目录
这次的代码主要解决了如下问题
存在的问题
与之前版本的差异点
关于time_base的知识
video显示线程内等待audio的代码
audio线程计算 audio_clock的代码
完整的代码
在上一篇文章中FFMPEG学习（三）ffmpeg+SDL2.0制作简单的视频播放器（图像+声音），我们的代码里播放了MP4文件的音频跟视屏，但是会有音频晚于视屏的问题。这里我们进进行修改，使得视屏的播放基于音频播放时间进行同步
这次的代码主要解决了如下问题
1、播放完成无法自动结束的问题
2、音频与视屏播放无法同步时间问题
存在的问题
1、概率性执行完成之后发生段错，gdb调试暂时没有结论。后续再优化
2、只考虑了音频比视频慢的情况处理，如果银屏比视频更快这个情况，是不是也要在audio线程内等待？
3、代码内视屏播放时间使用的是pts时间，而非dts。这样是否可以考虑到B帧 的dts、pts不相等的问题？
代码逻辑大致如下（暂时未考虑存在B帧的情况，认为视屏的dts与pts相同的前提下）
与之前版本的差异点
1、主线程是等待video播放线程结束再退出的，解决了播放完成无法退出，必须kill -9强杀的问题
2、一共三条线程
2.1、主线程读取视屏流，放到对应的队列中
2.2、一条音频播放线程，更新播放器的时钟
2.3、一条视屏播放线程，判断播放器时钟与当前帧的pts比较，显示图像
关于time_base的知识
暂时可以理解为ffmpeg内的一种时间单位，等同于提倡生活中的其他单位一样：米、千米每小时、千克等等
AVRational time_base;
typedef struct AVRational{
int num; ///< Numerator
int den; ///< Denominator
} AVRational;
从AVRational 的定义中我们可以看到这个时间使用分数来表示的，只有使用相同的时间基，计算出来的时间才有对比的意义。
不管是从设备采集信息保存到文件，还是一个文件播放出图像。都会有这样几个过程
1、mux/demux（分装/解封装）
2、codec/decode（bian/解码）
3、Raw data （YUV/PCM源数据）
每个过程向另一个过程转换，都需要转换这个time_base。
video显示线程内等待audio的代码
video_pts *= av_q2d(is->video_st->time_base);
video_pts = synchronize_video(is, pFrame, video_pts);
while(1)
{
//audio_clock时间再audio线程里播放，更新这个时间
audio_pts = is->audio_clock;
if (video_pts <= audio_pts) break;
int delayTime = (video_pts - audio_pts) * 1000;
delayTime = delayTime > 5 ? 5:delayTime;
SDL_Delay(delayTime);
}
audio线程计算 audio_clock的代码
//基本思路是根据当前音频的声道数，采样位数，采样率，还有本次copy的数据大小，来计算播放玩buffer内数据的时间（这个时间不是很准确）
n = is->audioFrame->channels * is->audio_st->codec->channels;
is->audio_clock += (double) len1 / (double) (n * is->audio_st->codec->sample_rate);
//time = bufsize /（声道数 * 采样位数 * 采样率）
//（声道数 * 采样位数 * 采样率）这一块可以理解为一秒钟可以播放的数据的大小
完整的代码
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavutil/pixfmt.h>
#include <libswscale/swscale.h>
#include <SDL.h>
#include <SDL_audio.h>
#include <SDL_types.h>
#include <SDL_name.h>
#include <SDL_main.h>
#include <SDL_config.h>
#include <SDL2/SDL_thread.h>
#ifdef __cplusplus
};
#endif
#include <stdio.h>
//Refresh
#define SFM_REFRESH_EVENT (SDL_USEREVENT + 1)
//audio play end
#define SFM_AUDIOEND_EVENT (SDL_USEREVENT + 1)
//先按照提供的acc文件播放，后续修改
#define SDL_AUDIO_BUFFER_SIZE 1024
#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio
#define PLAY_REFRESH_TIME 10 //刷新时间间隔
#define MAX_AUDIO_SIZE (25 * 16 * 1024)
#define MAX_VIDEO_SIZE (25 * 256 * 1024)
typedef struct PacketQueue {
AVPacketList *first_pkt, *last_pkt; //首尾指针
int nb_packets; //包个数
int size; //队列大小
SDL_mutex *mutex; //队列互斥锁
SDL_cond *cond; //队列全局变量
} PacketQueue;
typedef struct VideoState {
AVFormatContext *VideoFormatCtx;
AVCodecContext *aCodecCtx; //音频解码器
AVCodecContext *vCodecCtx; //音频解码器
AVFrame *audioFrame;// 解码音频过程中的使用缓存
PacketQueue audioq; //音频队列
unsigned int audio_buf_size;
unsigned int audio_buf_index;
//AVPacket audio_pkt;
uint8_t *audio_pkt_data;
uint8_t *audio_pkt_size;
uint8_t *audio_buf;
// 做两个线程同步使用
double audio_clock; ///音频时钟
double video_clock; ///<pts of last decoded frame / predicted pts of next decoded frame
AVStream *video_st; //视频流
AVStream *audio_st; //音频流
PacketQueue videoq; //视频队列
SDL_Thread *video_tid; //视频线程id
SDL_Thread *refresh_tid; //视频刷新线程id
SDL_AudioDeviceID audioID; //audio模块打开的设备ID
} VideoState;
//SDL播放回调
void audio_callback(void *userdata, Uint8 *stream, int len);
//播放流队列初始化
void packet_queue_init(PacketQueue *q);
//播放流添加入队列
