myvtm/Other/libmediaplayer/video.cpp

#include "video.h"
#include "packet.h"
#include "frame.h"
#include "player.h"

static int queue_picture(player_stat_t *is, AVFrame *src_frame, double pts, double duration, int64_t pos)
{
    frame_t *vp = NULL;

	if (!(vp = frame_queue_peek_writable(&is->video_frm_queue, !is->bread_finished))) {
		return -1;
	}

    vp->sar = src_frame->sample_aspect_ratio;
    vp->uploaded = 0;

    vp->width = src_frame->width;
    vp->height = src_frame->height;
    vp->format = src_frame->format;

    vp->pts = pts;
    vp->duration = duration;
    vp->pos = pos;
    //vp->serial = serial;

    //set_default_window_size(vp->width, vp->height, vp->sar);

    // 将AVFrame拷入队列相应位置
    av_frame_move_ref(vp->frame, src_frame);
    // 更新队列计数及写索引
    frame_queue_push(&is->video_frm_queue);

    return 0;
}


// 从packet_queue中取一个packet，解码生成frame
static int video_decode_frame(AVCodecContext *p_codec_ctx, packet_queue_t *p_pkt_queue, AVFrame *frame, CMediaHostApi* hostapi)
{
    int ret;
    
    while (0 == p_pkt_queue->abort_flag)
    {
		AVPacket pkt = {0};
		av_init_packet(&pkt);
        while (0 == p_pkt_queue->abort_flag)
        {
            // 3. 从解码器接收frame
            // 3.1 一个视频packet含一个视频frame
            //     解码器缓存一定数量的packet后，才有解码后的frame输出
            //     frame输出顺序是按pts的顺序，如IBBPBBP
            //     frame->pkt_pos变量是此frame对应的packet在视频文件中的偏移地址，值同pkt.pos
			
            ret = avcodec_receive_frame(p_codec_ctx, frame);
            if (ret < 0)
            {
                if (ret == AVERROR_EOF)
                {
					hostapi->Debug(MEDIA_LOG_DEBUG, "video avcodec_receive_frame(): the decoder has been fully flushed.");
					avcodec_flush_buffers(p_codec_ctx);
                    return 0;
                }
                else if (ret == AVERROR(EAGAIN))
                {
					//hostapi->Debug(MEDIA_LOG_DEBUG,"video avcodec_receive_frame(): output is not available in this state - " "user must try to send new input");
                    break;
                }
                else
                {
					hostapi->Debug(MEDIA_LOG_DEBUG, "video avcodec_receive_frame(): other errors.");
					continue;
                }
            }
            else
            {
                frame->pts = frame->best_effort_timestamp;
                //frame->pts = frame->pkt_dts;
                return 1;   // 成功解码得到一个视频帧，则返回
            }
        }

        // 1. 取出一个packet。使用pkt对应的serial赋值给d->pkt_serial
        if (packet_queue_get(p_pkt_queue, &pkt, true) < 0){
            return -1;
        }

        if (pkt.data == NULL){
            // 复位解码器内部状态/刷新内部缓冲区。
            avcodec_flush_buffers(p_codec_ctx);
        }
        else{
            // 2. 将packet发送给解码器
            //    发送packet的顺序是按dts递增的顺序，如IPBBPBB
            //    pkt.pos变量可以标识当前packet在视频文件中的地址偏移
			int isend_ret = -1;
			isend_ret = avcodec_send_packet(p_codec_ctx, &pkt);
			
