GSMEFR

Decodes GSM enhanced full rate (GSMEFR) audio streams to int16 PCM data streams.

The function calling process is as follows:

Obtain the size of the memory to be applied for decoding (dstBufLen).
Initialize the HmppaGsmefrDecodePolicy_16s structure by calling HMPPA_Gsmefr_DecodeInit_8u16s.
Call the main function HMPPA_Gsmefr_Decode_8u16s for decoding.
Call HMPPA_Gsmefr_DecodeRelease_8u16s to release the memory allocated to the HmppaGsmefrDecodePolicy_16s structure.

The function interface is declared as follows:

Obtaining the size of the memory to be applied for decoding:
HmppResult HMPPA_Gsmefr_GetDecodeDstBufLen_8u16s(int32_t len, int32_t *dstBufLen);
Initialization:
HmppResult HMPPA_Gsmefr_DecodeInit_8u16s(HmppaGsmefrDecodePolicy_16s** policy);
Decoding:
HmppResult HMPPA_Gsmefr_Decode_8u16s(const uint8_t* src, int32_t srcLen, int16_t* dst, HmppaGsmefrDecodePolicy_16s* policy, int32_t* bytesConsumed, int64_t* bytesDecoded);
Release:
HmppResult HMPPA_Gsmefr_DecodeRelease_8u16s(HmppaGsmefrDecodePolicy_16s* policy);

Parameters

Parameter	Description	Value Range	Input/Output
policy (in the Init function)	Pointer to pointer to the GSMEFR Policy structure	Not null	Output
policy (in the main and release functions)	Pointer to the GSMEFR structure	Not null	Input
src	Pointer to the input data to be decoded	Not null	Input
srcLen	Length of the input data	Non-negative	Input
dst	Pointer to the output decoded data	Not null	Output
bytesConsumed	Pointer to the data stream length (in bytes) actually consumed for decoding	Not null	Output
bytesDecoded	Pointer to the data stream length (in bytes) of the actual decoded output	Nullable	Output
dstBufLen	Pointer to the required destination vector length (in duel-bytes)	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	Any of the input pointers is NULL.
HMPP_STS_SIZE_ERR	The value of srcLen is not a positive number.
HMPP_STS_SIZE_WRN	The src is not completely decoded.

Example

#include<stdlib.h>
#include<stdio.h>
#include"hmppa.h"
#define ONE_FRAME_GSM 31
#define ONE_FRAME_PCM 160
int main(int argc, char* argv[])
{
    if (argc <3) {
        printf("%s in.gsmefr out.pcm\n", argv[0]);
        return 0;
    }
    FILE *file =fopen(argv[1], "rb");
    if (file ==NULL) {
        printf("Open File %s Failed\n", argv[1]);
        return 0;
    }
    fseek(file, 0, SEEK_END);
    int32_t srcLen =ftell(file);
    int32_t dstLen;
    HMPPA_Gsmefr_GetDecodeDstBufLen_8u16s(srcLen, &dstLen);
    fseek(file, 0, SEEK_SET);
    unsigned char src[srcLen];
    short pcm[dstLen];
    HmppaGsmefrDecodePolicy_16s *policy;
    HMPPA_Gsmefr_DecodeInit_8u16s(&policy);
    FILE *out = fopen(argv[2], "wb");
    if (out == NULL) {
        printf("Open File %s Failed\n", argv[2]);
        return 0;
    }
    fread(src, sizeof(unsigned char), srcLen, file);
    int bytesConsumed;
    int64_t bytesDecoded;
    int res = HMPPA_Gsmefr_Decode_8u16s(src, srcLen, pcm, policy, &bytesConsumed, &bytesDecoded);
    HMPPA_Gsmefr_DecodeRelease_8u16s(policy);
    printf("bytesConsumed = %d, bytesDecoded = %d, res = %d\n", bytesConsumed, bytesDecoded, res);
    fwrite(pcm, sizeof(short), bytesDecoded / 2, out);
}

Output:

bytesConsumed = 4898, bytesDecoded = 50560, res = 0

Parent topic: Audio Decoding