#include "ltwrappr.h"
L_INT LJp2FileFormat::ExtractFramesBuffer(pInFileName, lpBuffer, puBufferSize, puFrames, uNumOfFrames)
L_TCHAR * pInFileName; |
/* name of the input file */ |
L_UCHAR ** lpBuffer; |
/* pointer to a pointer */ |
L_SIZE_T * puBufferSize; |
/* pointer to a variable to be updated */ |
L_UINT32 * puFrames; |
/* frames indices */ |
L_UINT32 uNumOfFrames; |
/* number of frames to be extracted */ |
Extracts the frames that are specified by puFrames from the input file and save them into a new JPEG 2000 file in a memory buffer that is allocated by the function contains only the extracted frames headers and codestreams directly not through decompressing/compressing process.
Parameter |
Description |
pInFileName |
Character string that contains the name of the JPEG 2000 file to extract frames from it. |
lpBuffer |
Pointer to a pointer to be updated with an array of bytes that contains a JPEG 2000 file with extracted frames only. You must free this buffer by calling the Windows LocalFree() function. |
puBufferSize |
Address of a variable to be updated with the size of the memory buffer in bytes. |
puFrames |
Array of unsigned integers specifies the indices of the frames to be extracted from the input JPEG 2000 file. All indices shall be 0-based. If any frames index is out the frames number the function will return ERROR_INV_PARAMETER. |
uNumOfFrames |
Number of frames to be extracted. This field specifies the size of puFrames array. |
Returns
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
LJp2FileFormat::ExtractFramesBuffer extracts the specified frames from the input file and save them into a new JPEG 2000 file in a memory buffer that is allocated by the function contains only the extracted frames headers and codestreams directly not through decompressing/compressing process so it saves processor time and memory. This function is very suitable to server application where multiple clients request specific frames of a JPEG 2000 file so instead of decompressing then compressing the frames this function copies only the needed frames data to generate them and saves the data into a new JPEG 2000 file in a memory buffer.
Required DLLs and Libraries
LTJP2 For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application. |
Win32, x64.
See Also
Example
This example extracts a frame from JPX file.
#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName L_INT LJp2FileFormat__ExtractFramesBufferExample(L_UINT8** lpOutBuffer, L_SIZE_T * puSize) { LJp2FileFormat Engine; L_JP2_FILEINFO Jp2FileInfo; L_UINT32 puFrames[1]; L_INT nRet = 0; *lpOutBuffer = NULL; *puSize = 0; Jp2FileInfo.uStructSize = sizeof(L_JP2_FILEINFO); nRet = Engine.GetFileInfo(MAKE_IMAGE_PATH(TEXT("image1.jpx")),&Jp2FileInfo); if(nRet != SUCCESS) return nRet; if(Jp2FileInfo.uNumOfFrames < 2) return 0; /*Extract the second frame*/ puFrames[0] = 1; nRet = Engine.ExtractFramesBuffer(MAKE_IMAGE_PATH(TEXT("image1.jpx")), lpOutBuffer, puSize, puFrames, 1); if(nRet != SUCCESS) return nRet; /*Free File Info structure*/ nRet = Engine.FreeFileInfo( &Jp2FileInfo); if(nRet != SUCCESS) return nRet; return SUCCESS; }