FFMPEG实现PCM编码AAC和MP3(采用封装格式实现)

/******************************************************************************* 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PCM编码AAC,MP3格式 -------------------------------------------------------------------------------- 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 #define INPUT_FILE_NAME ("huangdun_r48000_FMT_S16_c2.pcm") //输出文件前缀 #define OUTPUT_FILE_NAME_PREFIX ("huangdun") //输出文件后缀 //#define OUTPUT_FILE_NAME_SUFFIX ("aac") //输出文件后缀 #define OUTPUT_FILE_NAME_SUFFIX ("mp3") //输出文件比特率 该值越大 音频质量越好 音质损失越小 #define OUTPUT_FILE_BIT_RATE (64000) int flush_encoder(AVFormatContext *fmt_ctx,unsigned int stream_index) { int ret; int got_frame; AVPacket enc_pkt; if (!(fmt_ctx->streams[stream_index]->codec->codec->capabilities &CODEC_CAP_DELAY)) return 0; while (1) { enc_pkt.data = NULL; enc_pkt.size = 0; av_init_packet(&enc_pkt); //输入视频帧为NULL ret = avcodec_encode_audio2 (fmt_ctx->streams[stream_index]->codec, &enc_pkt,NULL, &got_frame); av_frame_free(NULL); if (ret < 0) break; if (!got_frame) { ret=0; break; } printf("Flush Encoder: Succeed to encode 1 frame!\tsize:%5d\n",enc_pkt.size); /* mux encoded frame */ ret = av_write_frame(fmt_ctx, &enc_pkt); if (ret < 0) break; } return ret; } 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" }; //各种不同格式对应字节数 static int mapSampleBytes[AV_SAMPLE_FMT_NB] ={1,2,4,4,8,1,2,4,4,8}; //PCM原始数据格式 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; //不同样本格式长度 int iInputSampleBytes = mapSampleBytes[eInputSampleFormat]; //PCM需要重采样的格式 部分编码器不支持原始PCM的数据格式如MP3 uint64_t iOutputLayout = AV_CH_LAYOUT_STEREO; int iOutputChans = av_get_channel_layout_nb_channels(iOutputLayout); AVSampleFormat eOutputSampleFormat ; int iOutputSampleRate = 48000; if(strcmp(OUTPUT_FILE_NAME_SUFFIX,"aac") == 0) { eOutputSampleFormat = AV_SAMPLE_FMT_S16; } else if(strcmp(OUTPUT_FILE_NAME_SUFFIX,"mp3") == 0) { //MP3不支持AV_SAMPLE_FMT_S16这种格式 eOutputSampleFormat = AV_SAMPLE_FMT_S16P; } else { } //编码样本长度 int iOutputSampleBytes = mapSampleBytes[eOutputSampleFormat]; //是否需要重采样 bool bNeedResample = false; if(eInputSampleFormat != eOutputSampleFormat) { bNeedResample = true; } //是否平面存储结构 bool bPlanner = false; if((eOutputSampleFormat>=AV_SAMPLE_FMT_U8P) &&(eOutputSampleFormat<=AV_SAMPLE_FMT_DBLP)) { bPlanner = true; } //打开输入文件 FILE *pInputFile = fopen("huangdun_r48000_FMT_S16_c2.pcm", "rb"); if(pInputFile == NULL) { } //打开输出文件 char szOutFileName[256]={0}; sprintf(szOutFileName,"%s_br%d_sr%d.%s",OUTPUT_FILE_NAME_PREFIX,OUTPUT_FILE_BIT_RATE,iOutputSampleRate,OUTPUT_FILE_NAME_SUFFIX); FILE *pOutputFile = fopen(szOutFileName, "wb"); //打开中间测试文件 char szTempFileName[256]={0}; sprintf(szTempFileName,"%s_sr%d_c1.pcm",OUTPUT_FILE_NAME_PREFIX,iOutputSampleRate); FILE *pTempFile = fopen(szTempFileName, "wb"); int iReturn; ///////////编码器操作//////////////////////////////// //注册所有编解码器 av_register_all(); //封装格式上下文 AVFormatContext中有AVInputFormat和AVOutputFormat //解复用时avformat_open_input()初始化AVInputFormat，复用时用户自己初始化AVOutputFormat AVFormatContext* pFormatCtx; AVOutputFormat * fmt; //Method 1.