			if (0 != isend_ret){
				if (AVERROR(EAGAIN) == isend_ret) {
					hostapi->Debug(MEDIA_LOG_DEBUG, "receive_frame and send_packet both returned EAGAIN, which is an API violation.");
				}
				else if (AVERROR_EOF == isend_ret) {
					hostapi->Debug(MEDIA_LOG_DEBUG, "the decoder has been flushed, and no new packets can be sent to it");
				}
				else if (AVERROR(EINVAL) == isend_ret) {
					hostapi->Debug(MEDIA_LOG_DEBUG, "codec not opened, it is an encoder, or requires flush");
				}
				else if (AVERROR(ENOMEM) == isend_ret) {
					hostapi->Debug(MEDIA_LOG_DEBUG, "failed to add packet to internal queue, or similar");
				}
				else {
					hostapi->Debug(MEDIA_LOG_DEBUG, "legitimate decoding errors and avcodec_send_packet result is %d.", isend_ret);
				}
			}
            av_packet_unref(&pkt);
        }
    }
}

// 将视频包解码得到视频帧，然后写入picture队列
static int video_decode_thread(void *arg)
{
    player_stat_t *is = (player_stat_t *)arg;
    AVFrame *p_frame = av_frame_alloc();
    double pts = 0.0;
    double duration = 0.0;
    int ret=0;
    int got_picture = 0;

    
    if (p_frame == NULL){
		is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "av_frame_alloc() for p_frame failed.");
		return AVERROR(ENOMEM);
    }

    while (false == is->bvideo_finished)
    {
		AVRational tb = is->p_video_stream[is->index]->time_base;
		AVRational frame_rate = av_guess_frame_rate(is->p_fmt_ctx[is->index], is->p_video_stream[is->index], NULL);

        got_picture = video_decode_frame(is->p_vcodec_ctx[is->index], &is->video_pkt_queue, p_frame, is->rvc_hostapi);
        if (got_picture < 0){
			is->bvideo_finished = true;
			is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "video_decode_frame < 0, goto end and set video_finished flag to true.");
            goto exit;
        }

		AVRational tbdata{ frame_rate.den, frame_rate.num };
		duration = (frame_rate.num && frame_rate.den ? av_q2d(tbdata) : 0);   // 当前帧播放时长
        //duration = (frame_rate.num && frame_rate.den ? av_q2d((AVRational){frame_rate.den, frame_rate.num}) : 0);   // 当前帧播放时长
        pts = (p_frame->pts == AV_NOPTS_VALUE) ? NAN : p_frame->pts * av_q2d(tb);   // 当前帧显示时间戳
        ret = queue_picture(is, p_frame, pts, duration, p_frame->pkt_pos);   // 将当前帧压入frame_queue
        av_frame_unref(p_frame);

        if (ret < 0){
			is->bvideo_finished = true;
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "queue_picture return -1, goto end and set video_finished flag to true.");
            goto exit;
        }
		//av_usleep(RVC_DEFAULT_SLEEP_TIME);
    }

exit:
    av_frame_free(&p_frame);
	is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "video decode thread exit, thread id is %u, and video_finished flag is %s.", SDL_ThreadID(), is->bvideo_finished ? "true" : "false");

    return 0;
}

// 根据视频时钟与同步时钟(如音频时钟)的差值，校正delay值，使视频时钟追赶或等待同步时钟
// 输入参数delay是上一帧播放时长，即上一帧播放后应延时多长时间后再播放当前帧，通过调节此值来调节当前帧播放快慢
// 返回值delay是将输入参数delay经校正后得到的值
static double compute_target_delay(double delay, player_stat_t *is)
{
    double sync_threshold, diff = 0;

    /* update delay to follow master synchronisation source */

    /* if video is slave, we try to correct big delays by
       duplicating or deleting a frame */
    // 视频时钟与同步时钟(如音频时钟)的差异，时钟值是上一帧pts值(实为：上一帧pts + 上一帧至今流逝的时间差)
    diff = get_clock(&is->video_clk) - get_clock(&is->audio_clk);
    // delay是上一帧播放时长：当前帧(待播放的帧)播放时间与上一帧播放时间差理论值
    // diff是视频时钟与同步时钟的差值

