上一篇基本实现了音视频的播放同步，简单的按键控制暂停、恢复、退出操作，这一篇就打算实现播放的进度控制主要是实现快进、快退、重新播放等，但是不打算用SDL来实现GUI操作，主要是用按键操作实现、GUI的部分还是放到用QT实现吧，毕竟不是主要研究SDL的GUI的。
如何实现播放进度控制
想实现播放进度控制，就意味着需要随机的访问流媒体文件，那么就需要使用av_seek_frame或者avformat_seek_file函数。
av_seek_frame
- 函数：int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
- AVFormatContext *s：流媒体打开的上下文结构指针
- int stream_index：流媒体索引，视频流或者是音频流，根据其中一个来检索，实现seek操作
- int64_t timestamp：检索时间戳，若指定流媒体索引，则时间单位是流媒体对应的AVStream.time_base，若不指定流媒体索引，则时间单位是AV_TIME_BASE
- int flags：指明seek操作的标志
#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
#define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
#define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
#define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
当flag中有AVSEEK_FLAG_BYTE时，时间戳要改为byte字节计数
当flag中有AVSEEK_FLAG_FRAME时，表示seek到离timestamp最近的关键帧，对于视频流来说就是I帧，音频流未知。
seek操作要点
- seek操作基准：即seek操作当前时间点，因此在进行播放时需要实时记录音视频流的DTS或者PTS
- seek时间单位：进行seek操作时，根据流索引，确定其时间单位time_base，
- seek时间大小：即向前或者向后seek的时间大小，根据此时间大小和当前时间点，可以计算出向前或者向后进行seek操作时的目标时间
- seek操作载体：即是按照音频还是视频进行seek操作，只需要按照其中一个流进行seek即可，不需要分别对音视频流进行seek操作
- seek操作刷新：在进行seek操作之后，正常播放之前需要将编解码的内部缓冲区进行刷新，同时也要将自行控制的缓冲区内缓存的音视频清零
按视频流seek
首先定义视频流控制结构：
typedef struct __VideoCtrlStruct
{
AVFormatContext *pFormatCtx;
AVStream *pStream;
AVCodec *pCodec;
AVCodecContext *pCodecCtx;
SwsContext *pConvertCtx;
AVFrame *pVideoFrame, *pFrameYUV;
unsigned char *pVideoOutBuffer;
int VideoIndex;
int VideoCnt;
int RefreshTime;
int screen_w,screen_h;
SDL_Window *screen;
SDL_Renderer* sdlRenderer;
SDL_Texture* sdlTexture;
SDL_Rect sdlRect;
SDL_Thread *video_tid;
sem_t frame_put;
sem_t video_refresh;
PacketArrayStruct Video;
}VideoCtrlStruct;
根据seek操作的要点，其中seek时间大小我们可以自行定义，这里暂定为3S
- CurVideoDts：记录视频流当前的DTS
- seek的时间单位：VideoCtrl.pStream->time_base就是视频流的时间单位，
- 前进：int64_t DstVideoDts = CurVideoDts + (int64_t) ( 3 / av_q2d(VideoCtrl.pStream->time_base));
- 后退：int64_t DstVideoDts = CurVideoDts - (int64_t) ( 3 / av_q2d(VideoCtrl.pStream->time_base));
- 因为pStream->time_base结构表示一个分数数据，而视频流中的DTS与PTS时间都是以time_base为时间单位，因此需要将seek时间大小转换为以time_base为时间单位的大小
- seek操作：ret = av_seek_frame(pFormatCtx, VideoIndex, DstVideoDts, AVSEEK_FLAG_FRAME);向后seek是需要在flag参数中加上AVSEEK_FLAG_BACKWARD
- 缓冲区刷新：avcodec_flush_buffers(VideoCtrl.pCodecCtx);
- 因为time_base分数结构中，num基本都为1，因此为了减少浮点数乘除法，可以直接乘以time_base的分母，见以下代码实例
按音频流seek
音频流控制结构
typedef struct __AudioCtrlStruct
{
AVFormatContext *pFormatCtx;
AVStream *pStream;
AVCodec *pCodec;
AVCodecContext *pCodecCtx;
SwrContext *pConvertCtx;
Uint8 *audio_chunk;
Sint32 audio_len;
Uint8 *audio_pos;
int AudioIndex;
int AudioCnt;
uint64_t AudioOutChannelLayout;
int out_nb_samples; //nb_samples: AAC-1024 MP3-1152
AVSampleFormat out_sample_fmt;
int out_sample_rate;
int out_channels;
int out_buffer_size;
unsigned char* pAudioOutBuffer;
sem_t frame_put;
sem_t frame_get;
PacketArrayStruct Audio;
}AudioCtrlStruct;
根据seek操作的要点，其中seek时间大小我们可以自行定义，这里暂定为3S
- CurAudioDts：记录视频流当前的DTS
- seek的时间单位：AudioCtrl.pStream->time_base就是视频流的时间单位，
- 前进：int64_t DstAudioDts = CurAudioDts + (int64_t) ( 3 / av_q2d(AudioCtrl.pStream->time_base));
- 后退：int64_t DstAudioDts = CurAudioDts - (int64_t) ( 3 / av_q2d(AudioCtrl.pStream->time_base));