int packet_queue_put(PacketQueue *q, AVPacket *pkt);
//播放流出队列
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block);
//从流中解码音频数据
int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size);
///显示视频帧
void Video_Display_To_Window(
VideoState *is, //video play 状态机
AVPacket *packet, //包
AVFrame *pFrame, //流
AVFrame *pFrameYUV, //YUV流
AVCodecContext *pCodecCtx, //解码上下文
SDL_Texture *bmp, //显示句柄
SDL_Renderer *renderer, //渲染器句柄
struct SwsContext *img_convert_ctx,//转码数据
SDL_Rect rect //显示区域
);
int sfp_refresh_thread(void *opaque); //SDL新线程入口
//调整同步时间
static double synchronize_video(VideoState *is, AVFrame *src_frame, double pts);
//音频处理
int audio_stream_component_open(VideoState *is, int stream_index);
//视频播放线程
int video_play(void *arg);
int thread_exit=0;
// 分配解码过程中的使用缓存
//AVFrame* audioFrame = avcodec_alloc_frame();
AVFrame *audioFrame = NULL;
PacketQueue *audioq = NULL;
VideoState is = {0};
#undef main
int main(int argc, char *argv[])
{
AVFormatContext *pFormatCtx; //视频上下文
AVCodecContext *pCodecCtx, *videoCodeCtx; //解码上下文
int i, audioindex, videoindex;
AVCodec *pCodec, *videoCodec; //解码器
AVPacket *packet, *VideoPacket; //打包的流数据
AVFrame *FrameAudio, *FrameVideo, *FrameYUV;
uint8_t* out_buffer;
int numBytes;
int wait_flag = 0;
SDL_Event event;
char *filename = "./test3.mp4";
//SDL thread
if(1 == argc)
{
printf("%s:%d parameter error \n", __func__, __LINE__);
return -1;
}
audioFrame = av_frame_alloc();
//==================固定的结构================start====================
//1、注册所有的解码器
av_register_all();
//printf("%s -- %d\n", __func__, __LINE__);
//2、分配空间
pFormatCtx = avformat_alloc_context();
//videoCodeCtx = avformat_alloc_context();
//printf("%s -- %d\n", __func__, __LINE__);
if(pFormatCtx)
{
//3、打开文件
if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL) != 0) //error
{
printf("Couldn't open input stream.\n");
return -1;
}
}
//dump 视频信息
av_dump_format(pFormatCtx, 0, argv[1], 0);
//4、检索视频流信息
if(avformat_find_stream_info(pFormatCtx,NULL)<0)
{
printf("Couldn't find stream information.\n");
return -1;
}
//5、查找流位置
audioindex = -1;
videoindex = -1;
for(i = 0; i < pFormatCtx->nb_streams; i ++)
{
printf("cur type :%d\n", pFormatCtx->streams[i]->codec->codec_type);
if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)
{
audioindex = i;
}
if((pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) && (videoindex < 0))
{
videoindex = i;
}
}
if((videoindex < 0) && (audioindex < 0))
{
printf("not fine audio or video stream! \n");
return -1;
}
printf("audioindex:%d, videoindex:%d\n", audioindex, videoindex);
//6、解码上下文
pCodecCtx = pFormatCtx->streams[audioindex]->codec;
videoCodeCtx = pFormatCtx->streams[videoindex]->codec;
//7、、获取视频解码器
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
videoCodec = avcodec_find_decoder(videoCodeCtx->codec_id);
if(pCodec==NULL)
{
printf("Codec not found.\n");
return -1;
}
//8、、打开解码器
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)
{
printf("Could not open audio codec.\n");
return -1;
}
if(avcodec_open2(videoCodeCtx, videoCodec,NULL)<0)
{
printf("Could not open video codec.\n");
return -1;
}
//======================固定的结构===========end====================
//=================SDL=============start===========
if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
printf( "Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}
//video statu init
