building hack video

http://www.facebook.com/video/video.php?v=1509130684826&comments

KWAAK

http://code.google.com/p/kwaak3/

Someone says there's lot of cool code inside it. Will post more when I check it out.

C++ function with variable number of arguments like printf

http://bytes.com/topic/c/answers/214807-passing-va_list-sprintf

sprintf and vsprintf and vprintf

JNI calling java code from C++

http://groups.google.com/group/android-ndk/browse_thread/thread/96077556a5434005
http://groups.google.com/group/android-ndk/browse_thread/thread/96077556a5434005/80c242fb2bdc1f05/80c242fb2bdc1f05?pli=1

Method Signature:
http://journals.ecs.soton.ac.uk/java/tutorial/native1.1/implementing/method.html

Other resources:
http://download.oracle.com/javase/6/docs/technotes/guides/jni/spec/functions.html#wp16660
http://www.public.iastate.edu/~java/docs/guide/nativemethod/functions.doc.html#16656
 

JNI free local or gloal references to avoid overflow

http://java.sun.com/docs/books/jni/html/refs.html#27567

because

http://stackoverflow.com/questions/4174453/android-native-process-provoke-referencetable-overflow-after-a-while-android-n

Fix android activity screen orientation

In your activity class insert code:
    @Override
    public void onConfigurationChanged(Configuration newConfig)
    { super.onConfigurationChanged(newConfig);
    }

In your manifest activity tag, declare attribute:
 android:screenOrientation="portrait"

How to implement the source's relative path or absolute unix format path in subdir.mk automatically

How to implement the source's relative path or absolute unix format path in subdir.mk automatically :

eclipse subdir.mk target pattern contains no `%'.  Stop.:

http://www.eclipse.org/forums/index.php?t=tree&th=164513&

Android NDK stack trace analyser

http://code.google.com/p/android-ndk-stacktrace-analyzer/wiki/Usage

Predator sound in android

Configure AudioRecord input as stereo and AudioTrack output as mono. You will get sound as if a predator's listening.

'Must Override a Superclass Method' Errors after importing a project into Eclipse

http://stackoverflow.com/questions/1678122/must-override-a-superclass-method-errors-after-importing-a-project-into-eclipse

Problems solved while Making CPP app work on eclipse CDT with cygwin

On Windows.
Using libsndfile to decode wav file to raw pcm.

Problem1: Linking to the external library  libsndfile.
Extracting/installing libsndfile gave me the header and DLL.

In Eclipse, Set [Project->Properties->C/C++ General->"Paths and Symbols"->include] and  [Libraries] to the .h and .dll files respectively.(F:\libsnd\includes\libsndfile-1.h and F:\libsnd\libsndfile-1.dll)
Result: While linking "File not found: libsndfile-1.h"

Solution:
Added folder containing libsndfile-1.dll (F:\libsnd\) to [Project->Properties->C/C++ General->"Paths and Symbols"->Library Paths] and added "sndfile-1" to [Libraries] {"libsndfile-1.dll" - ["lib", ".dll"]}

Solved.

Problem2: Now EXE is generated but on "Run" throws "multiple target patterns. Stop." in some ".d" file

http://dev.eclipse.org/newslists/news.eclipse.tools.cdt/msg12202.html : The ":" in path to header file is detected as a new target.

Solution: 

Changed "F:\libsnd\includes\libsndfile-1.h" to "/cygdrive/f/libsnd/includes/libsndfile-1.h" in [Project->Properties->C/C++ General->"Paths and Symbols"->include]

Solved.

Problem3: While debugging it says "gdb unknown target exception"

Solution: http://wiki.eclipse.org/CDT/User/FAQ#I_get_the_message_.22gdb:_unknown_target_exception_0xc0000135_at_0x7c9766c6.22

Add path to DLL file in environment variable "PATH". Restart eclipse.

Or Copy the dll to the project folder

Tried editing the path variable.

Solved.