    /* skip or repeat frame. We take into account the
       delay to compute the threshold. I still don't know
       if it is the best guess */
    // 若delay < AV_SYNC_THRESHOLD_MIN，则同步域值为AV_SYNC_THRESHOLD_MIN
    // 若delay > AV_SYNC_THRESHOLD_MAX，则同步域值为AV_SYNC_THRESHOLD_MAX
    // 若AV_SYNC_THRESHOLD_MIN < delay < AV_SYNC_THRESHOLD_MAX，则同步域值为delay
    sync_threshold = FFMAX(AV_SYNC_THRESHOLD_MIN, FFMIN(AV_SYNC_THRESHOLD_MAX, delay));
    if (!isnan(diff))
    {
        if (diff <= -sync_threshold)        // 视频时钟落后于同步时钟，且超过同步域值
            delay = FFMAX(0, delay + diff); // 当前帧播放时刻落后于同步时钟(delay+diff<0)则delay=0(视频追赶，立即播放)，否则delay=delay+diff
        else if (diff >= sync_threshold && delay > AV_SYNC_FRAMEDUP_THRESHOLD)  // 视频时钟超前于同步时钟，且超过同步域值，但上一帧播放时长超长
            delay = delay + diff;           // 仅仅校正为delay=delay+diff，主要是AV_SYNC_FRAMEDUP_THRESHOLD参数的作用
        else if (diff >= sync_threshold)    // 视频时钟超前于同步时钟，且超过同步域值
            delay = 2 * delay;              // 视频播放要放慢脚步，delay扩大至2倍
    }

	//is->rvc_hostapi->Debug("video: delay=%0.3f A-V=%f", delay, -diff);
    return delay;
}

static double vp_duration(player_stat_t *is, frame_t *vp, frame_t *nextvp) {
    if (vp->serial == nextvp->serial)
    {
        double duration = nextvp->pts - vp->pts;
        if (isnan(duration) || duration <= 0)
            return vp->duration;
        else
            return duration;
    } else {
        return 0.0;
    }
}

static void update_video_pts(player_stat_t *is, double pts, int64_t pos, int serial) {
    /* update current video pts */
    set_clock(&is->video_clk, pts, serial);            // 更新vidclock
    //-sync_clock_to_slave(&is->extclk, &is->vidclk);  // 将extclock同步到vidclock
}

static void video_display(player_stat_t *is)
{
    frame_t *vp = NULL;

    vp = frame_queue_peek_last(&is->video_frm_queue);

    // 图像转换：p_frm_raw->data ==> p_frm_yuv->data
    // 将源图像中一片连续的区域经过处理后更新到目标图像对应区域，处理的图像区域必须逐行连续
    // plane: 如YUV有Y、U、V三个plane，RGB有R、G、B三个plane
    // slice: 图像中一片连续的行，必须是连续的，顺序由顶部到底部或由底部到顶部
    // stride/pitch: 一行图像所占的字节数，Stride=BytesPerPixel*Width+Padding，注意对齐
    // AVFrame.*data[]: 每个数组元素指向对应plane
    // AVFrame.linesize[]: 每个数组元素表示对应plane中一行图像所占的字节数
    sws_scale(is->img_convert_ctx[is->index],                      // sws context
              (const uint8_t *const *)vp->frame->data,// src slice
              vp->frame->linesize,                    // src stride
              0,                                      // src slice y
              is->p_vcodec_ctx[is->index]->height,               // src slice height
              is->p_frm_yuv[is->index]->data,                    // dst planes
              is->p_frm_yuv[is->index]->linesize                 // dst strides
             );
    
    // 使用新的YUV像素数据更新SDL_Rect
    SDL_UpdateYUVTexture(is->sdl_video.texture,         // sdl texture
                         &is->sdl_video.rect,           // sdl rect
                         is->p_frm_yuv[is->index]->data[0],        // y plane
                         is->p_frm_yuv[is->index]->linesize[0],    // y pitch
                         is->p_frm_yuv[is->index]->data[1],        // u plane
                         is->p_frm_yuv[is->index]->linesize[1],    // u pitch
                         is->p_frm_yuv[is->index]->data[2],        // v plane
                         is->p_frm_yuv[is->index]->linesize[2]     // v pitch
                        );
    
