Changes between Version 15 and Version 16 of user_applications
- Timestamp:
- Nov 21, 2015, 2:43:05 PM (10 years ago)
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user_applications
v15 v16 175 175 == __mjpeg__ == 176 176 177 This multi-threaded application makes the decompression of a MJPEG bit-stream contained in a file .177 This multi-threaded application makes the decompression of a MJPEG bit-stream contained in a file, an display the stream of images on the Frame Buffer. 178 178 It illustrates the "multi pipe-line" parallelism. It uses the message passing programming model, on top of the POSIX threads API, and the MWMR communication middleware. 179 179 The application is described as a TCG (Task and Communication Graph), and all communications between threads uses MWMR channels. 180 180 Each pipeline decompress one complete image, and there is one pipe-line per cluster. 181 It uses the chained buffer DMA component to display the stream of decompressed images on the graphic display.181 It uses the chained buffer DMA component to display the stream of decompressed images.ç!!l:=m 182 182 It contains 6 types of threads (plus the "main" thread, that makes initialisation), and 7 types of MWMR communication channels: 183 183 * the TG thread dispatch the bit-stream to the pipeline. It is only mapped in cluster[0,0]. 184 184 * the 5 threads implementing the pipeline (DEMUX, VLD, IQZZ, IDCT, LIBU) are replicated in all clusters. 185 185 * the 7 MWMR channels are replicated in all clusters. 186 The image throughput is actually bounded by the TG task that cannot be parallelized. 186 187 187 188 The hardware constraints are the following … … 191 192 * It uses one TTY terminal shared by all tasks. 192 193 194 All parameters (number of images, depths of communication channels, debug variables) are defined in the [source:soft/giet_vm/applications/mjpeg/mjpeg.h mjpeg.h] file. 195 193 196 The source code can be found [source:soft/giet_vm/applications/mjpeg/mjpeg.c here], and the mapping is defined [source:soft/giet_vm/applications/mjpeg/mjpeg.py here].