- 因为pStream->time_base结构表示一个分数数据，而视频流中的DTS与PTS时间都是以time_base为时间单位，因此需要将seek时间大小转换为以time_base为时间单位的大小
-
- seek操作：ret = av_seek_frame(pFormatCtx, AudioIndex, DstAudioDts, AVSEEK_FLAG_FRAME);向后seek是需要在flag参数中加上AVSEEK_FLAG_BACKWARD
- 缓冲区刷新：avcodec_flush_buffers(AudioCtrl.pCodecCtx);
代码实现
此代码用左右方向键表示前进与后退，并且在文件播放完毕时，重头开始播放，使用音频流进行seek操作
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define __STDC_CONSTANT_MACROS
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavutil/time.h>
#include <libavutil/imgutils.h>
#include <libavutil/mathematics.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavdevice/avdevice.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>
#include <SDL2/SDL.h>
#include <errno.h>
#include <unistd.h>
#include <assert.h>
#include <pthread.h>
#include <semaphore.h>
#ifdef __cplusplus
};
#endif
#define MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio
#define PACKET_ARRAY_SIZE (60)
typedef struct __PacketStruct
{
AVPacket Packet;
int64_t dts;
int64_t pts;
int state;
}PacketStruct;
typedef struct
{
unsigned int rIndex;
unsigned int wIndex;
PacketStruct PacketArray[PACKET_ARRAY_SIZE];
}PacketArrayStruct;
typedef struct __AudioCtrlStruct
{
AVFormatContext *pFormatCtx;
AVStream *pStream;
AVCodec *pCodec;
AVCodecContext *pCodecCtx;
SwrContext *pConvertCtx;
Uint8 *audio_chunk;
Sint32 audio_len;
Uint8 *audio_pos;
int AudioIndex;
int AudioCnt;
uint64_t AudioOutChannelLayout;
int out_nb_samples; //nb_samples: AAC-1024 MP3-1152
AVSampleFormat out_sample_fmt;
int out_sample_rate;
int out_channels;
int out_buffer_size;
unsigned char* pAudioOutBuffer;
sem_t frame_put;
sem_t frame_get;
PacketArrayStruct Audio;
}AudioCtrlStruct;
typedef struct __VideoCtrlStruct
{
AVFormatContext *pFormatCtx;
AVStream *pStream;
AVCodec *pCodec;
AVCodecContext *pCodecCtx;
SwsContext *pConvertCtx;
AVFrame *pVideoFrame, *pFrameYUV;
unsigned char *pVideoOutBuffer;
int VideoIndex;
int VideoCnt;
int RefreshTime;
int screen_w,screen_h;
SDL_Window *screen;
SDL_Renderer* sdlRenderer;
SDL_Texture* sdlTexture;
SDL_Rect sdlRect;
SDL_Thread *video_tid;
sem_t frame_put;
sem_t video_refresh;
PacketArrayStruct Video;
}VideoCtrlStruct;
//Refresh Event
#define SFM_REFRESH_VIDEO_EVENT (SDL_USEREVENT + 1)
#define SFM_REFRESH_AUDIO_EVENT (SDL_USEREVENT + 2)
#define SFM_BREAK_EVENT (SDL_USEREVENT + 3)
int thread_exit = 0;
int thread_pause = 0;
int audio_pause = 0; //音频播放是否暂停，1表示暂停，0表示在播放
int video_pause = 0; //视频播放是否暂停，1表示暂停，0表示在播放
SDL_Keycode CurKeyCode; //记录按下的是前进还是后退键，即小键盘的左右方向键，右表示前进，左表示后退
int CurKeyProcess; //按键seek操作是否已经被处理，0表示未处理，1表示已经处理
int64_t CurVideoDts; //记录当前播放的视频流Packet的DTS
int64_t CurVideoPts; //记录当前播放的视频流Packet的DTS
int64_t CurAudioDts; //记录当前播放的音频流Packet的DTS
int64_t CurAudioPts; //记录当前播放的音频流Packet的DTS
int64_t DstAudioDts; //进行seek操作时，计算后的目标音频流的DTS
int64_t DstAudioPts; //进行seek操作时，计算后的目标音频流的PTS
int64_t DstVideoDts; //进行seek操作时，计算后的目标视频流的DTS
int64_t DstVideoPts; //进行seek操作时，计算后的目标视频流的DTS
VideoCtrlStruct VideoCtrl;
AudioCtrlStruct AudioCtrl;
//video time_base.num:1, time_base.den:16, avg_frame_rate.num:8, avg_frame_rate.den:1