Android settings app - add item to it

http://stackoverflow.com/questions/3524110/how-to-add-preference-of-custom-input-method-to-android-settings-app

Android UI- layout views for multiple screen sizes

http://stackoverflow.com/questions/2000892/whats-the-relationship-between-pixels-and-scaled-pixels

http://developer.android.com/guide/practices/screens_support.html

Android service start on boot

http://www.androidsoftwaredeveloper.com/2009/03/20/how-to-start-on-boot/

Android services

http://mindtherobot.com/blog/37/android-architecture-tutorial-developing-an-app-with-a-background-service-using-ipc/
http://www.helloandroid.com/tutorials/musicdroid-audio-player-part-ii
http://marakana.com/forums/android/examples/60.html
http://www.androidcompetencycenter.com/2009/01/basics-of-android-part-iii-android-services/


http://blog.pocketjourney.com/2008/04/04/tutorial-custom-media-streaming-for-androids-mediaplayer/

Android multithreading

http://developerlife.com/tutorials/?p=290 -How to build a service-enabled Android app – Part 3/3 Multithreading
http://android-developers.blogspot.com/2010/07/multithreading-for-performance.html -Multithreading For Performance
http://developer.android.com/resources/articles/painless-threading.html - thats it

Reactable -digital audio processing

http://www.youtube.com/watch?v=Mgy1S8qymx0&feature=related -reactable live performance @ submixpro studio torino 02
http://www.youtube.com/watch?v=PGiasLiGTX4&feature=related

CLAM- digital audio processing

http://clam-project.org/ -The FAQs are a good place to start.

http://www.mtg.upf.edu/

http://parumi.org/

http://www.ohloh.net/p/clam

 

Digital Audio Processing notes - from basics to who knows

http://en.wikipedia.org/wiki/Amplifier - basically wanted to check why gain can't be increased to infinity without affecting the information in audio(quality).
The gain of an amplifier is the ratio of output to input power or amplitude, and is usually measured in decibels.
The bandwidth of an amplifier is the range of frequencies for which the amplifier gives "satisfactory performance". The definition of "satisfactory performance" may be different for different applications. However, a common and well-accepted metric is the half power points (i.e. frequency where the power goes down by half its peak value) on the output vs. frequency curve.
In ultra high fidelity amplifier design, the amp's frequency response should extend considerably beyond this (one or more octaves either side) and might have −3 dB points < 10 and > 65 kHz.
Professional touring amplifiers often have input and/or output filtering to sharply limit frequency response beyond 20 Hz-20 kHz; too much of the amplifier's potential output power would otherwise be wasted on infrasonic and ultrasonic frequencies, and the danger of AM radio interference would increase. 
Modern switching amplifiers need steep low pass filtering at the output to get rid of high frequency switching noise and harmonics.
Efficiency is a measure of how much of the power source is usefully applied to the amplifier's output.
Commercially available Class D switching amplifiers have reported efficiencies as high as 90%.
An ideal amplifier would be a totally linear device, but real amplifiers are only linear within limits.
When the signal drive to the amplifier is increased, the output also increases until a point is reached where some part of the amplifier becomes saturated and cannot produce any more output; this is called clipping, and results in distortion.
Noise is an undesirable but inevitable product of the electronic devices and components


http://en.wikipedia.org/wiki/Switching_amplifier - A Class D amplifier or switching amplifier is an electronic amplifier where all power devices (usually MOSFETs) are operated as binary switches. They are either fully on or fully off. Ideally, zero time is spent transitioning between those two states.


http://www.audiosonica.com/en/course/post/2/Index- cool. got it from wikiversity. study sound effects concepts from here.
http://en.wikiversity.org/wiki/Getting_started_with_sound_recording
http://en.wikiaudio.org/Main_Page - on it.
http://en.wikibooks.org/wiki/Reaktor/Links/DSP
http://www.musicdsp.org/showmany.php -source codes :))) couldn't be better
http://www.digitalfilter.com/enindex.html
search "digital audio processing" on wikibooks
http://www.halfbakery.com/idea/Noise_20Cancelling_20Voice_20Amplifier -One would not want these voice wavelengths amplified, for fear of deafening the user by amplifiying noise components (eg: cymbals) which happened to be in that wavelength as well. The NCVA improves the signal of voice sounds by adding a low background of white noise at these same voice frequencies. This will not make voices louder, but will make them sharper. That's stochastic resonance.