is.VideoFormatCtx = avformat_alloc_context();
is.VideoFormatCtx = pFormatCtx;
is.audioFrame = av_frame_alloc();
is.aCodecCtx = pCodecCtx;
is.vCodecCtx = videoCodeCtx;
is.audio_buf = (uint8_t *)malloc((AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2);
is.video_tid = SDL_CreateThread(video_play, "video_play", &is);
is.audio_st = pFormatCtx->streams[audioindex];
is.video_st = pFormatCtx->streams[videoindex];
//printf("%s -- %d\n", __func__, __LINE__);
/// 打开SDL播放设备 - 结束
//=================SDL=============end=============
//创建一个队列，并且初始化
audio_stream_component_open(&is, audioindex);
packet = av_packet_alloc();
if(!packet)
{
printf("Could not malloc packet.\n");
return -1;
}
// Debug -- Begin
printf("比特率 %3d\n", pFormatCtx->bit_rate);
printf("解码器名称 %s\n", pCodecCtx->codec->long_name);
printf("time_base %d \n", pCodecCtx->time_base);
printf("声道数 %d \n", pCodecCtx->channels);
printf("sample per second %d \n", pCodecCtx->sample_rate);
// Debug -- End
//主线程。读取流到对应的队列。
while(1)
{
if((is.audioq.size > MAX_AUDIO_SIZE) || (is.videoq.size > MAX_VIDEO_SIZE))
{
SDL_Delay(10); //队列限制以下大小，防止一下读取太多的包，导致内存吃完
continue;
}
if(av_read_frame(pFormatCtx, packet) < 0) //流已经读取完了
{
//Exit Thread
thread_exit=1;
break;
}
if(packet->stream_index == audioindex)
{
packet_queue_put(&is.audioq, packet);
//这里我们将数据存入队列 因此不调用 av_free_packet 释放
}else if(packet->stream_index == videoindex) //display video stream
{
packet_queue_put(&is.videoq, packet);
}else{
// Free the packet that was allocated by av_read_frame
av_free_packet(packet);
}
}
printf("read finished!\n");
wait_flag = 1;
do
{
SDL_WaitEvent(&event);
if(SFM_AUDIOEND_EVENT == event.type)
{
printf("main thread wait audio thread exit!\n");
wait_flag = 0;
}
}while(wait_flag);
//等待ideo play线程退出
SDL_WaitThread(is.video_tid, NULL);
av_free(FrameAudio);
avcodec_close(pCodecCtx);// Close the codec
avformat_close_input(&pFormatCtx);// Close the video file
return 0;
}
void audio_callback(void *userdata, Uint8 *stream, int len)
{
VideoState *is = (VideoState *)userdata;
int len1, audio_data_size;
int n = 0;
if((NULL != is) && (NULL != stream)) //参数检查
{
int audio_buf_size = (AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2;
while (len > 0) {
if (is->audio_buf_index >= is->audio_buf_size) {
audio_data_size = audio_decode_frame(is, is->audio_buf, audio_buf_size);
if (audio_data_size < 0) {
is->audio_buf_size = 1024;
memset(is->audio_buf, 0, is->audio_buf_size);
} else {
is->audio_buf_size = audio_data_size;
}
is->audio_buf_index = 0;
}
len1 = is->audio_buf_size - is->audio_buf_index;
if (len1 > len) {
len1 = len;
}
//音频PTS暂时现这样写，坑了再改
if(is->audio_st->codec)
{
//n = 2 * is->audio_st->codec->channels;
n = is->audioFrame->channels * is->audio_st->codec->channels;
is->audio_clock += (double) len1 / (double) (n * is->audio_st->codec->sample_rate);
}
memcpy(stream, (uint8_t *) is->audio_buf + is->audio_buf_index, len1);
len -= len1;
stream += len1;
is->audio_buf_index += len1;
}
}
}
//初始化队列
void packet_queue_init(PacketQueue *q)
{
memset(q, 0, sizeof(PacketQueue));
q->mutex = SDL_CreateMutex();
q->cond = SDL_CreateCond();
}
//数据进入到队列中
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)
q->first_pkt = pkt1;
else
q->last_pkt->next = pkt1;
q->last_pkt = pkt1;
q->nb_packets++;
q->size += pkt1->pkt.size;
SDL_CondSignal(q->cond);
SDL_UnlockMutex(q->mutex);