//audio time_base.num:1, time_base.den:48000, avg_frame_rate.num:0, avg_frame_rate.den:0
int IsPacketArrayFull(PacketArrayStruct* p)
{
int i = 0;
i = p->wIndex % PACKET_ARRAY_SIZE;
if(p->PacketArray[i].state != 0) return 1;
return 0;
}
int IsPacketArrayEmpty(PacketArrayStruct* p)
{
int i = 0;
i = p->rIndex % PACKET_ARRAY_SIZE;
if(p->PacketArray[i].state == 0) return 1;
return 0;
}
int PacketArrayClear(PacketArrayStruct* p)
{
int i = 0;
for(i = 0; i < PACKET_ARRAY_SIZE; i++)
{
if(p->PacketArray[i].state != 0)
{
av_packet_unref(&p->PacketArray[i].Packet);
p->PacketArray[i].state = 0;
}
}
p->rIndex = 0;
p->wIndex = 0;
return 0;
}
int SDL_event_thread(void *opaque)
{
SDL_Event event;
while(1)
{
SDL_WaitEvent(&event);
if(event.type == SDL_KEYDOWN)
{
//Pause
if(event.key.keysym.sym == SDLK_SPACE)
{
thread_pause = !thread_pause;
printf("video got pause event!\n");
}
if(event.key.keysym.sym == SDLK_RIGHT)
{
thread_pause = !thread_pause;
CurKeyProcess = 0;
CurKeyCode = SDLK_RIGHT;
printf("video got right key event!\n");
}
if(event.key.keysym.sym == SDLK_LEFT)
{
thread_pause = !thread_pause;
CurKeyProcess = 0;
CurKeyCode = SDLK_LEFT;
printf("video got left key event!\n");
}
}
else if(event.type == SDL_QUIT)
{
thread_exit = 1;
printf("------------------------------>video got SDL_QUIT event!\n");
break;
}
else if(event.type == SFM_BREAK_EVENT)
{
break;
}
}
printf("---------> SDL_event_thread end !!!! \n");
return 0;
}
int video_refresh_thread(void *opaque)
{
while (1)
{
if(thread_exit) break;
if(thread_pause)
{
SDL_Delay(40);
continue;
}
//SDL_Delay(40);
usleep(VideoCtrl.RefreshTime);
sem_post(&VideoCtrl.video_refresh);
}
printf("---------> video_refresh_thread end !!!! \n");
return 0;
}
static void *thread_audio(void *arg)
{
AVCodecContext *pAudioCodecCtx;
AVFrame *pAudioFrame;
unsigned char *pAudioOutBuffer;
AVPacket *Packet;
int i, ret, GotAudioPicture;
struct SwrContext *AudioConvertCtx;
AudioCtrlStruct* AudioCtrl = (AudioCtrlStruct*)arg;
pAudioCodecCtx = AudioCtrl->pCodecCtx;
pAudioOutBuffer = AudioCtrl->pAudioOutBuffer;
AudioConvertCtx = AudioCtrl->pConvertCtx;
printf("---------> thread_audio start !!!! \n");
pAudioFrame = av_frame_alloc();
while(1)
{
if(thread_exit) break;
if(thread_pause)
{
usleep(10000);
audio_pause = 1;
continue;
}
if(IsPacketArrayEmpty(&AudioCtrl->Audio))
{
SDL_Delay(1);
printf("---------> thread_audio empty !!!! \n");
continue;
}
audio_pause = 0;
i = AudioCtrl->Audio.rIndex;
Packet = &AudioCtrl->Audio.PacketArray[i].Packet;
CurAudioDts = AudioCtrl->Audio.PacketArray[i].dts;
CurAudioPts = AudioCtrl->Audio.PacketArray[i].pts;
if(Packet->stream_index == AudioCtrl->AudioIndex)
{
ret = avcodec_decode_audio4( pAudioCodecCtx, pAudioFrame, &GotAudioPicture, Packet);
if ( ret < 0 )
{
printf("Error in decoding audio frame.\n");
return 0;
}
if ( GotAudioPicture > 0 )
{
swr_convert(AudioConvertCtx,&pAudioOutBuffer, MAX_AUDIO_FRAME_SIZE,
(const uint8_t **)pAudioFrame->data , pAudioFrame->nb_samples);
printf("Auduo index:%5d\t pts:%ld\t packet size:%d, pFrame->nb_samples:%d\n",
AudioCtrl->AudioCnt, Packet->pts, Packet->size, pAudioFrame->nb_samples);
AudioCtrl->AudioCnt++;
}
while(AudioCtrl->audio_len > 0)//Wait until finish
