|
Wednesday, April 29. 2009
I’m exactly three months into my Arabic studies in Cairo, where I’ve been taking time off university studies and Amarok development. I’ve realized that acquiring a large vocabulary as fast as you can manage is a crucial part of studying a language intensively, and thanks to the awesome KDE-Edu folks I’ve been successfully barely keeping up with the hundreds of new words I’m assigned per week with Parley.
The major problem I have with Parley is that I have to be in front of my computer to use it!
I know you’re laughing. That’s like saying a major fault of beer is that you have to drink it to get drunk, after all Parley is a computer program.
You’re right, just because I hardly find the time to actually use the computer doesn’t mean I should lay the blame on Parley. Technically, I should blame the denizens of Cairo and their insane traffic. Seriously, too many of my life’s hours are wasted in the smelly, stuffy, taxis of Cairo (today was particularly bad, pardon the rant).
This past weekend I ignored the towering pile of homework and whipped up a little application for Android devices that groks Parley’s kvtml2 file format, displays lessons, and provides flashcard exercises. My app is really an Android Port of the J2ME mobile application MobVoc. Michael, the MobVoc developer, did most of the hard work for me: parsing kvtml2 files into java data structures. Mad props to Michael; I definitely plan to pass along any contribute any bug fixes/optimizations I make to his code (such as sub-lessons support).
The application - unimaginatively dubbed ParleyDroid for now - is extremely bare-bones. Here is the current feature set
- Pick a kvtml2 file from the SD card
- Choose 1 or more lessons to practice
- View flashcards of the words in the selected lessons.
- Gesture support in the flashcards: Long Press marks card as known, Fling Left/Right changes to Next/Prev card.
- Each practice session has a short-term memory: i.e., if you mark a card as known you won’t see it again that session but if you restart the session you will.
- Arabic Support - if the 2nd language is Arabic, it will be rendered correctly on screen
The last feature is probably the most noteworthy. Android, by default does not support RTL or non-Latin scripts, but with a little Android-trickery-that-deserves-another-blog-post I’m finally able to practice my vocabulary in the back of the taxi or while walking along the Nile.
Binary and Source:
ParleyDroid Source
ParleyDroid Android Binary
Obligatory Screenshots (click for full view):
 
 
Sunday, January 25. 2009
Short version: @Ramblurr is my new public Tech/FOSS twitter account, please follow it.
I have been on twitter for quite awhile, for several years at least. My original use case for twitter was something like a web/sms based IRC channel for my good friends from my hometown. Twitter is responsible for keeping us close in the years after we parted ways for different colleges. This use case worked great until my online communities (KDE, tech industry, etc) started jumping aboard the twitter boat.
At first I tried to handle both social spheres?online professional, and raucous college student?with the same account. Needless to say one group did not appreciate the drunken tweets or lengthy star wars quotation contests, and the other group did not appreciate my Java vs C++ discussions. Eventually, I made my account private and left the online technology twitter sphere, but now things are changing.
Twitter has risen to prominence in the online community, and I am missing out on this form of social communication with my fellow technology and open source enthusiasts. So, I’ve renamed my private account, and opened my original for public use.
Please feel free to follow @Ramblurr, my public account, without need to fear a flood of inane, hyper-context-sensitive, ramblings between friends.
Thursday, January 22. 2009
Several of us at Camp KDE?myself included?owe a great debt to Till Adam. When he came to the sunny, beautiful beaches of Jamaica, instead of spending his days lounging on the shore or swimming in the warm Caribbean, he chose to pen himself in a stuffy room with a dozen geeks and teach them Qt.
Till works for Klarälvdalens Datakonsult AB (KDAB), the Qt consultancy firm. Besides working on large-scale, enterprise Qt applications, KDAB provides professional Qt training to such companies as IBM, Boeing, Ericsson, and J.D. Edwards. These training sessions usually run a few thousand Euros per person. With the OK from Nokia and Qt Software, Till provided us with a mini two day training course for free!
While the content and materials Till used during the sessions is copyrighted, the information I learned is not. With his permission I’m going to discuss a few pointers in this post. The topics covered somewhat basic/intermediate Qt skills, so those of you who have been programming with Qt for any length of time might not find anything new or interesting. However, for those, like me, who haven’t quite developed our Qt Fu to the Master level, take away tips from here knowing it was passed from a master.
