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C API Reference - Video Methods


DBR_StartFrameDecoding

Start a new thread to decode barcodes from the inner frame queue with specific frame decoding setting passed in.

DBR_API int DBR_StartFrameDecoding (void* barcodeReader, const int maxQueueLength, const int maxResultQueueLength, const int width, const int height, const int stride, const ImagePixelFormat format, const char* pTemplateName)	

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in] maxQueueLength The max number of frames waiting for decoding.
[in] maxResultQueueLength The max number of frames whose results (text result/localization result) will be kept.
[in] width The width of the frame image in pixels.
[in] height The height of the frame image in pixels.
[in] stride The stride (or scan width) of the frame image.
[in] format The image pixel format used in the image byte array.
[in] pTemplateName The template name.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_FRAME_DECODING_THREAD_EXISTS; DBRERR_PARAMETER_VALUE_INVALID; DBRERR_NULL_POINTER.
You can call DBR_GetErrorString to get detailed error message.

Code Snippet

void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
int errorCode = DBR_StartFrameDecoding(barcodeReader, 2, 10, 1024, 720, 720, IPF_BINARY, "");
DBR_DestroyInstance(barcodeReader);

 

DBR_StartFrameDecodingEx

Start a new thread to decode barcodes from the inner frame queue with specific frame decoding setting defined in FrameDecodingParameters struct.

DBR_API int DBR_StartFrameDecodingEx (void* barcodeReader, FrameDecodingParameters parameters, const char* pTemplateName)	

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in] parameters The frame decoding parameters.
[in] pTemplateName The template name.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_FRAME_DECODING_THREAD_EXISTS; DBRERR_PARAMETER_VALUE_INVALID; DBRERR_NULL_POINTER.
You can call DBR_GetErrorString to get detailed error message.

Code Snippet

void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
FrameDecodingParameters parameters;
int errorCode = DBR_InitFrameDecodingParameters(barcodeReader, &parameters);
if(errorCode == DBR_OK)
{
    parameters.maxQueueLength = 3;
    parameters.maxResultQueueLength = 10;
    parameters.width = 20;
    parameters.height = 30;
    parameters.stride = 10;
    parameters.imagePixelFormat = IPF_GRAYSCALED;
    parameters.region.regionMeasuredByPercentage = 1;
    parameters.region.regionTop = 0;
    parameters.region.regionBottom = 100;
    parameters.region.regionLeft = 0;
    parameters.region.regionRight = 100;
    parameters.threshold = 0.1;
    parameters.fps = 0;
    int errorCode = DBR_StartFrameDecodingEx(barcodeReader, parameters, "");
    DBR_DestroyInstance(barcodeReader);
}

 

DBR_AppendFrame

Appends a frame image buffer to the inner frame queue.

DBR_API int DBR_AppendFrame (void* barcodeReader, unsigned char* pBufferBytes)

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in] pBufferBytes The array of bytes which contain the image data.

Return value

Returns the ID of the appended frame.

Code Snippet

void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
int frameId = DBR_AppendFrame(barcodeReader, pBufferBytes);
DBR_DestroyInstance(barcodeReader);

 

DBR_StopFrameDecoding

Stops the frame decoding thread created by DBR_StartFrameDecoding or DBR_StartFrameDecodingEx.

DBR_API int DBR_StopFrameDecoding (void* barcodeReader)

Parameters

[in] barcodeReader Handle of the barcode reader instance.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_STOP_DECODING_THREAD_FAILED.
You can call DBR_GetErrorString to get detailed error message.


Code Snippet

void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
int errorCode = DBR_StopFrameDecoding(barcodeReader);
DBR_DestroyInstance(barcodeReader);

 

DBR_InitFrameDecodingParameters

Initialize frame decoding parameters with default values.

DBR_API int DBR_InitFrameDecodingParameters (void* barcodeReader, FrameDecodingParameters* pParameters)	

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in,out] pParameters The frame decoding parameters.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_NULL_POINTER.
You can call DBR_GetErrorString to get detailed error message.