    // 使用特定颜色清空当前渲染目标
    SDL_RenderClear(is->sdl_video.renderer);
    // 使用部分图像数据(texture)更新当前渲染目标
    SDL_RenderCopy(is->sdl_video.renderer,              // sdl renderer
                   is->sdl_video.texture,               // sdl texture
                   NULL,                                // src rect, if NULL copy texture
                   &is->sdl_video.rect                  // dst rect
                  );
    
    // 执行渲染，更新屏幕显示
    SDL_RenderPresent(is->sdl_video.renderer);
}

/* called to display each frame */
static void video_refresh(void *opaque, double *remaining_time)
{
    player_stat_t *is = (player_stat_t *)opaque;
    double time;
    static bool first_frame = true;

retry:
    if (frame_queue_nb_remaining(&is->video_frm_queue) == 0)  // 所有帧已显示
    {    
        // nothing to do, no picture to display in the queue
        return;
    }

    double last_duration, duration, delay;
    frame_t *vp, *lastvp;
    /* dequeue the picture */
    lastvp = frame_queue_peek_last(&is->video_frm_queue);     // 上一帧：上次已显示的帧
    vp = frame_queue_peek(&is->video_frm_queue);              // 当前帧：当前待显示的帧
    // lastvp和vp不是同一播放序列(一个seek会开始一个新播放序列)，将frame_timer更新为当前时间
    if (first_frame)
    {
        is->frame_timer = av_gettime_relative() / 1000000.0;
        first_frame = false;
    }
    // 暂停处理：不停播放上一帧图像
    if (is->paused)
        goto display;

    /* compute nominal last_duration */
    last_duration = vp_duration(is, lastvp, vp);        // 上一帧播放时长：vp->pts - lastvp->pts
    delay = compute_target_delay(last_duration, is);    // 根据视频时钟和同步时钟的差值，计算delay值

    time= av_gettime_relative()/1000000.0;
    // 当前帧播放时刻(is->frame_timer+delay)大于当前时刻(time)，表示播放时刻未到
    if (time < is->frame_timer + delay) {
        // 播放时刻未到，则更新刷新时间remaining_time为当前时刻到下一播放时刻的时间差
        *remaining_time = FFMIN(is->frame_timer + delay - time, *remaining_time);
        // 播放时刻未到，则不播放，直接返回
        return;
    }
    // 更新frame_timer值
    is->frame_timer += delay;
    // 校正frame_timer值：若frame_timer落后于当前系统时间太久(超过最大同步域值)，则更新为当前系统时间
    if (delay > 0 && time - is->frame_timer > AV_SYNC_THRESHOLD_MAX)
    {
        is->frame_timer = time;
    }

    SDL_LockMutex(is->video_frm_queue.frame_mutex);
    if (!isnan(vp->pts))
    {
        update_video_pts(is, vp->pts, vp->pos, vp->serial); // 更新视频时钟：时间戳、时钟时间
    }
    SDL_UnlockMutex(is->video_frm_queue.frame_mutex);

    // 是否要丢弃未能及时播放的视频帧
    if (frame_queue_nb_remaining(&is->video_frm_queue) > 1)  // 队列中未显示帧数>1(只有一帧则不考虑丢帧)
    {         
        frame_t *nextvp = frame_queue_peek_next(&is->video_frm_queue);  // 下一帧：下一待显示的帧
        duration = vp_duration(is, vp, nextvp);             // 当前帧vp播放时长 = nextvp->pts - vp->pts
        // 当前帧vp未能及时播放，即下一帧播放时刻(is->frame_timer+duration)小于当前系统时刻(time)
        if (time > is->frame_timer + duration)
        {
            frame_queue_next(&is->video_frm_queue);   // 删除上一帧已显示帧，即删除lastvp，读指针加1(从lastvp更新到vp)
            goto retry;
        }
    }