#1 Most Common Performance Issue in Qt
Converting from a QPixmap to QImage too often.
This tip is actually fairly well known, but apparently KDAB consultants run across this mistake very often while in the field. There is a great discussion of this topic over at KDE’s techbase. In summary:
- A QImage is stored in main memory
- A QPixmap is stored in video memory
- Converting from a QPixmap to a QImage is a very expensive operation (see the above article for the explanation)
#1 Most Common Cause of Crashes in Qt
Deleting this from slots
This tip needs some more explanation. Essentially, a mistake many Qt programmers do is include executable code after emitting a signal. Consider this flow of execution:
- The function Produce::blend() emits signal pineapple()
- The slot slotBlender() deletes the instance of Produce
- The signal/slot connection returns to the function Produce::blend(), which has some other executable code such as variable assignments after the emit.
- Crash. Since the slot deleted Produce, any code following the emit statement that modifies memory is now attempting to write to invalid memory.
One good practice to follow is: don’t have any executable code following the last emit statement in your objects’ methods.
However, the real solution is: Use deleteLater() on your QObjects.
This post is getting somewhat lengthy and I potentially still have two topics to cover (Threading and Model/View). Most likely I’ll dedicate a post regarding threading in Qt (I took better notes during that talk) in the next couple days. Many thanks to Till for the sessions, as well as KDAB and Qt Software for allowing them to happen.
Monday, January 19. 2009
The “conference” ended yesterday as the final presentations were given, however we still have 4 days left here among the sunny beaches. Today Till Adam gave a fantastic lecture-slash-hands-on-workshop of Qt’s Model/View and plugin architecture. Just a couple weeks ago I was slamming my head against the desk trying to wrap my head around Qt’s M/V concepts. Through the creative use of roleplaying (thanks Ade, Jeff, Sebas, and Leo!) and two helpful hands-on exercises I’ve finally gotten a decent grasp of the system. Tomorrow morning we hope to sip QtConcurrent knowledge from the cup that is Till.
I’d write more, but the ocean is calling and I still need to get a Pina Colada.
A few photos from the past couple days, visit flickr to see them all.
Saturday, January 17. 2009
The internet is on the fritz here in Negril, Jamaica at Camp KDE, but while it is working I’ll post this photo taken from the balcony during lunch.
This is also a field test of the Wordpress Android application.
We have had 3 presentations so far. Right now Sebastian Kügler is giving a great talk concerning optimizing your applications for mobile devices.
More quality updates soon.
Wednesday, January 14. 2009
Things have been busy around here! First, there was the end-of-semester rush that occurs right before exams, then there was exams themselves. After the 3-day cross country drive home, I’ve spent the last couple weeks playing Settlers of Cataan with old friends, and hitting the ski slopes a couple times a week.
In between all that I haven’t had much time for development. Actually, I told a small lie. I’ve been pretty busy with a secret project ™, but I can’t post anything about that until the 19th.
Amarok wise, things are looking up. I’ve started to completely refactor the last.fm service in Amarok 2. Expect a more explanatory post (plus screenshots!) soon.
Finally, Camp KDE is a few short days away. During the conference Leo Franchi and I plan to knock out some huge improvmeents to Amarok 2’s Context View.
Gah, Gah, Go, that’s all folks!
 I'm Going to Camp KDE!
Wednesday, November 5. 2008
Earlier this summer I had noticed that National Public Radio (NPR) launched a brand new open API based on open source technologies. My initial reaction was at best skeptical. I assumed any sort of “API” released by a major media outlet would turn out to be nothing more than a few customizable RSS feeds. If the company was particularly progressive the RSS feeds might include full articles, rather than the neutered one-sentence teasers you find in all the big name’s syndicated content.
I couldn’t have been more mistaken. NPR’s API is no small potatoes. Just take a look at the comprehensive Query Generator to get an inkling of the types of complex queries you can create. Looking at the Query Generator also sheds some light on the content you can retrieve using the API. The API’s main page says the API exposes the entire NPR archive of content starting from the launch of the NPR website in 1995. Just how big is this archive? Over 250,000 stories including text, images, video, and audio!
