Japan showed healthy gains in digital music sales in the April-June quarter, with PC-based and mobile-based full-track downloads showing especially strong growth, according to data released Aug. 21 by local labels body the Recording Industry Assn. of Japan (RIAJ).

In value terms, digital sales - including mobile- and PC-based downloads - rose 28% to 22.5 billion yen ($204.8 million) in the April-July period. In unit terms, digital sales rose 7% to 119 million units.

While mobile-based master-ringtone sales by the RIAJ's 46 member companies in the quarter were down 17% from the corresponding period of 2007 to 45.5 million units, for a value of 5.1 billion yen ($45.7 million), down 16%, ringback-tune sales rose 11% to 23.9 million units, for a value of 2 billion yen ($18.1 million), marking a 31% rise.

Sales of mobile-based full-track downloads, meanwhile, increased 42% to 36.3 million units, for a value of 11.9 billion yen ($108.7 million), up 52%.

Overall, mobile-based downloads rose 4% to 108.6 million units, for a value of 19.8 billion yen ($180.2 million), up 24%.

PC-based music downloads in Japan in the second quarter were up 52% to 10.3 million units, for a value of 2.2 billion yen ($20.3 million), up 71%.

The RIAJ defines the PC-downloads category as comprising singles, albums, mini-albums and "other related content" sold over wired networks, with albums and mini-albums counting as single units regardless of the number of tracks they contain. The association says that although the data doesn't differentiate between sales of single tracks and albums, singles account for the overwhelming majority of download sales.

The mobile category comprises sales over wireless networks of full single tracks, ring tones, master ring tones and other related content.