http://www.freepatentsonline.com/4506379.html
http://www.freepatentsonline.com/4506379.pdf

http://members.misty.com/don/hivoice.html -interesting.How to Get More Apparent Voice Audio Power with Less Amplifier Power! Some about some "formants"
http://www.cs.cmu.edu/~music/icm/slides/week_10.pdf -Introduction to Computer Music. Week 10 - The Human Voice. More "formants"
http://users.otenet.gr/~athsam/speetch_filter.htm -for electronicians

IMPORTANT:Avoid BaseAdapter.getview() for all unchanged data items. HowTo: ListView, Adapter, getView and different list items’ layouts in one ListView

http://android.amberfog.com/?p=296

Couchdb resources

http://wiki.apache.org/couchdb/Introduction_to_CouchDB_views
http://wiki.apache.org/couchdb/HTTP_view_API
http://guide.couchdb.org/draft
http://wiki.apache.org/couchdb/EntityRelationship
http://wiki.apache.org/couchdb/HTTP_Document_API

Audacity: setup source- visual studio

First things first- install wxWidgets
http://wiki.wxwidgets.org/Downloading_and_installing_wxWidgets- its just about the env var "WXWIN"
http://wiki.wxwidgets.org/Microsoft_Visual_C%2B%2B_Guide

Audacity: Noise removal

http://wiki.audacityteam.org/wiki/HowAudacityWorks#Noise_Removal - check out the section on tinkling effects

JAVA performance measurement- An effective and the most complicated tool ever :P

ANSWER:- A Stopwatch that hardly ticks.
http://java.sun.com/docs/books/performance/1st_edition/html/JPMeasurement.fm.html

Works great though.

JAVA JNI monitors

http://java.sun.com/docs/books/jni/html/other.html

advanced stuff- android in industrial automation

http://android.serverbox.ch/

Android audio

http://tunepal.wordpress.com/2010/06/19/i-did-something-very-clever-today/  - FFT native Vz Java

http://www.androidzoom.com/android_applications/multimedia/jasuto-modular-synthesizer_gxvh.html?p=10

http://android.serverbox.ch/ - Cool

Android Embedded activity

http://www.mail-archive.com/android-beginners@googlegroups.com/msg15982.html

http://markmail.org/message/b3zfvuw7klgnz7f2 - condition for permission to embed

http://code.google.com/p/android/issues/detail?id=8818 - mem leak in localactivity manager. Status to be verified.

Audio concepts tutorial- Onset detection

http://apistudios.com/hosted/marzec/badlogic/wordpress/?cat=18

Kill android app

http://stackoverflow.com/questions/2550099/how-to-kill-an-android-activity-when-leaving-it-so-that-it-cannot-be-accessed-fro

http://www.androidcompetencycenter.com/2009/01/android-basics-managing-activity-states-part-i/

http://androidforums.com/application-development/133372-onpause-onstop-problems.html

Garbage collection and performance

http://www.ibm.com/developerworks/java/library/j-jtp01274.html - Hints, tips, and myths about writing garbage collection-friendly classes

GOLD! card - How to create and flash/debrand

http://androidforums.com/htc-desire/67098-how-flash-debrand-your-desire.html
http://theunlockr.com/2010/03/10/how-to-create-a-goldcard/

Custom Adapter with a Listview

http://developerlife.com/tutorials/?p=327

API demos notes

1. SharedPreferences : http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/PersistentState.html
http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/RedirectEnter.html - follow the classes in the source for advanced SharedPreferences ops.
eg: preferences.edit().remove("text").commit();