This quote from the article announcing the API caught my eye immediately:
There were quite a few questions that we addressed when developing the API, but one thing that was not really in question was the need to open as much of our content as possible.1
This isn’t the first open media API. BBC was the first to offer a public open access API, however BBC’s API is restricted to the content from the past 7-days. Seven days! That’s nothing compared to the (approx.) 4748 days - and counting - that NPR’s API offers. NPR and the BBC are two large companies leading the technological shift towards open and free information.
But that’s only half the story.
After discovering this fantastic API I had to do something with it, and the new service architecture in Amarok 2 provided the perfect platform to build a NPR mashup. That was several months ago, and at the time the scripting API in Amarok was still being flesh out (Thanks to Peter). On Monday I noticed the BBC scriptable service Nikolaj had created for Amarok 2. I happened to have several hours of free time, so I cooked up a similar service for NPR:
 
You can get it at kde-apps or via the “Get More Scripts” button in Amarok 2’s Script Manager.
There is definitely room for improvement and in fact here are a few things I plan to do with it:
- Display more than 20 stories under a category
- Sort content by date
- Support searching
- Display the full articles, with images, in the context view
Major props and thanks go out to the entire NPR technical team and all the contributors who made API a reality.
Wednesday, November 5. 2008
Earlier this summer I had noticed that National Public Radio (NPR) launched a brand new open API based on open source technologies. My initial reaction was at best skeptical. I assumed any sort of “API” released by a major media outlet would turn out to be nothing more than a few customizable RSS feeds. If the company was particularly progressive the RSS feeds might include full articles, rather than the neutered one-sentence teasers you find in all the big name’s syndicated content.
I couldn’t have been more mistaken. NPR’s API is no small potatoes. Just take a look at the comprehensive Query Generator to get an inkling of the types of complex queries you can create. Looking at the Query Generator also sheds some light on the content you can retrieve using the API. The API’s main page says the API exposes the entire NPR archive of content starting from the launch of the NPR website in 1995. Just how big is this archive? Over 250,000 stories including text, images, video, and audio!
This quote from the article announcing the API caught my eye immediately:
There were quite a few questions that we addressed when developing the API, but one thing that was not really in question was the need to open as much of our content as possible.1
This isn’t the first open media API. BBC was the first to offer a public open access API, however BBC’s API is restricted to the content from the past 7-days. Seven days! That’s nothing compared to the (approx.) 4748 days - and counting - that NPR’s API offers. NPR and the BBC are two large companies leading the technological shift towards open and free information.
But that’s only half the story.
After discovering this fantastic API I had to do something with it, and the new service architecture in Amarok 2 provided the perfect platform to build a NPR mashup. That was several months ago, and at the time the scripting API in Amarok was still being flesh out (Thanks to Peter). On Monday I noticed the BBC scriptable service Nikolaj had created for Amarok 2. I happened to have several hours of free time, so I cooked up a similar service for NPR:
You can get it at kde-apps or via the “Get More Scripts” button in Amarok 2’s Script Manager.
There is definitely room for improvement and in fact here are a few things I plan to do with it:
- Display more than 20 stories under a category
- Sort content by date
- Support searching
- Display the full articles, with images, in the context view
Major props and thanks go out to the entire NPR technical team and all the contributors who made API a reality.
Thursday, September 18. 2008
If there was a blogger award for “Most likely to make timely posts”, then in no possible world would I even be considered for the award. I could list some excuses that sound legit in my head, but the real reason I don’t feel motivated to post often (or on time) is because I’d rather spend that time in Google Reader reading everyone else’s exciting content (that was not sarcastic).
So, lets see… last time I posted I was en route to Akademy 2008 (the KDE developers conference). That was July 30th, now, a month and a half later I am back from Europe (which was amazing), GSoC is over (sad), and class has started (jury’s still out).
Current Status of the MP3tunes Amarok Service
The Good (Works)
- Browsing & Streaming
- Querymaker is as functional as possible with the current API
- Manual Downloading from MP3tunes to Local Collection
- Manual Uploading from any Collection to MP3tunes
The Bad (Doesn’t work)
- AutoSync - 80%- The code is there, however there are problems with the daemon not receiving signals from the MP3tunes’ servers
- MP3tunes playlists support - 0%- Never got started on this
The Ugly
There is one large issue I am still wrestling with. The details of the issue are complicated, but essentially it deals with the way Amarok handles remote tracks in playlists across sessions. Generally, remote tracks’ metadata isn’t cached by Amarok for use between multiple sessions. So, if you add an mp3tunes track to a playlist in Amarok, then restart Amarok and try to play that playlist the mp3tunes track is blank. Now, there exists a method for retrieving that metadata, however it was originally implemented synchronously. When you are retrieving metadata for any significant number of tracks (10+) synchronously, and each one of those retreivals is an HTTP Get request you end up blocking the GUI thread. At Akademy I hacked a way to do this asynchronously, but it is a really nasty hack. I’ve got code on my computer that implements this feature correctly, but it has the nasty habit of crashing Amarok every so often.
