FFMPEG实现音频重采样

/******************************************************************************* Copyright (c) wubihe Tech. Co., Ltd. All rights reserved. -------------------------------------------------------------------------------- Date Created: 2014-10-25 Author: wubihe QQ:1269122125 Email:1269122125@qq.com Description: 代码实现音频重采样 把交叉存储的双声道立体声转换成平行存储的双声道 立体声 -------------------------------------------------------------------------------- Modification History DATE AUTHOR DESCRIPTION -------------------------------------------------------------------------------- ********************************************************************************/ #include <stdio.h> #define __STDC_CONSTANT_MACROS #ifdef _WIN32 //Windows extern "C" { #include "libavcodec/avcodec.h" #include "libavformat/avformat.h" #include "libswresample/swresample.h" }; #else //Linux... #ifdef __cplusplus extern "C" { #endif #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #ifdef __cplusplus }; #endif #endif int main() { static char*pFormatName[]= { "FMT_U8","FMT_S16","FMT_S32","FMT_FLT","FMT_DBL", "FMT_U8P","FMT_S16P","FMT_S32P","FMT_FLTP","FMT_DBLP" }; //原始PCM文件 FILE *pInputFile = fopen("huangdun_r48000_FMT_S16_c2.pcm", "rb"); uint64_t iInputLayout = AV_CH_LAYOUT_STEREO; int iInputChans = av_get_channel_layout_nb_channels(iInputLayout); AVSampleFormat eInputSampleFormat = AV_SAMPLE_FMT_S16; int iInputSampleRate = 48000; //转换后PCM文件 uint64_t iOutputLayout = AV_CH_LAYOUT_STEREO; int iOutputChans = av_get_channel_layout_nb_channels(iOutputLayout); AVSampleFormat eOutputSampleFormat = AV_SAMPLE_FMT_S16P; int iOutputSampleRate = 48000; bool bOutPutPlaner=true; char szOutFileName[256]={0}; sprintf(szOutFileName,"huangdun_r%d_%s_c%d.pcm",iOutputSampleRate,pFormatName[eOutputSampleFormat],iOutputChans); FILE *pOutputFile = fopen(szOutFileName, "wb"); //初始化转换上下文 SwrContext *pSwrCtx = swr_alloc_set_opts(NULL,iOutputLayout, eOutputSampleFormat, iOutputSampleRate, iInputLayout,eInputSampleFormat , iInputSampleRate,0, NULL); swr_init(pSwrCtx); //1帧数据样本数 int iFrameSamples = 1024; //保存转换后的数据 /*uint8_t **ppConvertData = (uint8_t**)calloc(iOutputChans,sizeof(*ppConvertData)); int iConvertLineSize = 0; int iConvertDataSize = av_samples_alloc(ppConvertData, &iConvertLineSize,iOutputChans, iFrameSamples,eOutputSampleFormat, 0);*/ //音频处理是以帧为单位处理的 //分配存储原始数据内存空间 int iRawLineSize = 0; int iRawBuffSize = av_samples_get_buffer_size(&iRawLineSize, iInputChans, iFrameSamples, eInputSampleFormat, 0); uint8_t *pRawBuff = (uint8_t *)av_malloc(iRawBuffSize); //原始数据保存在AVFrame结构体中 AVFrame* pRawframe = av_frame_alloc(); pRawframe->nb_samples = iFrameSamples; pRawframe->format = eInputSampleFormat; pRawframe->channels = iInputChans; //把分配内存挂到AVFrame结构体中 int iReturn = avcodec_fill_audio_frame(pRawframe, iInputChans, eInputSampleFormat, (const uint8_t*)pRawBuff, iRawBuffSize, 0); if(iReturn<0) { return -1; } // 存储转换后数据 int iConvertLineSize = 0; int iConvertBuffSize = av_samples_get_buffer_size(&iConvertLineSize, iOutputChans, iFrameSamples, eOutputSampleFormat, 0); uint8_t *pConvertBuff = (uint8_t *)av_malloc(iConvertBuffSize); //转换后数据保存在AVFrame结构体中 AVFrame* pConvertframe = av_frame_alloc(); pConvertframe->nb_samples = iFrameSamples; pConvertframe->format = eOutputSampleFormat; pConvertframe->channels = iOutputChans; iReturn = avcodec_fill_audio_frame(pConvertframe, iOutputChans, eOutputSampleFormat, (const uint8_t*)pConvertBuff, iConvertBuffSize, 0); if(iReturn<0) { return -1; } int iFrameNum =0; //读取一帧音频数据 int iRealRead = fread(pRawBuff, 1, iRawBuffSize, pInputFile); while(iRealRead>0) { //完成音频帧转换 swr_convert(pSwrCtx, (uint8_t**)pConvertframe->data, iFrameSamples ,(const uint8_t**)pRawframe->data, iFrameSamples ); if(bOutPutPlaner) { //只保存一个通道数据 便于分析 因为PCM工具不支持这种平行存储方式数据查看 //一般情况平行存储方式pConvertframe->data[i]为i声道数据pConvertframe->linesize[i] //为i声道长度,但是音频各个声道的数据长度是相同的，所以只有pConvertframe->linesize[0]表示长度， //其他pConvertframe->linesize[1]==0 fwrite(pConvertframe->data[0],pConvertframe->linesize[0],1,pOutputFile); } printf("Convert Frame :%d\n",++iFrameNum); iRealRead = fread(pRawBuff, 1, iRawBuffSize, pInputFile); } fclose(pInputFile); fclose(pOutputFile); av_free(pRawBuff); av_free(pConvertBuff); swr_free(&pSwrCtx); printf("Convert Success!!\n"); getchar(); return 0; }