AMJPEGEncoderfortheNOWtovisualizeandnavigateon

1、A MJPEG Encoder for the NOW to visualize and navigate on data-intensive scenariosJos Mara Gonzlez1The problemProblem: How to be able to monitor through interactive visualization enormous amounts of image data that are being treated in a remote (parallel) machine from an external box that controls th

2、e data process behavior.Two issues:link from the parallel machine to the controller is usually low bandwidth (at least parallel machine internal links)display performance2The solutionSolution: On-the-fly degradation (“downgrade”) of the data trading off visualization quality to permit the adaptation

3、 to the control box display performance and link bandwidth.Some example numbers:ATV: 1920 x1080, 30 fps, 1.5 B/pixel, 93 MB/s, cannot be pumped into a normal LANCIF at 30 fps, 4.6 MB/s neitherATV with MJPEG 20/1 compression (q75) plus frame decimation (7.5 fps) get possible bandwidth = 1 MB/s3More i

4、ssuesInteractivityScalability (no centralized coordination point) FlexibilitySolution: Parallelize the degradation process!4Parallelization5Parallel Architecture6An interesting applicationA virtual-reality system that permits a remote user to navigate on very large image assets (satellite, astronomi

5、cal, geographical, medical, ) interactively.The user asks for images depending on its position. The system reads the data needed and encodes it in parallel, obtaining a video stream that fits in the user link.7ImplementationThree kinds of processes:readersencodersmultiplexerUse of River, a data-flow

6、 programming environment and an I/O substrate for clusters of computers.8Implementation (cont.)Network of WorkstationsRiverReaderEncoderMux.Controlling scriptsRiver modules9Performance resultsDisk performance IJG JPEG Encoder performance 2-3 MB/sConfiguration n/n/1Be careful with ! (cleaner process)

7、10Performance results (cont.)TBDATVCIFQCIF11ConclusionsEfficient, scalable MJPEG encoder (1 MB/s of reading throughput per pair of nodes)Use of a parallel architecture to permit visualization of huge amounts of image data is an interesting tool to permit interactive monitoring of parallel machines.Design and development of a virtual-reality system based on the parallel MJPEG encoder12Future workOutput bandwidth adaptive to remote linkMPI implementation instead of RiverDisplay app. p