return 0;
}
//从队列中取走数据
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
AVPacketList *pkt1;
int ret;
SDL_LockMutex(q->mutex);
for (;;) {
pkt1 = q->first_pkt;
if (pkt1) {
q->first_pkt = pkt1->next;
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->cond, q->mutex);
}
}
SDL_UnlockMutex(q->mutex);
return ret;
}
//解码流数据到
int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size)
{
static AVPacket *pkt;
static uint8_t *audio_pkt_data = NULL;
static int audio_pkt_size = 0;
int len1, data_size;
SDL_Event event;
pkt = av_packet_alloc();
for(;;)
{
if(packet_queue_get(&is->audioq, pkt, 0) < 0)
{
return -1;
}
//printf("%s %d\n", __func__, __LINE__);
is->audio_pkt_data = pkt->data;
is->audio_pkt_size = pkt->size;
if(is->audio_pkt_size <= 0)
{
//向主线程发送音频播放完成的消息
event.type = SFM_AUDIOEND_EVENT;
SDL_PushEvent(&event);
return 0; //没有数据，直接返回
}
while(is->audio_pkt_size > 0)
{
int got_picture;
int ret = avcodec_decode_audio4( is->aCodecCtx, is->audioFrame, &got_picture, pkt);
if( ret < 0 ) {
printf("Error in decoding audio frame.\n");
exit(0);
}
//printf("%s %d\n", __func__, __LINE__);
if( got_picture ) {
int in_samples = is->audioFrame->nb_samples;
short *sample_buffer = (short*)malloc(is->audioFrame->nb_samples * 2 * 2);
memset(sample_buffer, 0, is->audioFrame->nb_samples * 4);
int i=0;
float *inputChannel0 = (float*)(is->audioFrame->extended_data[0]);
//printf("%s %d in_samples:%d \n", __func__, __LINE__, in_samples);
// Mono 单声道
if( is->audioFrame->channels == 1 ) {
for( i=0; i<in_samples; i++ ) {
float sample = *inputChannel0++;
if( sample < -1.0f ) {
sample = -1.0f;
} else if( sample > 1.0f ) {
sample = 1.0f;
}
sample_buffer[i] = (int16_t)(sample * 32767.0f);
}
} else { // Stereo 双声道
float* inputChannel1 = (float*)(is->audioFrame->extended_data[1]);
for( i=0; i<in_samples; i++) {
sample_buffer[i*2] = (int16_t)((*inputChannel0++) * 32767.0f);
sample_buffer[i*2+1] = (int16_t)((*inputChannel1++) * 32767.0f);
}
}
memcpy(audio_buf,sample_buffer,in_samples*4);
free(sample_buffer);
}
is->audio_pkt_size -= ret;
if (is->audioFrame->nb_samples <= 0)
{
continue;
}
data_size = is->audioFrame->nb_samples * 4;
return data_size;
}
if(pkt->data)
av_free_packet(pkt);
}
}
///显示视频帧
void Video_Display_To_Window(
VideoState *is, //video play 状态机
AVPacket *packet, //包
AVFrame *pFrame, //流
AVFrame *pFrameYUV, //YUV流
AVCodecContext *pCodecCtx, //解码上下文
SDL_Texture *bmp, //显示句柄
SDL_Renderer *renderer, //渲染器句柄
struct SwsContext *img_convert_ctx,//转码数据
SDL_Rect rect //显示区域
)
{
int got_picture;
SDL_Rect DisplayRect = {0};
int ret = 0;
double video_pts = 0; //当前视频的pts
double audio_pts = 0; //音频pts
DisplayRect.x = rect.x;
DisplayRect.y = rect.y;
DisplayRect.w = rect.w;
DisplayRect.h = rect.h;
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
if(ret < 0)
{
printf("Decode Error.\n");
return -1;
}
if (packet->dts == AV_NOPTS_VALUE && pFrame->opaque&& *(uint64_t*) pFrame->opaque != AV_NOPTS_VALUE)
{
video_pts = *(uint64_t *) pFrame->opaque;
}
else if (packet->dts != AV_NOPTS_VALUE)
{
video_pts = packet->dts;
}
else
{
video_pts = 0;
}
#if 0
printf("%s %d ！\n", __func__, __LINE__);
printf("num:%d den:%d\n", is->video_st->time_base.num, is->video_st->time_base.den);
printf("num:%d den:%d\n", is->aCodecCtx->time_base.num, is->aCodecCtx->time_base.den);
video_pts *= av_q2d(is->video_st->time_base);