    // 删除当前读指针元素，读指针+1。若未丢帧，读指针从lastvp更新到vp；若有丢帧，读指针从vp更新到nextvp
    frame_queue_next(&is->video_frm_queue);
display:
    video_display(is);                      // 取出当前帧vp(若有丢帧是nextvp)进行播放
}

static int video_playing_thread(void *arg)
{
    player_stat_t *is = (player_stat_t *)arg;
    double remaining_time = 0.0;

    while (false == is->bvideo_finished){
        if (remaining_time > 0.0){
            av_usleep((unsigned)(remaining_time * 1000000.0));
        }
        remaining_time = REFRESH_RATE;
        // 立即显示当前帧，或延时remaining_time后再显示
        video_refresh(is, &remaining_time);
		//remaining_time += 0.020;
    }

	is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "video playing thread exit, thread id is %u, and video_finished flag is %s.", SDL_ThreadID(), is->bvideo_finished ? "true" : "false");
    return 0;
}

static Uint32 get_video_playing_wind_flag(eWindType_t eType)
{
	Uint32 uFlag = SDL_WINDOW_OPENGL|SDL_WINDOW_BORDERLESS|SDL_WINDOW_ALWAYS_ON_TOP|SDL_WINDOW_POPUP_MENU;

	return uFlag;
}

static int open_video_playing(void* arg)
{
	player_stat_t* is = (player_stat_t*)arg;
	int ret;
	int buf_size;
	uint8_t* buffer = NULL;
	SDL_Surface* IconSurface = NULL;

	for (size_t index = 0; index < is->uFilesCount; index++) {
		is->p_frm_yuv[index] = av_frame_alloc();
		if (is->p_frm_yuv[index] == NULL) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "av_frame_alloc() for p_frm_raw failed");
			return -1;
		}

		int iplay_video_width = is->p_vcodec_ctx[index]->width;
		int iplay_video_height = is->p_vcodec_ctx[index]->height;
		if (eFullScreen_Type == is->eWindType) {
			iplay_video_width = is->iDisplayWidth;
			iplay_video_height = is->iDisplayHeight;
		}

		// 为AVFrame.*data[]手工分配缓冲区，用于存储sws_scale()中目的帧视频数据
		buf_size = av_image_get_buffer_size(AV_PIX_FMT_YUV420P,
			iplay_video_width,
			iplay_video_height,
			1
		);
		// buffer将作为p_frm_yuv的视频数据缓冲区
		buffer = (uint8_t*)av_malloc(buf_size);
		if (buffer == NULL) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "av_malloc() for buffer failed!");
			return -1;
		}
		is->p_video_buffer[index] = buffer;
		// 使用给定参数设定p_frm_yuv->data和p_frm_yuv->linesize
		ret = av_image_fill_arrays(is->p_frm_yuv[index]->data,     // dst data[]
			is->p_frm_yuv[index]->linesize, // dst linesize[]
			is->p_video_buffer[index],                  // src buffer
			AV_PIX_FMT_YUV420P,      // pixel format
			iplay_video_width,		 // width
			iplay_video_height,		 // height
			1                        // align
		);

		if (ret < 0) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "av_image_fill_arrays() failed %d", ret);
			return -1;;
		}

