[weekly report] Week 10: Rhythmbox iPod/MTP Syncing

[Paul A Bellamy <paul a bellamy gmail com>]

Hi all,
   This last week was a big success for me.  I successfully implemented 
syncing and a properties dialog for MTP devices.  By switching over the 
RBMtpSource to be a sub-class of RBMediaPlayerSource, it inherited all 
the 'sync-ability' of that class, and can now sync easily.  However, 
There is still some code clean-up to do in the RBMtpSource class.  The 
biggest hurdle in implementing the MTP syncing was my flakey MTP 
player.  It would sometimes connect, and sometimes not, and somtimes 
break transferring things.  However, when I compared it back to the Git 
Master version, and got the same errors there I (with a lot of help from 
my mentor), managed to trace the error to my device.  Other than that, 
the biggest challenge was getting the capacity and free space of the 
device (which was not hard, at all).  I also implemented a bit of 
"lazy-loading" style for building the addition/removal lists.  With 
extremely large libraries (say > 70GBs)  building the addition/removal 
list can be processor intensive.  Therefore, we don't want to build the 
same list over and over, when nothing has changed.  This avoids building 
it once when options are selected, and then again when the sync button 
is pressed.

   With syncing working on both iPods and MTP players, I will be 
revisiting Playlist syncing.  Transferring playlists to the device is a 
bit interesting, because there is a many-to-many relationship between 
tracks and playlists.  Furthermore, there is no direct correlation 
between the Rhythmbox query model, and the way iPods handle dynamic 
playlists.  To transfer dynamic playlists would need some sort of 
device-specific converter (which gets dicey on MTP players).  So, for 
now, I will be handling dynamic playlists by converting Rhythmbox's 
dynamic playlists to static ones, when they are transferred.  The part, 
which I am most "worried" about is an efficient way to establish a 
correlation between tracks in the library, and tracks on the device.

   The other minor issue, which I would like to solve, is how to handle 
"Sync All Music" and "Sync All Podcasts" options.  This week, I am also 
hoping to implement these options in the Properties panel(s).  I am 
thinking that these options should be checked by default, so that if 
someone plugs in a device, and hits sync it will automatically begin 
syncing everything.

Paul Bellamy