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L_Jp2ExtractFramesBufferMemory

#include "l_bitmap.h"

L_LTJP2_API L_INT EXT_FUNCTION L_Jp2ExtractFramesBufferMemory(hJp2, pBuffer, uBufferSize, lpBuffer, puBufferSize, puFrames, uNumOfFrames)

Extracts the frames that are specified by puFrames from the JPEG 2000 file in memory 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.

Parameters

L_HJP2 hJp2

JPEG 2000 engine handle that was created by the L_Jp2Create function.

L_UINT8 * pBuffer

Pointer to the JPEG 2000 file in memory to extract frames from it.

L_SIZE_T uBufferSize

Size of the in memory (in bytes).

L_UINT8 ** 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 GlobalFree() function.

L_SIZE_T * puBufferSize

Address of a variable to be updated with the size of the memory buffer in bytes.

L_UINT32 * 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.

L_UINT32 uNumOfFrames

Number of frames to be extracted. This field specifies the size of puFrames array.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

L_Jp2ExtractFramesBufferMemory extracts the specified frames from the JPEG 2000 file in memory 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
LTIMGEFX
LFJ2K
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64.

Functions

Topics

Example

This example extracts a frame from JPX file.

L_INT Jp2ExtractFramesBufferMemoryExample(L_UINT8* pFileBuffer, L_SIZE_T uFileSize, L_UINT8** lpFrameBuffer, L_SIZE_T * puFrameSize) 
{ 
   L_HJP2 hEngine; 
   L_JP2_FILEINFO Jp2FileInfo; 
   L_UINT32 puFrames[1]; 
    
   *lpFrameBuffer = NULL; 
   *puFrameSize = 0; 
 
   /*Create JPEG  2000 engine handle*/ 
   hEngine = L_Jp2Create(); 
 
   Jp2FileInfo.uStructSize = sizeof(L_JP2_FILEINFO); 
   L_Jp2GetFileInfoMemory(hEngine, pFileBuffer, uFileSize, &Jp2FileInfo); 
 
   /*Extract the second frame*/ 
   puFrames[0] = 0; 
 
   L_Jp2ExtractFramesBufferMemory(hEngine, pFileBuffer, uFileSize, lpFrameBuffer, puFrameSize, puFrames, 1); 
 
   /*Free File Info structure*/ 
   L_Jp2FreeFileInfo(hEngine, &Jp2FileInfo); 
   /*Destroy engine handle*/ 
   L_Jp2Destroy(hEngine); 
   return SUCCESS; 
}

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