2. TextView.BufferType.EDITABLE - This allows us to later extend the text buffer : http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/ReceiveResult.html

3. Example of removing yourself from the history stack after forwarding to another activity(just call finish) : http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/Forwarding.html

4. Translucent activity - android:theme="@style/Theme.Transparent" in the activity declaration in manifest : http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/TranslucentActivity.html

5. Translucent+BLUR background -

    // Have the system blur any windows behind this one.
       getWindow().setFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND,
       WindowManager.LayoutParams.FLAG_BLUR_BEHIND);
Also in manifest - android:theme="@style/Theme.Transparent"> :  http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/app/TranslucentBlurActivity.html

6. Services : later

7.

Layout inflation. Create view from XML

http://developerlife.com/tutorials/?p=303 - Just use LayoutInflator instead of ViewInflate. See http://osdir.com/ml/Android-Developers/2010-02/msg03977.html where it says VI was replaced with LI.

save images to file, load images from file

http://www.brighthub.com/mobile/google-android/articles/64048.aspx

Adding tabs dynamically

http://www.androidguys.com/2008/08/12/adding-tabs-dynamically/

My Android links

http://developerlife.com/tutorials/?p=300 - Getting started

http://android-developers.blogspot.com/2009/02/android-layout-tricks-1.html - Using relativelayout to reduce embedding of linearlayouts.

http://mobiforge.com/designing/story/understanding-user-interface-android-part-3-more-views - viewswitcher

http://groups.google.com/group/android-developers/browse_thread/thread/9b7dfa2cd9abec6b - android audio discussions April2010

http://groups.google.com/group/android-developers/browse_thread/thread/dda83b16eda1f848/b5d3cc89efea6dbd?lnk=gst&q=audio+direct+buffer#b5d3cc89efea6dbd - why not use NDK private APIs.

http://www.androidcompetencycenter.com/2009/01/android-basics-managing-activity-states-part-i/

http://android-developers.blogspot.com/2010/07/multithreading-for-performance.html

http://source.android.com/porting/dalvik.html - android dalvik official page

Android error: "audiorecord Could not get audio input for record source 1"

http://comments.gmane.org/gmane.comp.handhelds.android.devel/84064 - says: "I was trying to start recording
from 2 separate threads at the same time causing a conflict."

http://langtagsandroid.langtags.com/blog/?p=605 -  says: Everytime you get an error instantiating AudioRecord it doesn´t release it´s resources the way it should so you won´t be able to request it again unless you restart your phone (or close and reopen
the emulator).

This solution (restarting emulator) worked for me

Android AudioTrack-AudioRecord native API usage and recommendations

http://markmail.org/message/ikt3yvfag6pfr342#query:android%20audiotrack%20native%20api+page:1+mid:ikt3yvfag6pfr342+state:results

Android: Horizontal Progress Bar

<ProgressBar
android:id="@+id/ProgressBar01"
android:layout_height="wrap_content"
android:layout_width="250px"
style="?android:attr/progressBarStyleHorizontal">
</ProgressBar>

Android NDK exceptions

http://groups.google.com/group/android-ndk/browse_thread/thread/89db67ed1fbf6450/6f156e8cd5b27193

Android NDK step-by-step

http://mindtherobot.com/blog/452/android-beginners-ndk-setup-step-by-step/

http://www.aton.com/porting-applications-using-the-android-ndk/

Android Layout tutorials

http://developer.android.com/resources/tutorials/views/index.html

Linear
Relative
Table
Grid
Tab
List

Android SlidingDrawer

http://www.androidpeople.com/android-sliding-drawer-example-tutorial/

http://developer.android.com/reference/android/widget/SlidingDrawer.html

Android viewflipper and animated menu

http://www.warriorpoint.com/blog/2009/05/26/android-switching-screens-in-an-activity-with-animations-using-viewflipper/
http://www.agilemedicine.com/medBlog/?p=32
http://www.codeshogun.com/blog/2009/04/16/how-to-implement-swipe-action-in-android/
http://whyandroid.com/android/174-flipping-your-views.html
http://android-journey.blogspot.com/2009/12/android-viewflipper-and-slidingdrawer.html

Low Level Android app fundamentals: Rookie/Novice/fresher...

