G726

Decodes G726 audio data streams into the PCM format. Big-endian and little-endian bit stream formats are supported.

The function calling process is as follows:

Obtain the size of the memory to be applied for decoding (dstBufLen).
Initialize the HmppaG726DecodePolicy_16s by calling HMPPA_G726_DecodeInit_8u16s.
Call the main function HMPPA_G726_Decode_8u16s.
Call HMPPA_G726_DecodeRelease_8u16s to release the memory allocated to the HmppaG726DecodePolicy_16s structure.

The function interface is declared as follows:

Obtaining the size of the memory to be applied for decoding:
HmppResult HMPPA_G726_GetDecodeDstBufLen_8u16s(int32_t len, int32_t *dstBufLen, HmppSpchBitRate rate);
Initialization:
HmppResult HMPPA_G726_DecodeInit_8u16s(HmppSpchBitRate rate, int32_t littleEndian, HmppaG726DecodePolicy_16s **policy);
Decoding:
HmppResult HMPPA_G726_Decode_8u16s(const uint8_t *src, int32_t len, int16_t *dst, HmppaG726DecodePolicy_16s *policy, int32_t *bytesConsumed, int64_t *bytesDecoded);
Release:
HmppResult HMPPA_G726_DecodeRelease_8u16s(HmppaG726DecodePolicy_16s *policy);

Parameters

Parameter	Description	Value Range	Input/Output
rate	Bit rate of the G726 audio stream	HMPP_SPCHBR_16000, HMPP_SPCHBR_24000, HMPP_SPCHBR_32000, or HMPP_SPCHBR_40000	Input
littleEndian	Endian mode of the G726 stream	0: big endian 1: little endian	Input
src	Pointer to the G726 stream to be decoded	Not null	Input
len	Length of the G726 stream to be decoded, in bytes	(0, INT_MAX]	Input
dst	Pointer to the destination vector	Not null	Output
policy	Pointer to the special structure	Not null	Input/Output
bytesConsumed	Pointer to the data stream length (in bytes) actually consumed for decoding	[0, len]	Output
bytesDecoded	Pointer to the data stream length (in bytes) of the actual decoded output	[0, Theoretical output data stream length after decoding]	Output
dstBufLen	Length (in duel-bytes) required to point to the destination vector	Not null	Output

Return Value

Success: HMPP_STS_NO_ERR
Failure: An error code is returned.

Error Codes

Error Code	Description
HMPP_STS_NULL_PTR_ERR	The value of src, dst, or policy is NULL.
HMPP_STS_SIZE_ERR	The value of len is less than or equal to 0.
HMPP_STS_BAD_ARG_ERR	A member of the rate or policy structure is invalid.
HMPP_STS_MALLOC_FAILED	Memory allocation failed.
HMPP_STS_SIZE_WRN	The product of len x 8 is not an integral multiple of the number of bits at each sampling point.

Example

#include <stdio.h>
#include <stdlib.h>
#include "hmpp.h"
#define AUDIO_INBUF_SIZE 20480
#define BIG_ENDIAN_G726 0
int main(int argc, char **argv)
{
    if (argc <= 3) {
        fprintf(stderr, "Usage: %s <bitrates index> <input file> <output file>\n", argv[0]);
        exit(0);
    }
    const char *outFilename, *inFilename;
    int32_t bitrate = atoi(argv[1]);
    inFilename = argv[2];
    outFilename = argv[3];
    uint8_t *data;
    int32_t dataSize;
    int32_t bytesConsumered = 0;
    int64_t bytesDecoded = 0;
    FILE *inFile = fopen(inFilename, "rb");
    if (NULL == inFile) {
        printf("%s:[%d] open %s file failed\n", __FUNCTION__, __LINE__, inFilename);
        return -1;
    }
    FILE *outFile = fopen(outFilename, "wb");
    if (NULL == outFile) {
        printf("%s:[%d] open %s file failed\n", __FUNCTION__, __LINE__, outFilename);
        return -1;
    }
    HmppaG726DecodePolicy_16s *policy;
    HmppResult result = HMPPA_G726_DecodeInit_8u16s((HmppSpchBitRate)bitrate, BIG_ENDIAN_G726, &policy);
    if (result != HMPP_STS_NO_ERR) {
        printf("HMPPA_G729_DecodeInit_8u16s return : %d\n", result);
    }
    fseek(inFile, 0, SEEK_END);
    int32_t srcLen = ftell(inFile);
    fseek(inFile, 0, SEEK_SET);
    int32_t dstLen;
    HMPPA_G726_GetDecodeDstBufLen_8u16s(srcLen, &dstLen, (HmppSpchBitRate)bitrate);
    uint8_t *inBuf = HMPP_Malloc(srcLen);
    int16_t *outBuf = (int16_t *)HMPP_Malloc(dstLen * sizeof(int16_t));
    fread(inBuf, sizeof(uint8_t), srcLen, inFile);
    dataSize = srcLen;
    result = HMPPA_G726_Decode_8u16s(inBuf, dataSize, outBuf, policy, &bytesConsumered, &bytesDecoded);
    fwrite(outBuf, 1, bytesDecoded, outFile);
    printf("HmppResult: %d, bytesConsumed: %d, bytesDecoded: %d\n", result, bytesConsumered, bytesDecoded);
    HMPPA_G726_DecodeRelease_8u16s(policy);
    HMPP_Free(inBuf);
    HMPP_Free(outBuf);
    fclose(inFile);
    fclose(outFile);
    return 0;
}

Output:

HmppResult: 0, bytesConsumed: 533504, bytesDecoded: 4268032

Parent topic: Audio Decoding