Mosalina is an off-line process that uses a unique picture quality measure called PAR - Picture Appraisal Rating. This is a single-ended process...
Mosalina is an off-line process that uses a unique picture quality measure called PAR - Picture Appraisal Rating. This is a single-ended process that monitors the artefacts produced by MPEG compression while ignoring those from prior operations. This PAR assessment combined with reporting bitrate and other parameters provide the practical tools needed to measure MPEG-2 against quality and bit-budget targets.
Mosalina provides both standard and high definition MPEG-2 users with means of assessing picture compression quality. This emulates the conventional frame-by-frame ‘naked eye' method but is also repeatable and more reliable. It is cost-effective, automated and offers an easy way to quantitatively check compressed material against agreed standards. Any problem areas can be swiftly identified, analyzed and corrective measures taken early during the production process.
Subsequent analysis, made easy by the Stream Analyzer display, then shows the causes of any out-of-spec readings. These may be due to the MPEG coder or further up the chain. Here, common problems are noise or bad PAL/NTSC decoding on the input video to the MPEG-2 coder, which can be corrected by using the company's Prefix compression pre-processor. Bitrates can also shoot up because of the 3:2 pull-down sequence, used to map 24-frame film to 60 fields-per-second video, going out of step. For this the input material may need attention in an edit suite.
Running under Windows (95, 98 or NT) Mosalina works faster than real-time on most PCs working with SD MPEG (MP@ML or 4:2:2P@ML). The software-based component system can be tailored to users' needs. The Project Manager provides asset tracking and system coordination for the analysis of data. Batch processing for overnight work can be set using the Advanced package. The Stream Analyzer shows MPEG parameters down to picture level and allows playouts via a PCI decoder card. With Mosalina Expert, Transport and Program Stream de-multiplexing is possible for assessment of complex bitstream structures.
Snell & Wilcox, Inc., 2225 - 1 Martin Avenue, Santa Clara, CA 95050. Tel: 408-260-1000; Fax: 408-260-2800.