APPLICATION COMPONENTS:

1. Activity(ACT)

activity, window(W), view(V)
Activity.setContentView()

2. Service(SVC)-

3.  Broadcast Receiver(BR)- 

4. Content Provider(CP)- 

ContentProvider(CP) and ContentResolver(CR)

ACTIVATING COMPONENTS USING INTENT

ACT:

Context.startActivity() 

Activity.startActivityForResult(). 

getIntent() 

onNewIntent() 

onActivityResult()

SVC:

Context.startService()

onStart() 

Context.bindService() 

onBind() 




BR:

Context.sendBroadcast()

Context.sendOrderedBroadcast()

Context.sendStickyBroadcast()

onReceive()





SHUTTING DOWN COMPONENTS

ACT:
finish()
finishActivity(). (startActivityForResult())


SVC:
stopSelf() 
Context.stopService().



THE MANIFEST FILE

<activity> 

<service>

<receiver>

<provider>

Context.registerReceiver().

INTENT FILTERS

ACTIVITIES AND TASKS

The principal Intent flags are:

FLAG_ACTIVITY_NEW_TASK
FLAG_ACTIVITY_CLEAR_TOP
FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
FLAG_ACTIVITY_SINGLE_TOP

The principal <activity> attributes are:

taskAffinity
launchMode
allowTaskReparenting
clearTaskOnLaunch
alwaysRetainTaskState
finishOnTaskLaunch 

High Level Android app fundamentals: Rookie/Novice/fresher...

http://developer.android.com/guide/topics/fundamentals.html - nothing better

Clean URLs with Drupal-UrlRewriteFilter-Quercus-Jboss

http://www.brianshowalter.com/blog/running_drupal_on_quercus - There's a nice RewriteRule-RewriteMatch combo classes for UrlRewriteFilter posted at this blog.
But it's designed  for tomcat and didn't work on following JBoss configuration right away.
The JBoss config:
1. JBoss-4.2.2
2. Deploying the Quercus web-app(with Drupal inside) as exploded war (Folder name= "myapp.war").
3. Quercus 403
4. Drupal-6.17.
5. UrlRewriteFilter-320
Steps that worked for me:
1. Follow  the above blog at brianshowalter.com.
2. Download UrlRewriteFilter source code from http://code.google.com/p/urlrewritefilter/
(http://code.google.com/p/urlrewritefilter/downloads/detail?name=urlrewritefilter-3.2.0-src.zip&can=2&q=)
3. You must have already downloaded drupalrewrite_0.1 in step1.
4. Couldn't find a link for posting comments on above blog. Hence posting the modified source code here. Kindly setup UrlRewriteFilter and drupalrewrite_0.1 sources with all required libs in eclipse etc. and copy the compiled classes to your myapp.war/WEB-INF/classes.
5. Checkout updated sources for drupalrewrite from http://drupalrewritefilter.googlecode.com (http://code.google.com/p/drupalrewritefilter/source/checkout) and compile/jar and copy to WEB-INF/lib(jar) or WEB-INF/classes(class) as you wish.
6. Good to go.

Thank you.

Removing HTML tags from a String using Regex

result = data.replaceAll("\\\\n","<br/>"). //replace \n with <br/>, 

replaceAll("\\\\", ""). //remove stray "\"s

replaceAll("\\\"", "\\\\\""). // and escape double quotes

replaceAll("<[\\p{Alnum}\\p{Space}\\.\\-=/:\\\"\\\\;]*>"," "). //remove all opening html tags

replaceAll("</[\\p{Alnum}]*>"," "); //remove all closing html tags

High Level Hadoop MapReduce: Rookie/Novice/fresher...