分配一个封装格式 pFormatCtx = avformat_alloc_context(); //根据后缀名 填充 输出格式上下文 fmt = av_guess_format(NULL, szOutFileName, NULL); pFormatCtx->oformat = fmt; //Method 2. //avformat_alloc_output_context2(&pFormatCtx, NULL, NULL, out_file); //fmt = pFormatCtx->oformat; //添加一个流 AVStream *audio_st = avformat_new_stream(pFormatCtx, 0); if (audio_st==NULL) { return -1; } //添加一个输出路径 if (avio_open(&pFormatCtx->pb,szOutFileName, AVIO_FLAG_READ_WRITE) < 0) { printf("Failed to open output file!\n"); return -1; } //Show some information 日志信息 av_dump_format(pFormatCtx, 0, szOutFileName, 1); //初始化编码器相关结构体 获取输出流中的编码上下文 AVCodecContext* pCodecCtx = audio_st->codec; pCodecCtx->codec_id = fmt->audio_codec ; pCodecCtx->codec_type = AVMEDIA_TYPE_AUDIO ; //立体声 pCodecCtx->channel_layout = iOutputLayout ; pCodecCtx->channels = iOutputChans ; //编码比特率 AAC支持多种比特率 一般比特率越高 视频质量越好 需要传输带宽越大 pCodecCtx->bit_rate = OUTPUT_FILE_BIT_RATE; pCodecCtx->sample_rate = iOutputSampleRate; //PCM样本深度为AV_SAMPLE_FMT_S16 但不是所有格式的编码都支持这种格式 pCodecCtx->sample_fmt = eOutputSampleFormat; //编码器 AVCodec* pCodec = avcodec_find_encoder(pCodecCtx->codec_id); if (!pCodec) { printf("Can not find encoder!\n"); return -1; } //打开解码器 有可能失败 -22 错误，原因不同的编码格式支持的样本格式不一样 //如封装AAC格式样本格式是AV_SAMPLE_FMT_FLT，打开就出错 if ((iReturn = avcodec_open2(pCodecCtx, pCodec,NULL)) < 0) { printf("Failed to open encoder :[%d]!\n",iReturn); return -1; } //重采用上下文 SwrContext *pSwrCtx = NULL; //原始数据帧 AVFrame* pRawframe = NULL; //原始帧一Planer的大小 非平面分布的情况就是缓存总大小 int iRawLineSize = 0; //原始帧缓存大小 int iRawBuffSize = 0; //原始帧缓存 uint8_t *pRawBuff= NULL; //重采样后数据帧 AVFrame* pConvertframe = NULL; //重采样后一Planer的大小 int iConvertLineSize = 0; //重采样后缓存大小 int iConvertBuffSize = 0; //重采样后帧缓存 uint8_t *pConvertBuff = NULL; //1帧数据样本数 int iFrameSamples = pCodecCtx->frame_size; // 存储原始数据 iRawLineSize = 0; iRawBuffSize = av_samples_get_buffer_size(&iRawLineSize, iInputChans, iFrameSamples, eInputSampleFormat, 0); pRawBuff = (uint8_t *)av_malloc(iRawBuffSize); //原始数据保存在AVFrame结构体中 pRawframe = av_frame_alloc(); pRawframe->nb_samples = iFrameSamples; pRawframe->format = eInputSampleFormat; pRawframe->channels = iInputChans; iReturn = avcodec_fill_audio_frame(pRawframe, iInputChans, eInputSampleFormat, (const uint8_t*)pRawBuff, iRawBuffSize, 0); if(iReturn<0) { return -1; } if(bNeedResample) { pSwrCtx = swr_alloc_set_opts(NULL,iOutputLayout, eOutputSampleFormat, iOutputSampleRate, iInputLayout,eInputSampleFormat , iInputSampleRate,0, NULL); swr_init(pSwrCtx); // 存储转换后数据 iConvertLineSize = 0; iConvertBuffSize = av_samples_get_buffer_size(&iConvertLineSize, iOutputChans, iFrameSamples, eOutputSampleFormat, 0); pConvertBuff = (uint8_t *)av_malloc(iConvertBuffSize); //转换后数据保存在AVFrame结构体中 pConvertframe = av_frame_alloc(); pConvertframe->nb_samples = iFrameSamples; pConvertframe->format = eOutputSampleFormat; pConvertframe->channels = iOutputCh