Between classes, marching band, homework, and other responsibilities I’m working on getting this ironed out and committed. Hopefully this will happen before the 2.0 release, because right now using MP3tunes in Amarok across sessions is slow and annoying.
Wednesday, July 30. 2008
The ball has been dropped by me - dropped hard - during the past several weeks. First, I was stumped for a week and a half by the glib+qt fiasco, then my development machine’s hard drive shuffled off the mortal coil. Replacing it took a solid week, and when it finally arrived I installed Gentoo. Two days later, the finally install completes as I’m frantically throwing my life’s possessions into a car:
- clothes
- 2 laptops
- 1 Target desk (retail $50)
- assorted books
- 1 blow-up air mattress
Fast forward through seven hours of me hurtling down the interstate at not-so-safe velocities, and here I am, pardoning my recent idleness as my flight to Paris boards at gate D32. Not accomplishing much over the past several weeks suddenly doesn’t seem so bad: I’m going to Europe! There is a week long hack-a-thon at Akademy; I’ll catch up then.
A bientôt!
Thursday, July 17. 2008
I’ve been slacking on the update reports over the past two weeks, because I’m holding out for the exciting post where I say “MP3tunes AutoSync is working! Huzzah!” Sadly, this report isn’t that one.
For the past week I’ve been banging my head against the wall of glib, QtEventLoop, and QThreads. I have quite a headache to say the least, but yesterday thanks to my mentor and Ian, both Amarok developers, my head actually broke through that wall. Literally. GLIB, and Qt are kowtowing at my feet swearing oaths of fealty. They have promised to work together and let me get back to doing fun things, like code new features.
Tuesday, July 8. 2008
Some non-Summer-of-Code related business popped up over the weekend, to take care of which required a slight road-trip. As such, I haven’t had much time to work on my project, however I’m heading back home today and I plan to get the code I have chilling in my local branch pushed to the main subversion repository.
Surprisingly, bulleted lists seem to be the most concise means to list progress [/sarcasm]
- Still working on Harmony integration.
- Harmony authentication is working (Thanks Lateralus from MP3tunes!).
- The daemon is receiving notification updates.
- Notification processing is what I’m working on now.
While looking at my last couple reports about harmony, I realized that the information is somewhat dry. I think this is because harmony is a highly technical, behind the scenes feature, and, also, often it is difficult to inject excitement into mundane programming updates. The humdrum is slightly symbolic of harmony. You will enable it once and forget about it as it silently keeps your music collection synced.
Related posts: GSoC Report Week 5: Harmonizing Amarok, One small step for Amarok?
Wednesday, July 2. 2008
Total Commits: 106 Weekly Commits: 26
I usually aim to post these reports on Monday, but I’m usually wrapping up a final commit or two on Monday night so I wait till Tuesday to post the report. Well now it’s 3:30 on Wednesday morning and I’m just starting. My last commit for “this week” was, oh, about 30 seconds ago.
During the last 7 days I:
- Patched libmp3tunes to support track fetching based off a filekey.
- Used the aforementioned patch in Amarok to enable saving of MP3tunes tracks to playlists.
- Made the MP3tunes Service “Lazy Load” upon Amarok’s start-up.
- Fixed misc non-mp3tunes related Amarok bugs.
- Added libmp3tunes::Harmony to the source tree.
- Created a harmony daemon that runs asynchronously within Amarok.
As usual you can see a list of my most recent commits via my fisheye page.
What the heck is this Harmony nonsense?
Harmony, itself, is a subset of libmp3tunes that provides an api for receiving event notifications from the MP3tunes servers. Essentially, what it boils down to is harmony enables the MP3tunes servers to notify Amarok when a user’s Locker has been changed. This will allow Amarok to assess the changes and perform an appropriate action (e.g., download a new track).