SDL_Delay(1);
//Set audio buffer (PCM data)
AudioCtrl->audio_chunk = (Uint8 *) pAudioOutBuffer;
AudioCtrl->audio_pos = AudioCtrl->audio_chunk;
AudioCtrl->audio_len = AudioCtrl->out_buffer_size;
av_packet_unref(Packet);
AudioCtrl->Audio.PacketArray[i].state = 0;
i++;
if(i >= PACKET_ARRAY_SIZE) i = 0;
AudioCtrl->Audio.rIndex = i;
}
}
printf("---------> thread_audio end !!!! \n");
return 0;
}
static void *thread_video(void *arg)
{
//AVFormatContext *pFormatCtx;
AVCodecContext *pVideoCodecCtx;
//AVCodec *pVideoCodec;
AVFrame *pVideoFrame,*pFrameYUV;
//unsigned char *pVideoOutBuffer;
AVPacket *Packet;
int i, ret, GotPicture;
struct SwsContext *VideoConvertCtx;
VideoCtrlStruct* VideoCtrl = (VideoCtrlStruct*)arg;
pVideoCodecCtx = VideoCtrl->pCodecCtx;
//pVideoOutBuffer = VideoCtrl->pVideoOutBuffer;
VideoConvertCtx = VideoCtrl->pConvertCtx;
pVideoFrame = VideoCtrl->pVideoFrame;
pFrameYUV = VideoCtrl->pFrameYUV;
printf("---------> thread_video start !!!! \n");
while(1)
{
if(thread_exit) break;
if(thread_pause)
{
usleep(10000);
video_pause = 1;
continue;
}
if(IsPacketArrayEmpty(&VideoCtrl->Video))
{
SDL_Delay(1);
continue;
}
video_pause = 0;
i = VideoCtrl->Video.rIndex;
Packet = &VideoCtrl->Video.PacketArray[i].Packet;
CurVideoDts = VideoCtrl->Video.PacketArray[i].dts;
CurVideoPts = VideoCtrl->Video.PacketArray[i].pts;
if(Packet->stream_index == VideoCtrl->VideoIndex)
{
ret = avcodec_decode_video2(pVideoCodecCtx, pVideoFrame, &GotPicture, Packet);
if(ret < 0)
{
printf("Video Decode Error.\n");
return 0;
}
printf("Video index:%5d\t dts:%ld\t, pts:%ld\t packet size:%d, GotVideoPicture:%d\n",
VideoCtrl->VideoCnt, Packet->dts, Packet->pts, Packet->size, GotPicture);
// printf("Video index:%5d\t pFrame->pkt_dts:%ld, pFrame->pkt_pts:%ld, pFrame->pts:%ld, pFrame->pict_type:%d, "
// "pFrame->best_effort_timestamp:%ld, pFrame->pkt_pos:%ld, pVideoFrame->pkt_duration:%ld\n",
// VideoCtrl->VideoCnt, pVideoFrame->pkt_dts, pVideoFrame->pkt_pts, pVideoFrame->pts,
// pVideoFrame->pict_type, pVideoFrame->best_effort_timestamp,
// pVideoFrame->pkt_pos, pVideoFrame->pkt_duration);
VideoCtrl->VideoCnt++;
if(GotPicture)
{
sws_scale(VideoConvertCtx, (const unsigned char* const*)pVideoFrame->data,
pVideoFrame->linesize, 0, pVideoCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);
sem_wait(&VideoCtrl->video_refresh);
//SDL---------------------------
SDL_UpdateTexture( VideoCtrl->sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0] );
SDL_RenderClear( VideoCtrl->sdlRenderer );
//SDL_RenderCopy( sdlRenderer, sdlTexture, &sdlRect, &sdlRect );
SDL_RenderCopy( VideoCtrl->sdlRenderer, VideoCtrl->sdlTexture, NULL, NULL);
SDL_RenderPresent( VideoCtrl->sdlRenderer );
//SDL End-----------------------
}
av_packet_unref(Packet);
VideoCtrl->Video.PacketArray[i].state = 0;
i++;
if(i >= PACKET_ARRAY_SIZE) i = 0;
VideoCtrl->Video.rIndex = i;
}
}
printf("---------> thread_video end !!!! \n");
return 0;
}
/* The audio function callback takes the following parameters:
* stream: A pointer to the audio buffer to be filled
* len: The length (in bytes) of the audio buffer
*/
void fill_audio(void *udata,Uint8 *stream,int len)