MapReduce borrows a lot from functional programming(Lisp/ML/Scheme). Func. prog. expects to process lists of data frequently, hence they have a lot of inbuilt iterator-mechanisms and higher-level functions called list-comprehensions that are operators over lists. Two of these operators are map and reduce. Like map operator, Mapper takes a record (assumed to be a key-value pair) but can emit multiple key-value pairs(map operator does only one). A characteristic of MapRed paradigm is that mapper should be processing individual records in isolation of one-another.(One Record = up to you- depends on the class that loads the data from the block into mapper as k-v pair records).
Reducer takes a key and list of values and can emit none, one or multiple key-value pairs.

It's a general notion to ignore the key that's input to a map task. They could be byte offset to a chunk of data.

People also skip mapper or more often reducer, if it suffices for the app.
Reducers don't start until all mappers complete. They run on the same nodes as mappers(after mappers complete).
All values with same keys are collected from all mappers(that emitted that key) and sent to same reducer. This involves network communication. If multiples keys are processed by one reducer, they are presented to it in sorted order(No assumptions about the values of those keys). This is called "sort and shuffle" phase handled by the underlying framework. A single reduce task processes single key(it takes one key and list of values as input).

Within sort and shuffle, there can be a user-defined combine task that's run on the mapper's intermediate results. If app-logic allows it could be same as reducer code(eg: if reducer is commutative and associative). Combining phase is disabled by default. It runs on the mapper machine. It's solely for reducing network data-load and load on reducer. Don't perform any data-specific operation in combine phase. It may run zero, one or more times.(depends on size of data). Example is the word-count map reduce jobs. Mapper emits [, 1] . Combiner aggragates that mapper's results to [, n](no. of times the word occurred in the input blocks local to that machine). Then comes the reducers(mappers die).

Thank You.

Hibernate JDBCConnectionException: could not execute query- Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:

"org.quartz.JobExecutionException: could not execute query; nested exception is org.hibernate.exception.JDBCConnectionException: could not execute query [See nested exception: org.springframework.dao.DataAccessResourceFailureException: could not execute query; nested exception is org.hibernate.exception.JDBCConnectionException: could not execute query]
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 13,768,115 milliseconds ago.  The last packet sent successfully to the server was 13,768,115 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem."

This problem occurred in a Grails application having a cron job that requests some data from an external server, processes it and persists some results. However the data is very large and the app requires 2+ Hrs. to process all of it before persisting a small result. The jdbc connection remains idle during this time.
Setting 'autoReconnect=true' or max_idle_time is certainly not a reliable solution for this.

What worked for me:
http://sacharya.com/grails-dbcp-stale-connections/: This was my exact problem. It says "By default, DBCP holds the pooled connections open for infinite time. But a database connection is essentially a socket connection, and it doesn’t come for free. The host OS, database host, and firewall have to allocate a certain amount of memory and other resources for each socket connection. It makes sense to those devices not to hold onto idle connections for ever. So the idea is to make sure that you don’t have stale connections in your pool that would otherwise be silently dropped by OS or firewall."

Modified my Datasource.groovy for working out this solution.
Had to use the following syntax from: http://stackoverflow.com/questions/376544/grails-mysql-maxpoolsize
Modified my Datasource.groovy:

dataSource {
    pooled = true
    dbCreate = "update"
    url = "jdbc:mysql://localhost/yourDB"
    driverClassName = "com.mysql.jdbc.Driver"
    username = "yourUser"
    password = "yourPassword"
    properties {
        maxActive = 50
        maxIdle = 25
        minIdle = 5
        initialSize = 5
        minEvictableIdleTimeMillis = 60000
        timeBetweenEvictionRunsMillis = 60000
        maxWait = 10000     
    }   }

Other relevant links:

http://drglennn.blogspot.com/2009/05/javasqlsqlexception-communication-link.html
http://commons.apache.org/dbcp/configuration.html
http://www.grails.org/DataSources+New
http://www.grails.org/1.2+Release+Notes