printf("video_pts:%f ！\n", video_pts);
video_pts = synchronize_video(is, pFrame, video_pts);
printf("%s %d ！\n", __func__, __LINE__);
printf("video_pts: %f, audio_pts:%f\n", video_pts, is->audio_clock);
#else
video_pts *= av_q2d(is->video_st->time_base);
video_pts = synchronize_video(is, pFrame, video_pts);
#endif
while(1)
{
//audio_clock时间再audio线程里播放，更新这个时间
audio_pts = is->audio_clock;
if (video_pts <= audio_pts) break;
int delayTime = (video_pts - audio_pts) * 1000;
delayTime = delayTime > 5 ? 5:delayTime;
SDL_Delay(delayTime);
}
if(got_picture)
{
//printf("update texture to SDL widows!\n");
sws_scale(
img_convert_ctx,
(uint8_t const * const *)pFrame->data,
pFrame->linesize,
0,
pCodecCtx->height,
pFrameYUV->data,
pFrameYUV->linesize
);
////iPitch 计算yuv一行数据占的字节数
SDL_UpdateTexture( bmp, &DisplayRect, pFrameYUV->data[0], pFrameYUV->linesize[0] );
//SDL_UpdateYUVTexture(bmp, &rect, pFrameYUV->data[0], pFrameYUV->linesize[0], pFrameYUV->data[1], pFrameYUV->linesize[1], pFrameYUV->data[2], pFrameYUV->linesize[2]);
SDL_RenderClear( renderer );
SDL_RenderCopy( renderer, bmp, &DisplayRect, &DisplayRect );
SDL_RenderPresent( renderer );
}
//av_free_packet(packet);
}
//Thread
int sfp_refresh_thread(void *opaque)
{
SDL_Event event;
VideoState *is = (VideoState *)opaque;
printf("%s %d refresh thread id:%d !\n", __func__, __LINE__, is->refresh_tid);
//while (is->refresh_tid != 0)
//先把消息发过去，播放线程在等消息
do
{
event.type = SFM_REFRESH_EVENT;
SDL_PushEvent(&event);
//Wait x ms
SDL_Delay(PLAY_REFRESH_TIME);
}while(is->refresh_tid != 0);
return 0;
}
//调整同步时间
static double synchronize_video(VideoState *is, AVFrame *src_frame, double pts)
{
double frame_delay;
if (pts != 0) {
is->video_clock = pts;
} else {
pts = is->video_clock;
}
frame_delay = av_q2d(is->video_st->codec->time_base);
frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
is->video_clock += frame_delay;
return pts;
}
//音频处理
int audio_stream_component_open(VideoState *is, int stream_index)
{
AVFormatContext *ic = is->VideoFormatCtx;
AVCodecContext *codecCtx;
AVCodec *codec;
SDL_AudioSpec wanted_spec, spec;
int64_t wanted_channel_layout = 0;
int wanted_nb_channels;
const int next_nb_channels[] = { 0, 0, 1, 6, 2, 6, 4, 6 };
if (stream_index < 0 || stream_index >= ic->nb_streams)
{
return -1;
}
printf("%s %d entry !\n", __func__, __LINE__);
packet_queue_init(&is->audioq); //初始化音频队列
#if 0
wanted_spec.format = AUDIO_S16SYS; // 具体含义请查看“SDL宏定义”部分
wanted_spec.silence = 0; // 0指示静音
wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; // 自定义SDL缓冲区大小
wanted_spec.callback = audio_callback; // 音频解码的关键回调函数
wanted_spec.userdata = is; // 传给上面回调函数的外带数据
do{
is->audioID = SDL_OpenAudioDevice(SDL_GetAudioDeviceName(0,0),0,&wanted_spec, &spec,0);
printf("SDL_OpenAudio (%d channels): %s\n",wanted_spec.channels, SDL_GetError());
wanted_spec.channels = next_nb_channels[FFMIN(7, wanted_spec.channels)];
if (!wanted_spec.channels) //逐个匹配频道
{
printf("No more channel combinations to tyu, audio open failed\n");
// return -1;
break;
}
}while(is->audioID == 0);
SDL_PauseAudioDevice(is->audioID,0);
#endif
#if 1
/// 打开SDL播放设备 - 开始
SDL_LockAudio();
wanted_spec.freq = is->aCodecCtx->sample_rate;
wanted_spec.format = AUDIO_S16SYS;
wanted_spec.channels = is->aCodecCtx->channels;
wanted_spec.silence = 0;
wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