{
AudioCtrlStruct* AudioCtrl = (AudioCtrlStruct*)udata;
//SDL 2.0
SDL_memset(stream, 0, len);
if(AudioCtrl->audio_len == 0) return;
len=(len > AudioCtrl->audio_len ? AudioCtrl->audio_len : len); /* Mix as much data as possible */
SDL_MixAudio(stream, AudioCtrl->audio_pos, len, SDL_MIX_MAXVOLUME);
AudioCtrl->audio_pos += len;
AudioCtrl->audio_len -= len;
}
int main(int argc, char* argv[])
{
AVFormatContext *pFormatCtx;
AVCodecContext *pVideoCodecCtx, *pAudioCodecCtx;
AVCodec *pVideoCodec, *pAudioCodec;
AVPacket *Packet;
unsigned char *pVideoOutBuffer, *pAudioOutBuffer;
int ret;
unsigned int i;
pthread_t audio_tid, video_tid;
uint64_t AudioOutChannelLayout;
//nb_samples: AAC-1024 MP3-1152
int out_nb_samples;
AVSampleFormat out_sample_fmt;
int out_sample_rate;
int out_channels;
//Out Buffer Size
int out_buffer_size;
//------------SDL----------------
struct SwsContext *VideoConvertCtx;
struct SwrContext *AudioConvertCtx;
int VideoIndex, VideoCnt;
int AudioIndex, AudioCnt;
memset(&AudioCtrl, 0, sizeof(AudioCtrlStruct));
memset(&VideoCtrl, 0, sizeof(VideoCtrlStruct));
char *filepath = argv[1];
sem_init(&VideoCtrl.video_refresh, 0, 0);
sem_init(&VideoCtrl.frame_put, 0, 0);
sem_init(&AudioCtrl.frame_put, 0, 0);
thread_exit = 0;
thread_pause = 0;
CurKeyProcess = 1;
CurKeyCode = 0;
av_register_all();
avformat_network_init();
pFormatCtx = avformat_alloc_context();
if(avformat_open_input(&pFormatCtx, filepath, NULL, NULL) !=0 )
{
printf("Couldn't open input stream.\n");
return -1;
}
if(avformat_find_stream_info(pFormatCtx,NULL) < 0)
{
printf("Couldn't find stream information.\n");
return -1;
}
VideoIndex = -1;
AudioIndex = -1;
for(i = 0; i < pFormatCtx->nb_streams; i++)
{
if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
{
VideoIndex = i;
//打印输出视频流的信息
printf("video time_base.num:%d, time_base.den:%d, avg_frame_rate.num:%d, avg_frame_rate.den:%d\n",
pFormatCtx->streams[VideoIndex]->time_base.num,
pFormatCtx->streams[VideoIndex]->time_base.den,
pFormatCtx->streams[VideoIndex]->avg_frame_rate.num,
pFormatCtx->streams[VideoIndex]->avg_frame_rate.den);
}
if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO)
{
AudioIndex = i;
//打印输出音频流的信息
//pFormatCtx->streams[AudioIndex]->time_base.den <<= 1;
printf("audio time_base.num:%d, time_base.den:%d, avg_frame_rate.num:%d, avg_frame_rate.den:%d\n",
pFormatCtx->streams[AudioIndex]->time_base.num,
pFormatCtx->streams[AudioIndex]->time_base.den,
pFormatCtx->streams[AudioIndex]->avg_frame_rate.num,
pFormatCtx->streams[AudioIndex]->avg_frame_rate.den);
}
}
if(VideoIndex != -1)
{ //准备视频的解码操作上下文数据结构，
pVideoCodecCtx = pFormatCtx->streams[VideoIndex]->codec;
pVideoCodec = avcodec_find_decoder(pVideoCodecCtx->codec_id);
if(pVideoCodec == NULL)
{
printf("Video Codec not found.\n");
return -1;
}
if(avcodec_open2(pVideoCodecCtx, pVideoCodec,NULL) < 0)
{
printf("Could not open video codec.\n");
return -1;
}
// prepare video
VideoCtrl.pVideoFrame = av_frame_alloc();
VideoCtrl.pFrameYUV = av_frame_alloc();
ret = av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pVideoCodecCtx->width, pVideoCodecCtx->height, 1);