Code Snippet

void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
FrameDecodingParameters parameters;
int errorCode = DBR_InitFrameDecodingParameters(barcodeReader, &parameters);
if(errorCode == DBR_OK)
{
    parameters.maxQueueLength = 3;
    parameters.maxResultQueueLength = 10;
    parameters.width = 20;
    parameters.height = 30;
    parameters.stride = 10;
    parameters.imagePixelFormat = IPF_GRAYSCALED;
    parameters.region.regionMeasuredByPercentage = 1;
    parameters.region.regionTop = 0;
    parameters.region.regionBottom = 100;
    parameters.region.regionLeft = 0;
    parameters.region.regionRight = 100;
    parameters.threshold = 0.1;
    parameters.fps = 0;
}
DBR_DestroyInstance(barcodeReader);

 

DBR_SetErrorCallback

Set callback function to process errors generated during frame decoding.

DBR_API int DBR_SetErrorCallback (void* barcodeReader, CB_Error cbFunction, void* pUser)

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in] cbFunction Callback function.
[in] pUser Customized arguments passed to your function.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_FRAME_DECODING_THREAD_EXISTS.
You can call DBR_GetErrorString to get detailed error message.

Code Snippet

void ErrorFunction(int frameId, int errorCode, void * pUser)
{
    //TODO add your code for using error code
}
void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
DBR_SetErrorCallback(barcodeReader, ErrorFunction, NULL);
DBR_StartFrameDecoding(barcodeReader, 2, 10, 1024, 720, 720, IPF_BINARY, "");

 

DBR_SetTextResultCallback

Set callback function to process text results generated during frame decoding.

DBR_API int DBR_SetTextResultCallback (void* barcodeReader, CB_TextResult cbFunction, void* pUser)

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in] cbFunction Callback function.
[in] pUserCustomized arguments passed to your function.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_FRAME_DECODING_THREAD_EXISTS.
You can call DBR_GetErrorString to get detailed error message.

Code Snippet

void TextResultFunction(int frameId, TextResultArray *pResults, void * pUser)
{
    //TODO add your code for using test results
}
void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
DBR_SetTextResultCallback(barcodeReader, TextResultFunction, NULL);
DBR_StartFrameDecoding(barcodeReader, 2, 10, 1024, 720, 720, IPF_BINARY, "");

 

DBR_SetIntermediateResultCallback

Set callback function to process intermediate results generated during frame decoding.

DBR_API int DBR_SetIntermediateResultCallback (void* barcodeReader, CB_IntermediateResult cbFunction, void* pUser)	

Parameters

[in] barcodeReader Handle of the barcode reader instance.
[in] cbFunction Callback function.
[in] pUser Customized arguments passed to your function.

Return value

Returns error code. Possible return(s): DBR_OK; DBRERR_FRAME_DECODING_THREAD_EXISTS. You can call DBR_GetErrorString to get detailed error message.

Code Snippet

void IntermediateResultFunction(int frameId, IntermediateResultArray *pResults, void * pUser)
{
    //TODO add your code for using intermediate results
}
void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
PublicRuntimeSettings settings;
int errorCode = DBR_GetRuntimeSettings(barcodeReader, &settings);
settings.intermediateResultTypes = IRT_ORIGINAL_IMAGE | IRT_COLOUR_CLUSTERED_IMAGE | IRT_COLOUR_CONVERTED_GRAYSCALE_IMAGE;
char errorMessage[256];
DBR_UpdateRuntimeSettings(barcodeReader, &settings, errorMessage, 256);
DBR_SetIntermediateResultCallback(barcodeReader, IntermediateResultFunction, NULL);
DBR_StartFrameDecoding(barcodeReader, 2, 10, 1024, 720, 720, IPF_BINARY, "");

 

DBR_GetLengthOfFrameQueue

Get length of current inner frame queue.

DBR_API int DBR_GetLengthOfFrameQueue (void* barcodeReader)

Parameters

[in] barcodeReader Handle of the barcode reader instance.

Return value

Returns the length of the inner frame queue.


Code Snippet

void* barcodeReader = DBR_CreateInstance();
DBR_InitLicense(barcodeReader, "t0260NwAAAHV***************");
int frameLength = DBR_GetLengthOfFrameQueue(barcodeReader);
DBR_DestroyInstance(barcodeReader);

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Version 7.5

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