Design and implementation of split/merge operations for efficient multimedia file manipulation

• The conventional file system interface is inefficient for multimedia file editing.
• Two file operation primitives, split and merge, are proposed.
• Complex operations can be built with the combination of the proposed primitives.
• The proposed scheme strikingly reduced the response time for multimedia file editing.
• The proposed scheme is also expected to extend the life span of the flash storage.

Various kinds of smart devices, including personal video recorders, smart TVs, smart phones, and digital cameras frequently manipulate multimedia files, such as frame trimming or inserting. However, because the standard file system APIs do not provide appropriate operations for multimedia file editing, application developers have to implement editing operations by using the conventional read and write operations. Therefore, editing multimedia files unnecessarily incur a large number of I/O operations, resulting in significant performance drawbacks. This paper proposes the design of two novel file system operations, split() and merge(), to remedy the performance overhead of manipulating multimedia files. Unlike conventional file system operations, these operations are carried out only at the metadata level and are accompanied by no actual data movement, so they take negligible time to finish regardless of file size. In addition to the design proposal, this paper introduces the implementation details of the proposed design for three representative file systems: Ext4, FAT32, and exFAT. The evaluation with a commercial digital camera showed that the movie file trimming took less than 1 s for most cases, which is well over 1000% improvement over the conventional approach. In addition, the number of I/O operations, which significantly affects the lifespan of flash memory storage components, was suppressed to less than 1% of that with the conventional approach.