Regarding Image re sizing using Tiva c series MCU and Keil as IDE.

User 10799357

Hi all, I Sreenivasa, new to embedded and I am writing a application that needs to re size an image(Jpeg format) and these are my requirements: * C * Keil as ide. * Image format is JPEG to JPEG. So for I tried with the open source code in the below link http://code.google.com/p/picojpeg/ It works fine but it needs more than 32K of memory allocation, but my MCU is having only 32k of RAM. Any help is appreciated. thanks Srini

CPallini

From the very picojpeg page[^]:

Optimized for minimal memory consumption: Uses only ~2.3KB of work memory.

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User 10799357

Pallini, They said the code memory consumption 2.3kb, not the code uses. actually while resizing an image of 1MB file, it reduces the size by taking the first pixel of each 8x8 block, so for that they will allocate the size of >32 kb of memory. thanks srini

CPallini

As far as I can understand you haven't to keep the whole image in RAM, have you?

THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite

User 10799357

hi CPallini, Actually for using malloc we need to allocate heap space in startup.s file, here its allowing only 1000k of memory and if I enter 2000k it will throw error as "there is no space in execution region", so when it try to access the memory at 35k it will show error, below is the code where it is getting stuck. pImage = (uint8 *)malloc(row_pitch * decoded_height);// here the size of allocation is >32kb. if (!pImage) { fclose(g_pInFile); return NULL; } row_blocks_per_mcu = image_info.m_MCUWidth >> 3; col_blocks_per_mcu = image_info.m_MCUHeight >> 3; for ( ; ; ) { int y, x; uint8 *pDst_row; status = pjpeg_decode_mcu(); if (status) { if (status != PJPG_NO_MORE_BLOCKS) { printf("pjpeg_decode_mcu() failed with status %u\n", status); free(pImage); fclose(g_pInFile); return NULL; } break; } if (mcu_y >= image_info.m_MCUSPerCol) { free(pImage); fclose(g_pInFile); return NULL; } if (reduce) { // In reduce mode, only the first pixel of each 8x8 block is valid. pDst_row = pImage + mcu_y * col_blocks_per_mcu * row_pitch + mcu_x * row_blocks_per_mcu * image_info.m_comps; if (image_info.m_scanType == PJPG_GRAYSCALE) { *pDst_row = image_info.m_pMCUBufR[0]; } else { uint y, x; for (y = 0; y < col_blocks_per_mcu; y++) { uint src_ofs = (y * 128); for (x = 0; x < row_blocks_per_mcu; x++) { pDst_row[0] = image_info.m_pMCUBufR[src_ofs]; // Here the error occurs. pDst_row[1] = image_info.m_pMCUBufG[src_ofs]; pDst_row[2] = image_info.m_pMCUBufB[src_ofs]; pDst_row += 3; src_ofs += 64; } pDst_row += row_pitch - 3 * row_blocks_per_mcu; } } } mcu_x++; if (mcu_x == image_info.m_MCUSPerRow) { mcu_x = 0; mcu_y++; } } fclose(g_pInFile); *x = decoded_width; *y = decoded_height; *comps = image_info.m_comps; return pImage; thanks srini

CPallini

Am I missing something? The library author claims: "Written entirely in C, no reliance at all on the C run-time library (it includes no headers other than picojpeg.h), and does not use any dynamic memory allocation."

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User 10799357

Hi pallini, I have used visual C++ 2008 express edition to execute the code and works fine, Since we are using Kiel as our IDE I did some minor changes. Yes only one header file(picojpeg.h) and they have used malloc in jpg2tga.c file

CPallini

Member 10833501 wrote:

they have used malloc in jpg2tga.c file

They? jpg2tga? Quoting again 'them':

picojpeg is a public domain JPEG decompressor written in plain C in a single source file picojpeg.c and a single header picojpeg.h"

and actually there is no malloc in picojpeg.c file.

THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite

User 10799357

hi pallini, Source package is having 2 source files 1) picojpeg.c and jpg2tga.c For your reerence I am attaching the link again here ">http://code.google.com/p/picojpeg/" thanks srini

CPallini

jpg2tga.cpp is not actually part of the library. It is an example program. However, if you really need such a functionality you could try to modify the code (if possible) to fit your needs. Another option could be using an external (serial) RAM.

THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite