[TOC]
开始前的BB
开始准备搞播放器了，还不知道怎么跟大佬们讲，头疼
老夫撸码就是一把梭
我们先粗暴的分为两个线程，一个负责音频的播放，一个负责视频的播放，根据之前的我们写过的东西，我们来改一改
在chapter_09/中新建两个类VideoThread和AudioThread，一个负责视频的解码，一个负责音频的解码，渲染的话我们新建一个AVRender，专门负责渲染以及窗口事件的管理
千言万语注释中
AVRender 渲染以及事件处理
AVRender.h
//// Created by MirsFang on 2019-03-25.//#ifndef LEARNFFMPEG_AVRENDER_H#define LEARNFFMPEG_AVRENDER_H#define WINDOW_WIDTH 1080#define WINDOW_HEIGHT 720#includeextern "C" {#include #include }/** 音视频渲染器 **/class AVRender {public: AVRender(); ~AVRender(); /** * 打开音频 * * @param sample_rate 采样率 * @param channel 通道数 * @param samples 采样大小(一帧的音频数据大小) * @param userdata 用户数据 * @param fillaudio 回调函数 */ void openAudio(int sample_rate, Uint8 channel, Uint16 samples, void *userdata, void (*fill_audio)(void *codecContext, Uint8 *stream, int len)); /** 循环获取事件 **/ void loopEvent(); /** 渲染视频 * * @param frame 视频帧 * @param duration 帧持续的时间 */ void renderVideo(AVFrame *frame,Uint32 duration);private: /** SDL窗口 **/ SDL_Window *window; /** SDL渲染者 **/ SDL_Renderer *render; /** SDL纹理 **/ SDL_Texture *texture; /** 显示区域 **/ SDL_Rect rect; /** 自己想要的输出的音频格式 **/ SDL_AudioSpec wantSpec;};#endif //LEARNFFMPEG_AVRENDER_H复制代码
AVRender.cpp
//// Created by MirsFang on 2019-03-25.//#include "AVRender.h"AVRender::AVRender() { //初始化SDL2 if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_EVENTS)) { std::cout << "[error] SDL Init error !" << std::endl; return; } //创建window window = SDL_CreateWindow("LearnFFmpeg", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, WINDOW_WIDTH, WINDOW_HEIGHT, SDL_WINDOW_OPENGL); if (!window) { std::cout << "[error] SDL Create window error!" << std::endl; return; } //创建Render render = SDL_CreateRenderer(window, -1, 0); //创建Texture texture = SDL_CreateTexture(render, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, WINDOW_WIDTH, WINDOW_HEIGHT); //初始化Rect rect.x = 0; rect.y = 0; rect.w = WINDOW_WIDTH; rect.h = WINDOW_HEIGHT;}AVRender::~AVRender() { SDL_CloseAudio(); SDL_Quit(); if(render)SDL_DestroyRenderer(render); if(texture)SDL_DestroyTexture(texture); if(window)SDL_DestroyWindow(window);}void AVRender::loopEvent() { SDL_Event event; for (;;) { SDL_PollEvent(&event); switch (event.type) { case SDL_KEYDOWN: switch (event.key.keysym.sym) { } break; case SDL_QUIT: return; default: break; } }}void AVRender::renderVideo(AVFrame *frame, Uint32 duration) { if (frame == nullptr)return; //上传YUV到Texture SDL_UpdateYUVTexture(texture, &rect, frame->data[0], frame->linesize[0], frame->data[1], frame->linesize[1], frame->data[2], frame->linesize[2] ); SDL_RenderClear(render); SDL_RenderCopy(render, texture, NULL, &rect); SDL_RenderPresent(render); SDL_Delay(duration);}void AVRender::openAudio(int sample_rate, Uint8 channel, Uint16 samples, void *userdata, void (*fill_audio)(void *, Uint8 *, int)) { //初始化SDL中自己想设置的参数 wantSpec.freq = sample_rate; wantSpec.format = AUDIO_S16SYS; wantSpec.channels = channel; wantSpec.silence = 0; wantSpec.samples = samples; wantSpec.callback = fill_audio; wantSpec.userdata = userdata; //打开音频之后wantSpec的值可能会有改动，返回实际设备的参数值 if (SDL_OpenAudio(&wantSpec, NULL) < 0) { std::cout << "[error] open audio error" << std::endl; return; } SDL_PauseAudio(0);}复制代码 VideoThread 视频解码
视频解码类VideoThread.h
//// Created by MirsFang on 2019-03-25.//#ifndef LEARNFFMPEG_VIDEOTHREAD_H#define LEARNFFMPEG_VIDEOTHREAD_H#include#include #include "AVRender.h"extern "C" {#include #include };/** 视频线程 **/class VideoThread {public: VideoThread(); ~VideoThread(); /** 设置视频路径 **/ void setUrl(const char *url); /** 设置渲染器 **/ void setRender(AVRender *render); /** 开始运行线程 **/ void start();private: AVFormatContext *format_context; AVCodecContext *codec_context; AVCodec *codec; AVPacket *packet; AVFrame *frame; const char *url; int video_index; pthread_t pid; pthread_mutex_t mutex; AVRender *avRender; double last_pts = 0; /** 帧间距同步 **/ bool is_interval_sync = true; static void *start_thread(void *arg); void run(); /** 初始化解码器 **/ void prepare_codec(); /** 解码数据帧 **/ void decodec_frame(); /** * 根据帧率获取显示时间 * @param frame_rate 帧率 * @return 需要显示的时长 */ Uint32 sync_frame_rate(double frame_rate); /** * 根据帧间隔获取一帧显示的时长 * @param timebase * @param pts 秒 * @return */ double sync_frame_interval(AVRational timebase, int pts);};#endif //LEARNFFMPEG_VIDEOTHREAD_H复制代码
VideoThread.cpp
//// Created by MirsFang on 2019-03-25.//#include "VideoThread.h"VideoThread::VideoThread() {}VideoThread::~VideoThread() { if (format_context != nullptr) avformat_close_input(&format_context); if (codec_context != nullptr) avcodec_free_context(&codec_context); if (packet != nullptr) av_packet_free(&packet); if (frame != nullptr) av_frame_free(&frame);}void VideoThread::start() { prepare_codec(); if (pthread_create(&pid, NULL, start_thread, (void *) this) != 0) { std::cout << "初始化视频线程失败!" << std::endl; return; }}void *VideoThread::start_thread(void *arg) { VideoThread *audioThread = (VideoThread *) arg; audioThread->run(); return nullptr;}void VideoThread::run() { std::cout << "视频线程运行中..." << std::endl; decodec_frame();}void VideoThread::setRender(AVRender *render) { this->avRender = render;}void VideoThread::setUrl(const char *url) { this->url = url;}void VideoThread::prepare_codec() { int retcode; //初始化FormatContext format_context = avformat_alloc_context(); if (!format_context) { std::cout << "[error] alloc format context error!" << std::endl; return; } //打开输入流 retcode = avformat_open_input(&format_context, url, nullptr, nullptr); if (retcode != 0) { std::cout << "[error] open input error!" << std::endl; return; } //读取媒体文件信息 retcode = avformat_find_stream_info(format_context, NULL); if (retcode != 0) { std::cout << "[error] find stream error!" << std::endl; return; } //分配codecContext codec_context = avcodec_alloc_context3(NULL); if (!codec_context) { std::cout << "[error] alloc codec context error!" << std::endl; return; } //寻找到视频流的下标 video_index = av_find_best_stream(format_context, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0); //将视频流的的编解码信息拷贝到codecContext中 retcode = avcodec_parameters_to_context(codec_context, format_context->streams[video_index]->codecpar); if (retcode != 0) { std::cout << "[error] parameters to context error!" << std::endl; return; } //查找解码器 codec = avcodec_find_decoder(codec_context->codec_id); if (codec == nullptr) { std::cout << "[error] find decoder error!" << std::endl; return; } //打开解码器 retcode = avcodec_open2(codec_context, codec, nullptr); if (retcode != 0) { std::cout << "[error] open decodec error!" << std::endl; return; } //初始化一个packet packet = av_packet_alloc(); //初始化一个Frame frame = av_frame_alloc();}void VideoThread::decodec_frame() { int sendcode = 0; //计算帧率 double frameRate = av_q2d(format_context->streams[video_index]->avg_frame_rate); //计算显示的时间 Uint32 display_time_ms = 0; if (!is_interval_sync) { display_time_ms = sync_frame_rate(frameRate); } //记录帧间延迟 clock_t start = 0, finish = 0; //读取包 while (av_read_frame(format_context, packet) == 0) { if (packet->stream_index != video_index)continue; //接受解码后的帧数据 while (avcodec_receive_frame(codec_context, frame) == 0) { /** * 如果开启帧间隔同步模式,那么是根据 * * 显示时长 = 当前帧 - 上一帧 - 单帧解码耗时 * * 可得出当前帧真正要显示的时间 * * **/ if (is_interval_sync) { //计算上一帧与当前帧的延时 display_time_ms = (Uint32) ( sync_frame_interval(format_context->streams[video_index]->time_base, frame->pts) * 1000); //帧解码结束时间 finish = clock(); double diff_time = (finish - start) / 1000; //减去帧间解码时差 帧解码开始时间 - 帧解码结束时间 if (display_time_ms > diff_time)display_time_ms = display_time_ms - (Uint32) diff_time; } //绘制图像 if (avRender)avRender->renderVideo(frame, display_time_ms); av_frame_unref(frame); //帧解码开始时间 start = clock(); } //发送解码前的包数据 sendcode = avcodec_send_packet(codec_context, packet); //根据发送的返回值判断状态 if (sendcode == 0) {// std::cout << "[debug] " << "SUCCESS" << std::endl; } else if (sendcode == AVERROR_EOF) { std::cout << "[debug] " << "EOF" << std::endl; } else if (sendcode == AVERROR(EAGAIN)) { std::cout << "[debug] " << "EAGAIN" << std::endl; } else { std::cout << "[debug] " << av_err2str(AVERROR(sendcode)) << std::endl; } av_packet_unref(packet); }}Uint32 VideoThread::sync_frame_rate(double frame_rate) { return 1 * 1000 / frame_rate;}double VideoThread::sync_frame_interval(AVRational timebase, int pts) { double display = (pts - last_pts) * av_q2d(timebase); last_pts = pts; std::cout << "pts : " << pts * av_q2d(timebase) << " -- display :" << display << std::endl; return display;}复制代码 AudioThread 音频解码
AudioThread
//// Created by MirsFang on 2019-03-25.//#ifndef LEARNFFMPEG_AUDIOTHREAD_H#define LEARNFFMPEG_AUDIOTHREAD_H#include#include extern "C" {#include #include #include };#include "AVRender.h"/** * 音频线程 */class AudioThread {public: AudioThread(); ~AudioThread(); void setUrl(const char *url); /** 开启线程 **/ void start(); /** 设置渲染器 **/ void setRender(AVRender *render);private: /** 重采样上下文 **/ SwrContext *convert_context; AVFormatContext *format_context; AVCodecContext *codec_context; AVCodec *codec; AVPacket *packet; AVFrame *frame; int audioIndex = -1; uint64_t out_chn_layout = AV_CH_LAYOUT_STEREO; //输出的通道布局 双声道 enum AVSampleFormat out_sample_fmt = AV_SAMPLE_FMT_S16; //输出的声音格式 int out_sample_rate = 44100; //输出的采样率 int out_nb_samples = -1; //输出的音频采样 int out_channels = -1; //输出的通道数 int out_buffer_size = -1; //输出buff大小 unsigned char *outBuff = NULL;//输出的Buffer数据 uint64_t in_chn_layout = -1; //输入的通道布局 pthread_t pid; pthread_mutex_t mutex; AVRender *av_render; const char *url; static void *start_thread(void *arg); void run(); /** 初始化解码器 **/ void prepare_codec();};#endif //LEARNFFMPEG_AUDIOTHREAD_H复制代码
AudioThread.cpp
//// Created by MirsFang on 2019-03-25.//#include "AudioThread.h"#define MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio 48000 * (32/8)//一帧PCM的数据长度unsigned int audioLen = 0;unsigned char *audioChunk = nullptr;//当前读取的位置unsigned char *audioPos = nullptr;/** 被SDL2调用的回调函数 当需要获取数据喂入硬件播放的时候调用 **/void fill_audio(void *codecContext, Uint8 *stream, int len) { //SDL2中必须首先使用SDL_memset()将stream中的数据设置为0 SDL_memset(stream, 0, len); if (audioLen == 0) return; len = (len > audioLen ? audioLen : len); //将数据合并到 stream 里 SDL_MixAudio(stream, audioPos, len, SDL_MIX_MAXVOLUME); //一帧的数据控制 audioPos += len; audioLen -= len;}AudioThread::AudioThread() {}AudioThread::~AudioThread() { if (format_context != nullptr) avformat_close_input(&format_context); if (codec_context != nullptr) avcodec_free_context(&codec_context); if (packet != nullptr) av_packet_free(&packet); if (frame != nullptr) av_frame_free(&frame); if (convert_context != nullptr) swr_free(&convert_context);}void AudioThread::start() { prepare_codec(); if (pthread_create(&pid, NULL, start_thread, (void *) this) != 0) { std::cout << "初始化音频线程失败!" << std::endl; return; }}void *AudioThread::start_thread(void *arg) { AudioThread *audioThread = (AudioThread *) arg; audioThread->run(); return nullptr;}void AudioThread::run() { std::cout << "音频线程已启动" << std::endl; //循环读取packet并且解码 int sendcode = 0; while (av_read_frame(format_context, packet) >= 0) { if (packet->stream_index != audioIndex)continue; //接受解码后的音频数据 while (avcodec_receive_frame(codec_context, frame) == 0) { swr_convert(convert_context, &outBuff, MAX_AUDIO_FRAME_SIZE, (const uint8_t **) frame->data, frame->nb_samples); //如果没有播放完就等待1ms while (audioLen > 0) SDL_Delay(1); //同步数据 audioChunk = (unsigned char *) outBuff; audioPos = audioChunk; audioLen = out_buffer_size; av_frame_unref(frame); } //发送解码前的包数据 sendcode = avcodec_send_packet(codec_context, packet); //根据发送的返回值判断状态 if (sendcode == 0) {// std::cout << "[debug] " << "SUCCESS" << std::endl; } else if (sendcode == AVERROR_EOF) { std::cout << "[debug] " << "EOF" << std::endl; } else if (sendcode == AVERROR(EAGAIN)) { std::cout << "[debug] " << "EAGAIN" << std::endl; } else { std::cout << "[debug] " << av_err2str(AVERROR(sendcode)) << std::endl; } av_packet_unref(packet); }}void AudioThread::setRender(AVRender *render) { this->av_render = render;}void AudioThread::prepare_codec() { int retcode; //初始化FormatContext format_context = avformat_alloc_context(); if (!format_context) { std::cout << "[error] alloc format context error!" << std::endl; return; } //打开输入流 retcode = avformat_open_input(&format_context, url, nullptr, nullptr); if (retcode != 0) { std::cout << "[error] open input error!" << std::endl; return; } //读取媒体文件信息 retcode = avformat_find_stream_info(format_context, NULL); if (retcode != 0) { std::cout << "[error] find stream error!" << std::endl; return; } //分配codecContext codec_context = avcodec_alloc_context3(NULL); if (!codec_context) { std::cout << "[error] alloc codec context error!" << std::endl; return; } //寻找到音频流的下标 audioIndex = av_find_best_stream(format_context, AVMEDIA_TYPE_AUDIO, -1, -1, NULL, 0); //将视频流的的编解码信息拷贝到codecContext中 retcode = avcodec_parameters_to_context(codec_context, format_context->streams[audioIndex]->codecpar); if (retcode != 0) { std::cout << "[error] parameters to context error!" << std::endl; return; } //查找解码器 codec = avcodec_find_decoder(codec_context->codec_id); if (codec == nullptr) { std::cout << "[error] find decoder error!" << std::endl; return; } //打开解码器 retcode = avcodec_open2(codec_context, codec, nullptr); if (retcode != 0) { std::cout << "[error] open decodec error!" << std::endl; return; } //初始化一个packet packet = av_packet_alloc(); //初始化一个Frame frame = av_frame_alloc(); /** ########## 获取实际音频的参数 ##########**/ //单个通道中的采样数 out_nb_samples = codec_context->frame_size; //输出的声道数 out_channels = av_get_channel_layout_nb_channels(out_chn_layout); //输出音频的布局 in_chn_layout = av_get_default_channel_layout(codec_context->channels); /** 计算重采样后的实际数据大小,并分配空间 **/ //计算输出的buffer的大小 out_buffer_size = av_samples_get_buffer_size(NULL, out_channels, out_nb_samples, out_sample_fmt, 1); //分配输出buffer的空间 outBuff = (unsigned char *) av_malloc(MAX_AUDIO_FRAME_SIZE * 2); //双声道 //初始化SDL中自己想设置的参数 if (av_render)av_render->openAudio(out_sample_rate, out_channels, out_nb_samples, codec_context, fill_audio); convert_context = swr_alloc_set_opts(NULL, out_chn_layout, out_sample_fmt, out_sample_rate, in_chn_layout, codec_context->sample_fmt, codec_context->sample_rate, 0, NULL); //初始化SwResample的Context swr_init(convert_context);}void AudioThread::setUrl(const char *url) { this->url = url;}复制代码 我们在Main方法中
#ifdef chapter_09 //实例化渲染器 AVRender* render = new AVRender(); //初始化视频线程 VideoThread *videoThread = new VideoThread(); videoThread->setRender(render); videoThread->setUrl(url); //初始化音频线程 AudioThread *audioThread = new AudioThread(); audioThread->setRender(render); audioThread->setUrl(url); //开启音视频线程 videoThread->start(); audioThread->start(); //事件循环 render->loopEvent();#endif复制代码
如果没错，那么就应该正常的播放视频了。。。
祝各位大佬们好运
未完持续 ...