pVideoOutBuffer = (unsigned char *)av_malloc(ret);
av_image_fill_arrays(VideoCtrl.pFrameYUV->data, VideoCtrl.pFrameYUV->linesize, pVideoOutBuffer,
AV_PIX_FMT_YUV420P, pVideoCodecCtx->width, pVideoCodecCtx->height, 1);
VideoConvertCtx = sws_getContext(pVideoCodecCtx->width, pVideoCodecCtx->height, pVideoCodecCtx->pix_fmt,
pVideoCodecCtx->width, pVideoCodecCtx->height,
AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
VideoCtrl.pFormatCtx = pFormatCtx;
VideoCtrl.pStream = pFormatCtx->streams[VideoIndex];
VideoCtrl.pCodec = pVideoCodec;
VideoCtrl.pCodecCtx = pFormatCtx->streams[VideoIndex]->codec;
VideoCtrl.pConvertCtx = VideoConvertCtx;
VideoCtrl.pVideoOutBuffer = pVideoOutBuffer;
VideoCtrl.VideoIndex = VideoIndex;
if(pFormatCtx->streams[VideoIndex]->avg_frame_rate.num == 0 ||
pFormatCtx->streams[VideoIndex]->avg_frame_rate.den == 0)
{
VideoCtrl.RefreshTime = 40000;
}
else
{
VideoCtrl.RefreshTime = 1000000 * pFormatCtx->streams[VideoIndex]->avg_frame_rate.den;
VideoCtrl.RefreshTime /= pFormatCtx->streams[VideoIndex]->avg_frame_rate.num;
}
printf("VideoCtrl.RefreshTime:%d\n", VideoCtrl.RefreshTime);
}
else
{
printf("Didn't find a video stream.\n");
}
if(AudioIndex != -1)
{ //准备音频的解码操作上下文数据结构，
pAudioCodecCtx = pFormatCtx->streams[AudioIndex]->codec;
pAudioCodec = avcodec_find_decoder(pAudioCodecCtx->codec_id);
if(pAudioCodec == NULL)
{
printf("Audio Codec not found.\n");
return -1;
}
if(avcodec_open2(pAudioCodecCtx, pAudioCodec,NULL) < 0)
{
printf("Could not open audio codec.\n");
return -1;
}
// prepare Out Audio Param
AudioOutChannelLayout = AV_CH_LAYOUT_STEREO;
out_nb_samples = pAudioCodecCtx->frame_size * 2; //nb_samples: AAC-1024 MP3-1152
out_sample_fmt = AV_SAMPLE_FMT_S16;
out_sample_rate = pAudioCodecCtx->sample_rate * 2;
// 此处一定使用pAudioCodecCtx->sample_rate这个变量赋值，否则使用不一样的值会造成音频少采样或者过采样，导致音频播放出现杂音
out_channels = av_get_channel_layout_nb_channels(AudioOutChannelLayout);
out_buffer_size = av_samples_get_buffer_size(NULL,out_channels ,out_nb_samples,out_sample_fmt, 1);
//mp3:out_nb_samples:1152, out_channels:2, out_buffer_size:4608, pCodecCtx->channels:2
//aac:out_nb_samples:1024, out_channels:2, out_buffer_size:4096, pCodecCtx->channels:2
printf("out_nb_samples:%d, out_channels:%d, out_buffer_size:%d, pCodecCtx->channels:%d\n",
out_nb_samples, out_channels, out_buffer_size, pAudioCodecCtx->channels);
pAudioOutBuffer = (uint8_t *)av_malloc(MAX_AUDIO_FRAME_SIZE*2);
//FIX:Some Codec's Context Information is missing
int64_t in_channel_layout = av_get_default_channel_layout(pAudioCodecCtx->channels);
//Swr
AudioConvertCtx = swr_alloc();
AudioConvertCtx = swr_alloc_set_opts(AudioConvertCtx, AudioOutChannelLayout,
out_sample_fmt, out_sample_rate,
in_channel_layout, pAudioCodecCtx->sample_fmt ,
pAudioCodecCtx->sample_rate, 0, NULL);
swr_init(AudioConvertCtx);
AudioCtrl.pFormatCtx = pFormatCtx;
AudioCtrl.pStream = pFormatCtx->streams[AudioIndex];
AudioCtrl.pCodec = pAudioCodec;
AudioCtrl.pCodecCtx = pFormatCtx->streams[AudioIndex]->codec;
AudioCtrl.pConvertCtx = AudioConvertCtx;
AudioCtrl.AudioOutChannelLayout = AudioOutChannelLayout;
AudioCtrl.out_nb_samples = out_nb_samples;
