GSoC Proposal: Statistics synchronization for pluggable devices and Last.fm

Tue Mar 20 23:06:16 UTC 2012

Hi Teo, Bart and list,
as suggested by Teo, I've decided to try to take part in GSoC 2012 working as 
a student on Amarok. My idea is not on the KDE Ideas page, but I've been 
playing with (a variant of it) for months.

Continues a very draft of my GSoC proposal. I'd be very grateful for any 
possible comments, pointed-out omissions or questions that may arise.

Introduction
=======
Amarok has an ability to store per-track play statistics such as play count, 
first & last played date, rating and labels. It then has powerful means to 
generate custom-tailored playlists based on gathered statistics (e.g.: play me 
what I've listened to last month) that many users like to exploit. This works 
well when your computer is the only device you play music from. More likely 
situation is that you play music using Amarok at home, listen to iPod while 
commuting and use Amarok or another music player at work. All these 3 devices 
are able to keep track of what you've listened to, but each one only a third 
of it, which makes Amarok statistics more or less useless. This project aims 
to remedy the situation; Last.fm is an online service that can keep track of 
music a user listens to[1] and can help us with a part of this project. Amarok 
Users group on Last.fm has over 23 000 users.[2]

Project Goals
========
This project will implement:
 * track statistics synchronization between Amarok collections that support 
statistics; these are currently Local Collection and iPod Collection, but the 
framework will be general
 * Last.fm scrobbling from pluggable media players that support statistics 
(iPods, currently) using the general framework from previous point
 * ability to synchronize labels from Amarok to Last.fm
 * ability to synchronize play counts, first & last played date from Last.fm to 
Amarok collections (other way around is already implemented by scrobbling)
 * GUI dialogue for performing the synchronization/resolving conflicts

Bonus points (what will Amarok gain for free):
 * ability to synchronize statistics of Amarok and other media player that 
scrobbles to Last.fm
 * track statistics backup through Last.fm

Caveats:
 * Last.fm has no concept of track ratings. This can be however worked around 
by special Last.fm-side labels such as "7/10 stars"
 * advanced features will be only available for Last.fm users; Last.fm is free 
to use, but the data are public which may be unpleasant for certain users

Implementation
=========
Amarok represents audio tracks by Meta::Track abstract C++ class that provides 
getter methods for meta-data (title, artist, album..) and getter/setter 
methods for statistics (rating, play count...). These tracks are grouped into 
so-called Collections, where each Collection represents one source of songs 
(iPod, Local, USB Mass Storage..). Tracks from different collections will be 
matched together using their meta-data and other collection's QueryMaker to 
perform the search. Moreover, iPods provide additional data that can be 
used for conflict-resolution: app_rating and recent_playcount. [3] I plan to 
expose these as new capability offered by Collections. This capability will 
also be used to implement Last.fm scrobbling from iPods (in fact, every 
collection that will support this capability), exploiting recent_playcount 
field in the iPod case. It should be noted that I have already implemented 
similar synchronization in my spare time back in summer 2011 [4], but I was 
not satisfied with its iPod-specific design and GUI, so I decided not to strive 
for its inclusion. But I have the code working and ported to Amarok 2.5, so it 
can be used to fast-start this project.

Another interesting note is that scrobble-from-iPod-to-Last.fm was functional 
in Amarok 1.4 days, but this feature got dropped during rewrites leading to 
2.0, so this will fix one long-overdue regression.

Speaking about Last.fm integration, Last.fm provides rather nice RESTful API 
[5] a subset of which is already used through liblastfm [6] library in Amarok 
to submit (scrobble) currently played songs. I plan to reuse this library and 
Amarok code dealing with it; the Last.fm API is powerful enough to support all 
claimed features. There is already even Last.fm on-line service Collection, 
but it focuses on playing Last.fm radio streams and doesn't handle individual 
tracks. In order to implement actual synchronization with Last.fm, user's 
Last.fm Library (that contains relevant track data) can be represented as a 
new (invisible) Collection or as special case in synchronizer, I have yet to 
decide this design choice.

Timeline
=====
[To be done when the general idea is accepted.] Generally: inter-collection 
synchronization will be first and will be done by the midterm evaluation, 
Last.fm support will be second. I'm already quite bound to Amarok community, 
so I can finish the design, iron-out some details and perhaps present some GUI 
mockups during the community bonding period.

If accepted, GSoC will be my main commitment during the summer, I plan to have 
a week-long vacation and a few 3-day trips, but I'm used to work during 
weekends on open source projects, so the vacation will be compensated.

About me
======
I'm a 24-year-old student of mathematical informatics from Prague, Czech 
Republic. I've been passionate about FLOSS since high school and recently I've 
started contributing to a couple of projects (manly KDE related), most notably 
Amarok where I worked on fixing various bugs singe last autumn [7] and recently 
I've rewritten the iPod collection from scratch [8] as suggested by Amarok's 
Bart Cerneels; I plan to submit a review request for this in coming weeks. 
I've been also particularly active on KDE's bugzilla where I've commented to 
more than 300 bugs.[9] I know C, C++, Python, Java, a bit of French (pun 
intended) and some other less relevant languages. Thanks to my work on Amarok 
I have some experience in GUI programming in Qt & KDE libs.

I've chosen Amarok because I fell in love with it last year, and statistics 
synchronization because it is an area where I found it a bit lacking; I'm a 
music enthusiast who dislikes to listen to the same song twice in a week and I 
believe more Amarok users are that picky and will therefore benefit from this 
work.

I can be reached via e-mail matej at laitl.cz which serves as my Jabber and 
Google account, too. I sometimes hang on #amarok under nick strohel.

[1] http://www.last.fm/user/strohel
[2] http://www.last.fm/group/Amarok+Users
[3] http://www.gtkpod.org/libgpod/docs/libgpod-Tracks.html#Itdb-Track
[4] http://mail.kde.org/pipermail/amarok/2011-June/032736.html
[5] http://www.last.fm/api/intro
[6] https://github.com/mxcl/liblastfm/
[7] https://www.ohloh.net/accounts/strohel
[8] http://goo.gl/B3Odu
[9] http://goo.gl/afJN3