Suppose Jenni buys a song from eClassical and has it loaded directly to her locker. When this happens her Amarok will receive a notification: “Hey Amarok, Jenni just had a track added to her locker.” At which point Amarok will seamlessly download the track to Jenni’s local collection.
Pretty cool right? Sure is, there’s just one caveat: it’s not working yet. Getting harmony to play nice with Amarok was a challenge that took a couple days, but as of this morning harmony is running in Amarok.
By this time next week I plan to have harmony fully integrated with Amarok, so the above scenario can actually take place. Even though the feature freeze that was announced for Amarok 2.0 technically doesn’t include me, I will still be taking some time to polish all the work I’ve done since May.
Tuesday, June 24. 2008
Total Commits: 84 Weekly Commits: 36
Starting these posts with “It was another busy week..” is starting to get boring; I’ll cook up something more exciting for next week.
In case you missed it, in the past seven days history has been made. I’ll let that stand in as the bulk of my weekly report, but a few worthwhile things have occurred since then that deserve a mention.
Remote Track Upload - You can now sideload tracks to your MP3tunes collection from remote sources in Amarok. What the heck is sideload and what remote sources you ask? Sideload is a feature of the MP3tunes API that allows for server-to-server transfers. This means you can give your Locker a URL to a track, and it will automatically be downloaded into your Locker. Currently Amarok sports three services with remote collections that are sideloadable to MP3tunes: Ampache, Magnatune, and Jamendo. This method of transferring is generally very fast, because the transfer bypasses your slow internet connection.
Upload Progress Bar - When you upload (or sideload) tracks to MP3tunes there is now a simple status bar to let you know how far along in the process you are.
Non-Supported Track Filtering - This one is simple: If you try and upload a file-type that MP3tunes doesn’t support, Amarok will tell you and stop that track from being transferred.
- Work on allowing MP3tunes tracks to persist after a restart.
- Flesh out the synchronization system: what it’s going to do, and how it’s going to do it.
- Design any UI widgets needed for the syncing system
The first one will be simple, in fact I plan to code it up after writing this report. These second and third tasks, however, signify that I’m moving into the last stage of the project. According to my original proposal I am ahead by a week, so I’ll be using this week as extra time to plan and get a jump-start on the synchronization framework.
Friday, June 20. 2008
I’m very excited to announce that the first Amarok->Cloud transfer has taken place. Just moments ago, for the first time ever (as far as I’m aware), a track was sent up into the Cloud from a desktop media player, escaping the local collection prison. This track shed the chains of limited accessibility, and is no longer doomed to obscurity, lost in an sql database in my home directory.
This lucky track happened to be Making Me Nervous by Brad Sucks available over at the great indie music label Magnatune.
Early this morning I committed the last bit of code that allows you to upload tracks to your MP3tunes Locker from Amarok. Amarok is the first client, besides the official client, to allow you to do such a thing. One of the great things about this feature is it’s seamless integration in the UI.
Click for the full view
After a short upload I go check the MP3tunes Web Player
From this point I can listen to the track on my phone, on my squeezebox, or any other MP3tunes supported devices.
Of course there are some caveats, but I aim to fix these over the next several days:
- No upload progress information.
- No error handling when you attempt to upload a filetype mp3tunes doesn’t support.
- It’s not possible to upload non-local content (say from magnatune or ampache)
Don’t start thinking that things are winding down; uploading and downloading are only one small part of the show. The end goal is fully automated bi-directional syncing between Amarok and MP3tunes with 100% support for the MP3tunes API.
What exactly does this entail?
- I foresee a “keep in sync with MP3tunes” checkbox for each playlist in the Amarok playlist browser, so you can add/remove tracks from your favorite playlists and thoughtlessly have access to them on any MP3tunes enabled device.
- Imagine clicking “Purchase” at an online music store (like eclassical) and having the tracks instantly available in Amarok and anywhere else you have access to your locker.
- Your friend beams you a track from his Android phone to your Android phone while you are out on the town, and when you get home the track is all ready in your local Amarok collection, added to your smart playlists ready to jam.
- You subscribe to an awesome podcast using Amarok’s built in podcast directory, and seconds after a new episode is released it’s available on your wifi enabled portable player (or phone)
And it all started today.
|
