基于FFMPEG+SDL2播放音频

#if 0 #include <stdio.h> #include <stdlib.h> #include <string.h> #define __STDC_CONSTANT_MACROS #ifdef _WIN32 //Windows extern "C" { #include "libavcodec/avcodec.h" #include "libavformat/avformat.h" #include "libswresample/swresample.h" #include "SDL2/SDL.h" }; #else //Linux... #ifdef __cplusplus extern "C" { #endif #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #include <libswresample/swresample.h> #include <SDL2/SDL.h> #ifdef __cplusplus }; #endif #endif //#define debug_msg(fmt, args...) printf("--->[%s,%d] " fmt "\n\n", __FUNCTION__, __LINE__, ##args) #define MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio //48000 * (32/8) unsigned int audioLen = 0; unsigned char *audioChunk = NULL; unsigned char *audioPos = NULL; void fill_audio(void * udata, Uint8 * stream, int len) { SDL_memset(stream, 0, len); if (audioLen == 0) return; len = (len>audioLen?audioLen:len); SDL_MixAudio(stream,audioPos,len,SDL_MIX_MAXVOLUME); audioPos += len; audioLen -= len; } int test_audio_2_play() { AVFormatContext *pFortCtx = NULL; AVCodecContext *pCodecCtx = NULL; AVCodec *pCodec = NULL; AVPacket *pPkt = NULL; AVFrame*pFrame = NULL; struct SwrContext *pSwrCtx = NULL; SDL_AudioSpec wantSpec; //FILE* outFile = fopen("output.pcm", "wb"); char inFile[] = "skycity1.mp3"; int ret = -1; int audioIndex = -1; int i = 0; int got_picture = -1; uint64_t out_chn_layout = AV_CH_LAYOUT_STEREO; //通道布局 输出双声道 enum AVSampleFormat out_sample_fmt=AV_SAMPLE_FMT_S16; //声音格式 int out_sample_rate=44100; //采样率 int out_nb_samples = -1; int out_channels = -1; //通道数 int out_buffer_size = -1; //输出buff unsigned char *outBuff = NULL; uint64_t in_chn_layout = -1; //通道布局 struct SwrContext *au_convert_ctx; av_register_all(); pFortCtx = avformat_alloc_context(); if (avformat_open_input(&pFortCtx, inFile, NULL, NULL) != 0) //open input file and read data into buf { printf("avformat_open_input error!\n"); ret = -1; goto ERR_1; } if (avformat_find_stream_info(pFortCtx, NULL) < 0) //find stream some info { printf("avformat_find_stream_info error!\n"); ret = -1; goto ERR_1; } /* find audio index */ for (i = 0; i < pFortCtx->nb_streams; i++) { if (pFortCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO) { audioIndex = i; break; } } if (-1 == audioIndex) { printf("can not find audio index!\n"); ret = -1; goto ERR_1; } printf("------>audioIndex is %d\n", audioIndex); pCodecCtx = pFortCtx->streams[audioIndex]->codec; pCodec = avcodec_find_decoder(pCodecCtx->codec_id); if (NULL == pCodec) { printf("can not find decoder!\n"); ret = -1; goto ERR_1; } if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) { printf("Could not open codec.\n"); ret = -1; goto ERR_1; } if (NULL == (pPkt = (AVPacket *)av_malloc(sizeof(AVPacket)))) { printf("AV malloc failure.\n"); ret = -1; goto ERR_2; } //out parameter out_nb_samples = pCodecCtx->frame_size; out_channels = av_get_channel_layout_nb_channels(out_chn_layout); out_buffer_size = av_samples_get_buffer_size(NULL, out_channels, out_nb_samples, out_sample_fmt, 1); outBuff = (unsigned char *)av_malloc(MAX_AUDIO_FRAME_SIZE*2); //双声道 printf("-------->out_buffer_size is %d\n",out_buffer_size); in_chn_layout = av_get_default_channel_layout(pCodecCtx->channels); pFrame = av_frame_alloc(); //SDL wantSpec.freq = out_sample_rate; wantSpec.format = AUDIO_S16SYS; wantSpec.channels = out_channels; wantSpec.silence = 0; wantSpec.samples = out_nb_samples; wantSpec.callback = fill_audio; wantSpec.userdata = pCodecCtx; if (SDL_OpenAudio(&wantSpec, NULL) < 0) { printf("can not open SDL!\n"); ret = -1; goto ERR_3; } //Swr au_convert_ctx=swr_alloc_set_opts(NULL, out_chn_layout, /*out*/ out_sample_fmt, /*out*/ out_sample_rate, /*out*/ in_chn_layout, /*in*/ pCodecCtx->sample_fmt , /*in*/ pCodecCtx->sample_rate, /*in*/ 0, NULL); swr_init(au_convert_ctx); SDL_PauseAudio(0); while(av_read_frame(pFortCtx, pPkt) >= 0) { if (pPkt->stream_index == audioIndex) { if (avcodec_decode_audio4(pCodecCtx, pFrame, &got_picture, pPkt) < 0) { printf("Error in decoding audio frame.\n"); ret = -1; break; } if (got_picture > 0) { swr_convert(au_convert_ctx,&outBuff, MAX_AUDIO_FRAME_SIZE,(const uint8_t **)pFrame->data , pFrame->nb_samples); //fwrite(outBuff, 1, out_buffer_size, outFile); while(audioLen > 0) SDL_Delay(1); audioChunk = (unsigned char *)outBuff; audioPos = audioChunk; audioLen = out_buffer_size; } } av_free_packet(pPkt); } SDL_CloseAudio(); SDL_Quit(); swr_free(&au_convert_ctx); ERR_3: av_free(outBuff); ERR_2: avcodec_close(pCodecCtx); avformat_close_input(&pFortCtx); ERR_1: avformat_free_context(pFortCtx); //fclose(outFile); return ret; } int main(int argc, char *argv[]) { //test_audio_2_PCM(); test_audio_2_play(); return 0; } #endif #if 1 //采用队列的方式 #include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #define __STDC_CONSTANT_MACROS #ifdef _WIN32 //Windows extern "C" { #include "libavcodec/avcodec.h" #include "libavformat/avformat.h" #include "libswresample/swresample.h" #include "SDL2/SDL.h" }; #else //Linux... #ifdef __cplusplus extern "C" { #endif #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #include <libswresample/swresample.h> #include <SDL2/SDL.h> #ifdef __cplusplus }; #endif #endif //#define debug_msg(fmt, args...) printf("--->[%s,%d] " fmt "\n\n", __FUNCTION__, __LINE__, ##args) #define MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio //48000 * (32/8) #define SDL_AUDIO_BUFFER_SIZE 1024 struct SwrContext *au_convert_ctx; int out_buffer_size = -1; //输出buff typedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond; } PacketQueue; PacketQueue audioq; void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->first_pkt = NULL; q->last_pkt = NULL; q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond(); } int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if(av_dup_packet(pkt) < 0) { return -1; } pkt1 = (AVPacketList *)av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) //队列为空 q->first_pkt = pkt1; else q->last_pkt->next = pkt1; //将当前链表的最后一个结点的next指向pkt1 q->last_pkt = pkt1; //将last_pkt指向最后一个结点，即pkt1 q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0; } int quit = 0; static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for(;;) { if(quit) { ret = -1; break; } pkt1 = q->first_pkt; //指向第一个结点，即取出第一个结点 if (pkt1) { q->first_pkt = pkt1->next; //即q->first_pkt = q->first_pkt->next 将第一个结点指向的下一个结点设置为first_pkt，可以理解为取出当前第一个结点 if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q-