AudioCtrl.out_sample_fmt = out_sample_fmt;
AudioCtrl.out_sample_rate = out_sample_rate;
AudioCtrl.out_channels = out_channels;
AudioCtrl.out_buffer_size = out_buffer_size;
AudioCtrl.pAudioOutBuffer = pAudioOutBuffer;
AudioCtrl.AudioIndex = AudioIndex;
}
else
{
printf("Didn't find a audio stream.\n");
}
//Output Info-----------------------------
printf("---------------- File Information ---------------\n");
av_dump_format(pFormatCtx, 0, filepath, 0);
printf("-------------- File Information end -------------\n");
if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
{
printf( "Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}
if(VideoIndex != -1)
{
//SDL 2.0 Support for multiple windows
//SDL_VideoSpec
VideoCtrl.screen_w = pVideoCodecCtx->width;
VideoCtrl.screen_h = pVideoCodecCtx->height;
VideoCtrl.screen = SDL_CreateWindow("Simplest ffmpeg player's Window", SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED, VideoCtrl.screen_w, VideoCtrl.screen_h, SDL_WINDOW_OPENGL);
if(!VideoCtrl.screen)
{
printf("SDL: could not create window - exiting:%s\n",SDL_GetError());
return -1;
}
VideoCtrl.sdlRenderer = SDL_CreateRenderer(VideoCtrl.screen, -1, 0);
//IYUV: Y + U + V (3 planes)
//YV12: Y + V + U (3 planes)
VideoCtrl.sdlTexture = SDL_CreateTexture(VideoCtrl.sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING,
pVideoCodecCtx->width, pVideoCodecCtx->height);
VideoCtrl.sdlRect.x = 0;
VideoCtrl.sdlRect.y = 0;
VideoCtrl.sdlRect.w = VideoCtrl.screen_w;
VideoCtrl.sdlRect.h = VideoCtrl.screen_h;
VideoCtrl.video_tid = SDL_CreateThread(video_refresh_thread, NULL, NULL);
ret = pthread_create(&video_tid, NULL, thread_video, &VideoCtrl);
if (ret)
{
printf("create thr_rvs video thread failed, error = %d \n", ret);
return -1;
}
}
if(AudioIndex != -1)
{
//SDL_AudioSpec
SDL_AudioSpec AudioSpec;
AudioSpec.freq = out_sample_rate;
AudioSpec.format = AUDIO_S16SYS;
AudioSpec.channels = out_channels;
AudioSpec.silence = 0;
AudioSpec.samples = out_nb_samples;
AudioSpec.callback = fill_audio;
AudioSpec.userdata = (void*)&AudioCtrl;
if (SDL_OpenAudio(&AudioSpec, NULL) < 0)
{
printf("can't open audio.\n");
return -1;
}
ret = pthread_create(&audio_tid, NULL, thread_audio, &AudioCtrl);
if (ret)
{
printf("create thr_rvs video thread failed, error = %d \n", ret);
return -1;
}
SDL_PauseAudio(0);
}
SDL_Thread *event_tid;
event_tid = SDL_CreateThread(SDL_event_thread, NULL, NULL);
VideoCnt = 0;
AudioCnt = 0;
Packet = (AVPacket *)av_malloc(sizeof(AVPacket));
av_init_packet(Packet);
while(1)
{
if( thread_pause )
{
if((CurKeyProcess == 0) && video_pause && audio_pause)
{
switch(CurKeyCode)
{
case SDLK_RIGHT:
//DstAudioDts = CurAudioDts + (int64_t) (3 / av_q2d(AudioCtrl.pStream->time_base));
//因为time_base分数结构中，num基本都为1，因此为了减少浮点数乘除法，可以直接乘以time_base的分母
DstAudioDts = CurAudioDts + 3*AudioCtrl.pStream->time_base.den;
DstVideoDts = CurVideoDts + 3*VideoCtrl.pStream->time_base.den;
ret = av_seek_frame(pFormatCtx, AudioIndex, DstAudioDts, AVSEEK_FLAG_FRAME);
//ret = av_seek_frame(pFormatCtx, VideoIndex, DstVideoDts, AVSEEK_FLAG_FRAME);
printf("SDLK_RIGHT av_seek_frame ret = %d, CurAudioDts:%ld, CurVideoDts:%ld, DstVideoDts:%ld, DstAudioDts:%ld\n",
