// G711Codec.cpp: implementation of the G711Codec class.
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//
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//////////////////////////////////////////////////////////////////////
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#include "G711Codec.h"
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#include "G711Table.h"
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//////////////////////////////////////////////////////////////////////
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// Construction/Destruction
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//////////////////////////////////////////////////////////////////////
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G711Codec::G711Codec()
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{
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SetULaw();
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}
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G711Codec::~G711Codec()
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{
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}
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int
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G711Codec::Encode(void *input, int inputSizeBytes, void *output, int *outputSizeBytes)
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{
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char *dataIn = (char *)input;
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char *dataOut = (char *)output;
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if (*outputSizeBytes < inputSizeBytes/2)
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{
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*outputSizeBytes = 0;
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return -10;
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}
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else
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{
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unsigned char *compTable;
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if (GetCodecType() == CODECTYPE_ULAW)
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{
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compTable = ulaw_comp_table;
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}
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else
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{
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compTable = alaw_comp_table;
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}
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// convert the sample
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for (int i=0; i<inputSizeBytes; i+=2) {
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short input = *((short *)(dataIn + i));
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dataOut[i/2] = compTable[(input / 4) & 0x3fff];
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}
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*outputSizeBytes = inputSizeBytes / 2;
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}
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return 0;
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}
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int
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G711Codec::Decode(void *input, int inputSizeBytes, void *output, int *outputSizeBytes)
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{
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unsigned char *dataIn = (unsigned char *)input;
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short *dataOut = (short *)output;
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if (inputSizeBytes*2 > *outputSizeBytes)
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{
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*outputSizeBytes = 0;
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return -10;
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}
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else
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{
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short *expTable;
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if (GetCodecType() == CODECTYPE_ULAW)
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{
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expTable = ulaw_exp_table;
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}
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else
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{
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expTable = alaw_exp_table;
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}
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// convert the sample
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for (int i=0; i<inputSizeBytes; i++)
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{
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dataOut[i] = expTable[dataIn[i]];
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}
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*outputSizeBytes = inputSizeBytes * 2;
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}
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return 0;
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}
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