Stream Manager—Targeting High-functionality AV Equipment at Low Cost
Mika Mizutani, Damien Le Moal, 浩明 鷲見, Masanori Hashio · 2007
INTRODUCTION AS a result of the digitization of contents such as music and images, AV (audio-visual) equipment fitted with storage, namely, flash memory and HDDs (hard disk drives), is becoming more popular. Moreover, thanks to improved quality and resolution of music and images, the volume of contents is tending to grow ever bigger, and HDDs are becoming indispensable for AV equipment, particularly devices handling image contents. Under these circumstances, focusing on capability of AV equipment and features of image contents, Hitachi is making efforts to provide middleware applications for HDDs (see Fig. 1). As regards AV equipment handling image contents, simultaneous recording of multiple programs and simultaneous handling of high-definition images (such as normal playback and “trick play” during program recording) are necessary. In addition, high-definition images have a high bit rate that is three times that of normal images on conventional DVDs (digital versatile disks), and it is difficult to secure the rate for each access during simultaneous access to an HDD. As for these challenges, by means of processing OVERVIEW: With the popularization of AV equipment incorporating HDDs, DVD/HDD recorders, plasma TVs with built-in HDDs, broadband PCs, etc., “time shift viewing”—where recorded pictures are viewed off the hard disk—is becoming commonplace. In contrast to recording media like videotape, an HDD allows read and write operations to be executed simultaneously. Accordingly, recorded programs can be watched while being recorded, and multiple programs can be recorded simultaneously. From now onwards, applications for enjoying recorded programs over networks will also become more popular. Hitachi has developed and is commercializing two middleware solutions that provide applications with hard-disk utilization adapted to the features of high-definition-image content: (1) a stream manager for enabling simultaneous handling of continuous flows of data (“streams”) between various hardware components and HDDs, and (2) an “AV-use File System” for assuring data transfer rate of image contents. Applying these two middleware solutions enables HDTV images to be handed simultaneously, reduces the processing cost of AV equipment, and offers high functionality.