wanted_spec.callback = audio_callback;
wanted_spec.userdata = is;
if(SDL_OpenAudio(&wanted_spec, &spec) < 0)
{
fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
return -1;
}
SDL_UnlockAudio();
SDL_PauseAudio(0); //开始播放
#endif
}
//视频播放线程
int video_play(void *arg)
{
//========SDL==========
//SDL---------------------------
int screen_w=0,screen_h=0;
SDL_Window *screen;
SDL_Renderer* sdlRenderer;
SDL_Texture* sdlTexture;
SDL_Rect sdlRect;
int ret, got_picture;
struct SwsContext *img_convert_ctx;
SDL_Thread *refresh_tid;
SDL_Event event;
AVFrame *FrameVideo, *FrameYUV;
int numBytes;
uint8_t* out_buffer;
AVPacket *packet;
//=========SDL===end===
VideoState *is = (VideoState *) arg;
//初始化队列
packet_queue_init(&is->videoq);
printf("%s init video queue :%p\n", __func__, &is->videoq);
//=============video====================
FrameVideo = av_frame_alloc();
FrameYUV = av_frame_alloc();
printf("%s %d entry !\n", __func__, __LINE__);
///解码后数据转成YUV420P
img_convert_ctx = sws_getContext(is->vCodecCtx->width, is->vCodecCtx->height, is->vCodecCtx->pix_fmt,
is->vCodecCtx->width, is->vCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
numBytes = avpicture_get_size(AV_PIX_FMT_YUV420P, is->vCodecCtx->width,is->vCodecCtx->height);
out_buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
avpicture_fill((AVPicture *) FrameYUV, out_buffer, AV_PIX_FMT_YUV420P,
is->vCodecCtx->width, is->vCodecCtx->height);
//int y_size = is->vCodecCtx->width * is->vCodecCtx->height;
//packet = (AVPacket *) malloc(sizeof(AVPacket)); //分配一个packet
//av_new_packet(packet, y_size); //分配packet的数据
packet = av_packet_alloc();
screen_w = is->vCodecCtx->width;
screen_h = is->vCodecCtx->height;
printf("%s -- %d\n", __func__, __LINE__);
if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
printf( "Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}
//SDL 2.0 Support for multiple windows
//创建窗口
screen = SDL_CreateWindow("Simplest ffmpeg player's Window", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
screen_w, screen_h,
SDL_WINDOW_OPENGL);
if(!screen) {
printf("SDL: could not create window - exiting:%s\n",SDL_GetError());
return -1;
}
//创建一个渲染器
sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
//IYUV: Y + U + V (3 planes)
//YV12: Y + V + U (3 planes)
sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING,is->vCodecCtx->width,is->vCodecCtx->height);
sdlRect.x=0;
sdlRect.y=0;
sdlRect.w=screen_w;
sdlRect.h=screen_h;
//================video===end===========
//refresh_tid = SDL_CreateThread(sfp_refresh_thread, "play thread", NULL); //创建一个线程定时刷新
is->refresh_tid = SDL_CreateThread(sfp_refresh_thread, "play thread", is); //创建一个线程定时刷新
if(0 > is->refresh_tid)
{
printf("video play create thread fail : %s\n", SDL_GetError());
}
while(1)
{
//printf("%s %d loop\n", __func__, __LINE__);
SDL_WaitEvent(&event); //等待消息到来，再刷新
//printf("%s %d\n", __func__, __LINE__);
if(event.type==SFM_REFRESH_EVENT)
{
//第三个参数改成0，会有这样的情况：当队列中刚好为空，还没来得及往队列中存包，导致播放器意外停止
//如果改成1的话，会导致一直阻塞在读ideo pack中：SDL_CondWait(q->cond, q->mutex);
if (packet_queue_get(&is->videoq, packet, 0) <= 0)
{
//printf("%s read pack end !\n", __func__);
is->refresh_tid = 0;
break;//队列里面没有数据了 读取完毕了
}
Video_Display_To_Window(
is, packet,
FrameVideo, FrameYUV,
is->vCodecCtx, sdlTexture,
sdlRenderer, img_convert_ctx,
sdlRect);
}
}
}
