intended for automation only. If set to False,

the default, you will be shown the license when first running

buildozer.

android.accept_sdk_license = False

(str) Android entry point, default is ok for Kivy-based app

android.entrypoint = org.renpy.android.PythonActivity

(str) Android app theme, default is ok for Kivy-based app

android.apptheme = "@android:style/Theme.NoTitleBar"

(list) Pattern to whitelist for the whole project

android.whitelist =

(str) Path to a custom whitelist file

android.whitelist_src =

(str) Path to a custom blacklist file

android.blacklist_src =

(list) List of Java .jar files to add to the libs so that pyjnius can access

their classes. Don't add jars that you do not need, since extra jars can slow

down the build process. Allows wildcards matching, for example:

OUYA-ODK/libs/*.jar

android.add_jars = foo.jar,bar.jar,path/to/more/*.jar

(list) List of Java files to add to the android project (can be java or a

directory containing the files)

android.add_src =

(list) Android AAR archives to add (currently works only with sdl2_gradle

bootstrap)

android.add_aars =

(list) Gradle dependencies to add (currently works only with sdl2_gradle

bootstrap)

android.gradle_dependencies =

(list) add java compile options

this can for example be necessary when importing certain java libraries using the 'android.gradle_dependencies' option

see developer.android.com/studio/write... for further information

android.add_compile_options = "sourceCompatibility = 1.8", "targetCompatibility = 1.8"

(list) Gradle repositories to add {can be necessary for some android.gradle_dependencies}

please enclose in double quotes

e.g. android.gradle_repositories = "maven { url 'kotlin.bintray.com/ktor' }"

android.add_gradle_repositories =

(list) packaging options to add

see google.github.io/android-gradle-ds...

can be necessary to solve conflicts in gradle_dependencies

please enclose in double quotes

e.g. android.add_packaging_options = "exclude 'META-INF/common.kotlin_module'", "exclude 'META-INF/*.kotlin_module'"

android.add_gradle_repositories =

(list) Java classes to add as activities to the manifest.

android.add_activities = com.example.ExampleActivity

(str) OUYA Console category. Should be one of GAME or APP

If you leave this blank, OUYA support will not be enabled

android.ouya.category = GAME

(str) Filename of OUYA Console icon. It must be a 732x412 png image.

android.ouya.icon.filename = %(source.dir)s/data/ouya_icon.png

(str) XML file to include as an intent filters in tag

android.manifest.intent_filters =

(str) launchMode to set for the main activity

android.manifest.launch_mode = standard

(list) Android additional libraries to copy into libs/armeabi

android.add_libs_armeabi = libs/android/*.so

android.add_libs_armeabi_v7a = libs/android-v7/*.so

android.add_libs_arm64_v8a = libs/android-v8/*.so

android.add_libs_x86 = libs/android-x86/*.so

android.add_libs_mips = libs/android-mips/*.so

(bool) Indicate whether the screen should stay on

Don't forget to add the WAKE_LOCK permission if you set this to True

android.wakelock = False

(list) Android application meta-data to set (key=value format)

android.meta_data =

(list) Android library project to add (will be added in the

project.properties automatically.)

android.library_references =

(list) Android shared libraries which will be added to AndroidManifest.xml using tag

android.uses_library =

(str) Android logcat filters to use

android.logcat_filters = *:S python:D

(bool) Copy library instead of making a libpymodules.so

android.copy_libs = 1

(str) The Android arch to build for, choices: armeabi-v7a, arm64-v8a, x86, x86_64

android.arch = armeabi-v7a

(int) overrides automatic versionCode computation (used in build.gradle)

this is not the same as app version and should only be edited if you know what you're doing

android.numeric_version = 1

Python for android (p4a) specific

(str) python-for-android fork to use, defaults to upstream (kivy)

p4a.fork = kivy

(str) python-for-android branch to use, defaults to master

p4a.branch = master

(str) python-for-android git clone directory (if empty, it will be automatically cloned from github)

p4a.source_dir =

(str) The directory in which python-for-android should look for your own build recipes (if any)

p4a.local_recipes =

(str) Filename to the hook for p4a

p4a.hook =

(str) Bootstrap to use for android builds

p4a.bootstrap = sdl2

(int) port number to specify an explicit --port= p4a argument (eg for bootstrap flask)

p4a.port =

iOS specific

(str) Path to a custom kivy-ios folder

ios.kivy_ios_dir = ../kivy-ios

Alternately, specify the URL and branch of a git checkout:

ios.kivy_ios_url = github.com/kivy/kivy-ios
ios.kivy_ios_branch = master

Another platform dependency: ios-deploy

Uncomment to use a custom checkout

ios.ios_deploy_dir = ../ios_deploy

Or specify URL and branch

ios.ios_deploy_url = github.com/phonegap/ios-deploy
ios.ios_deploy_branch = 1.7.0

(str) Name of the certificate to use for signing the debug version

Get a list of available identities: buildozer ios list_identities

ios.codesign.debug = "iPhone Developer: ()"

(str) Name of the certificate to use for signing the release version

ios.codesign.release = %(ios.codesign.debug)s

[buildozer]

(int) Log level (0 = error only, 1 = info, 2 = debug (with command output))

log_level = 2

(int) Display warning if buildozer is run as root (0 = False, 1 = True)

warn_on_root = 1

(str) Path to build artifact storage, absolute or relative to spec file

build_dir = ./.buildozer

(str) Path to build output (i.e. .apk, .ipa) storage

bin_dir = ./bin

-----------------------------------------------------------------------------

List as sections

You can define all the "list" as [section:key].

Each line will be considered as a option to the list.

Let's take [app] / source.exclude_patterns.

Instead of doing:

[app]

source.exclude_patterns = license,data/audio/.wav,data/images/original/

This can be translated into:

[app:source.exclude_patterns]

license

data/audio/*.wav

data/images/original/*

-----------------------------------------------------------------------------

Profiles

You can extend section / key with a profile

For example, you want to deploy a demo version of your application without

HD content. You could first change the title to add "(demo)" in the name

and extend the excluded directories to remove the HD content.

[app@demo]

title = My Application (demo)

[app:source.exclude_patterns@demo]

images/hd/*

Then, invoke the command line with the "demo" profile:

buildozer --profile demo android debug

Do you know where is the problem?

[Ngonidzashe Nzenze]

Hello.

Honestly I have no idea where the problem could be. I haven't worked with tello before but I'm probably guessing it could be something to do with cv2 or how the video is being loaded with get_frame_read. Check out this link which has a demo on using opencv with kivy, it might help.