ret, CurAudioDts, CurVideoDts, DstVideoDts, DstAudioDts);
avcodec_flush_buffers(AudioCtrl.pCodecCtx);
avcodec_flush_buffers(VideoCtrl.pCodecCtx);
PacketArrayClear(&VideoCtrl.Video);
PacketArrayClear(&AudioCtrl.Audio);
break;
case SDLK_LEFT:
DstAudioDts = CurAudioDts - 3*AudioCtrl.pStream->time_base.den;
DstVideoDts = CurVideoDts - 3*VideoCtrl.pStream->time_base.den;
if(DstAudioDts < 0) DstAudioDts = 0;
if(DstVideoDts < 0) DstVideoDts = 0;
ret = av_seek_frame(pFormatCtx, AudioIndex, DstAudioDts, AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_FRAME);
//ret = av_seek_frame(pFormatCtx, VideoIndex, DstVideoDts, AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_FRAME);
printf("SDLK_LEFT av_seek_frame ret = %d, CurAudioDts:%ld, CurVideoDts:%ld, DstVideoDts:%ld, DstAudioDts:%ld\n",
ret, CurAudioDts, CurVideoDts, DstVideoDts, DstAudioDts);
avcodec_flush_buffers(AudioCtrl.pCodecCtx);
avcodec_flush_buffers(VideoCtrl.pCodecCtx);
PacketArrayClear(&VideoCtrl.Video);
PacketArrayClear(&AudioCtrl.Audio);
break;
default:
break;
}
CurKeyProcess = 1;
thread_pause = !thread_pause;
}
usleep(10000);
continue;
}
if(av_read_frame(pFormatCtx, Packet) < 0)
{
// thread_exit = 1;
// SDL_Event event;
// event.type = SFM_BREAK_EVENT;
// SDL_PushEvent(&event);
// printf("---------> av_read_frame < 0, thread_exit = 1 !!!\n");
// break;
av_seek_frame(pFormatCtx, AudioIndex, 0, AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_FRAME);
continue;
}
if(Packet->stream_index == VideoIndex)
{
if(VideoCtrl.Video.wIndex >= PACKET_ARRAY_SIZE)
{
VideoCtrl.Video.wIndex = 0;
}
while(IsPacketArrayFull(&VideoCtrl.Video))
{
usleep(5000);
//printf("---------> VideoCtrl.Video.PacketArray FULL !!!\n");
}
i = VideoCtrl.Video.wIndex;
VideoCtrl.Video.PacketArray[i].Packet = *Packet;
VideoCtrl.Video.PacketArray[i].dts = Packet->dts;
VideoCtrl.Video.PacketArray[i].pts = Packet->pts;
VideoCtrl.Video.PacketArray[i].state = 1;
VideoCtrl.Video.wIndex++;
//printf("VideoCtrl packet put,dts:%ld, pts:%ld, VideoCnt:%d\n", Packet->dts, Packet->pts, VideoCnt++);
}
if(Packet->stream_index == AudioIndex)
{
if(AudioCtrl.Audio.wIndex >= PACKET_ARRAY_SIZE)
{
AudioCtrl.Audio.wIndex = 0;
}
while(IsPacketArrayFull(&AudioCtrl.Audio))
{
usleep(5000);
//printf("---------> AudioCtrl.Audio.PacketArray FULL !!!\n");
}
i = AudioCtrl.Audio.wIndex;
AudioCtrl.Audio.PacketArray[i].Packet = *Packet;
AudioCtrl.Audio.PacketArray[i].dts = Packet->dts;
AudioCtrl.Audio.PacketArray[i].pts = Packet->pts;
AudioCtrl.Audio.PacketArray[i].state = 1;
AudioCtrl.Audio.wIndex++;
//printf("AudioCtrl.frame_put, AudioCnt:%d\n", AudioCnt++);
}
if(thread_exit) break;
}
SDL_WaitThread(event_tid, NULL);
SDL_WaitThread(VideoCtrl.video_tid, NULL);
pthread_join(audio_tid, NULL);
pthread_join(video_tid, NULL);
SDL_CloseAudio();//Close SDL
SDL_Quit();
swr_free(&AudioConvertCtx);
sws_freeContext(VideoConvertCtx);
av_free(pVideoOutBuffer);
avcodec_close(pVideoCodecCtx);
av_free(pAudioOutBuffer);
avcodec_close(pAudioCodecCtx);
avformat_close_input(&pFormatCtx);
printf("--------------------------->main exit 8 ！！\n");
}
好了，下一篇就要开始研究怎么用QT与FFmpeg相结合了，估计需要一点时间了。