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Forum Index : Microcontroller and PC projects : JPEG picture
| Author | Message | ||||
| teun Newbie  Joined: 17/01/2012 Location: NetherlandsPosts: 6 |
Hi iam new here and new with MM basic. I did order some prints by Olimex and they are realy looking great. I was wondering would it be possible to display a picture wich is stored on the SD card for a few seconds before running a program? Or somewhere in the running program? I hope my Englisch is good enough. Thanks in advance from Holland. |
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| Olimex Senior Member  Joined: 02/10/2011 Location: BulgariaPosts: 226 |
JPEG decompression require lot of memory and BASIC will not handle it but you can display BMP picture check this http://www.thebackshed.com/forum/forum_posts.asp?TID=4566&PN =1 |
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jwettroth Regular Member  Joined: 02/08/2011 Location: United StatesPosts: 71 |
JPEG decompression is too much for Basic but I was surprised to see that it really doesn't take that much memory or code to implment. I was surprised to see the following library, TcJpgDec poosted last year (see below). It seems like its not too far out for the hardware platform of MM though someone would have to link it in to the source, etc. One of my hacker heroes, Chan (http://www.elm-chan.org) has posted a JPEG decompressor on his great web site. Its written in C. It can fit in 4.5k of code space and needs 3K of RAM. It runs on 8 bit class CPU's, proably would be very comfortable on a PIC32! MM Color isn't here yet so the utility of it isn't clear, I guess you could look at B&W snaps, etc. Here are some specs- TJpgDec is a generic JPEG image decompressor module that highly optimized for small embedded systems. It works with very low memory consumption so that it can be incorporated into tiny microcontrollers, such as AVR, 8051, PIC, Z80, Cortex-M0 and etc. Features •Platform independent. Written in ANSI-C. •Easy to use master mode operation. •Fully re-entrant architecture. •Very small memory footprint: ◦3K bytes of RAM for work area. Independent of image dimensions. ◦4.5-9.5K bytes of ROM for text and constants. •Output format: ◦Scaling ratio: 1/1, 1/2, 1/4 or 1/8 selectable on decompression. ◦RGB format: RGB888 or RGB565 pre-configurable. John Wettroth |
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| Olimex Senior Member Joined: 02/10/2011 Location: BulgariaPosts: 226 |
what happened to Chan? his web seems to be down, I also enjoyed his projects |
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| jwettroth Regular Member Joined: 02/08/2011 Location: United StatesPosts: 71 |
Sorry- I inserted a www in the link- the proper link is: http://elm-chan.org/ Alive and well and doing amazing things still... Regards, John Wettroth |
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