		// A2. 初始化SWS context，用于后续图像转换
		//     此处第6个参数使用的是FFmpeg中的像素格式，对比参考注释B3
		//     FFmpeg中的像素格式AV_PIX_FMT_YUV420P对应SDL中的像素格式SDL_PIXELFORMAT_IYUV
		//     如果解码后得到图像的不被SDL支持，不进行图像转换的话，SDL是无法正常显示图像的
		//     如果解码后得到图像的能被SDL支持，则不必进行图像转换
		//     这里为了编码简便，统一转换为SDL支持的格式AV_PIX_FMT_YUV420P==>SDL_PIXELFORMAT_IYUV
		is->img_convert_ctx[index] = sws_getContext(is->p_vcodec_ctx[index]->width,   // src width
			is->p_vcodec_ctx[index]->height,  // src height
			is->p_vcodec_ctx[index]->pix_fmt, // src format
			iplay_video_width,   // dst width
			iplay_video_height,  // dst height
			AV_PIX_FMT_YUV420P,        // dst format
			SWS_BICUBIC,               // flags
			NULL,                      // src filter
			NULL,                      // dst filter
			NULL                       // param
		);

		if (is->img_convert_ctx[index] == NULL) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "sws_getContext() failed");
			return -1;
		}
		else {
			is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "%s:%d is->img_convert_ctx[%d] = 0x%08x", __FUNCTION__, __LINE__, index, is->img_convert_ctx[index]);
		}

		
		// SDL_Rect赋值
		is->sdl_video.rect.x = 0;
		is->sdl_video.rect.y = 0;
		is->sdl_video.rect.w = iplay_video_width;
		is->sdl_video.rect.h = iplay_video_height;

		Uint32 uWindFlag = get_video_playing_wind_flag(is->eWindType);

		is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "%s:%d %d %d %d %d", __FUNCTION__, __LINE__, is->iDisplayCx,
		is->iDisplayCy,
		is->sdl_video.rect.w,
		is->sdl_video.rect.h);

		// 1. 创建SDL窗口，SDL 2.0支持多窗口
		//    SDL_Window即运行程序后弹出的视频窗口，同SDL 1.x中的SDL_Surface
		is->sdl_video.window = SDL_CreateWindow("rvc media player",
			is->iDisplayCx,
			is->iDisplayCy,
			is->sdl_video.rect.w,
			is->sdl_video.rect.h,
			uWindFlag
		);

		if (is->sdl_video.window == NULL) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "SDL_CreateWindow() failed: %s.", SDL_GetError());
			return -1;
		}

		if (eFullScreen_Type == is->eWindType) {
			SDL_SetWindowFullscreen(is->sdl_video.window, SDL_WINDOW_FULLSCREEN_DESKTOP);
		}

		int cx = 0, cy = 0;
		SDL_GetWindowPosition(is->sdl_video.window, &cx, &cy);
		is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "window flag is 0x%08x, cx = %d, cy = %d.", SDL_GetWindowFlags(is->sdl_video.window), cx, cy);

		if (NULL != is->piconpath) {
			IconSurface = SDL_LoadBMP(is->piconpath);
			if (NULL == IconSurface) {
				is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "SDL_LoadBMP(%s) failed: %s", is->piconpath, SDL_GetError());
			}
			else {
				SDL_SetWindowIcon(is->sdl_video.window, IconSurface);
				SDL_FreeSurface(IconSurface);
			}
		}

		// 2. 创建SDL_Renderer
		//    SDL_Renderer：渲染器
		is->sdl_video.renderer = SDL_CreateRenderer(is->sdl_video.window, -1, 0);
		if (is->sdl_video.renderer == NULL)
		{
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "SDL_CreateRenderer() failed: %s", SDL_GetError());
			return -1;
		}

		// 3. 创建SDL_Texture
		//    一个SDL_Texture对应一帧YUV数据，同SDL 1.x中的SDL_Overlay
		is->sdl_video.texture = SDL_CreateTexture(is->sdl_video.renderer,
			SDL_PIXELFORMAT_IYUV,
			SDL_TEXTUREACCESS_STREAMING,
			is->sdl_video.rect.w,
			is->sdl_video.rect.h
		);

		if (is->sdl_video.texture == NULL)
		{
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "SDL_CreateTexture() failed: %s", SDL_GetError());
			return -1;
		}

		is->video_playing_tid = SDL_CreateThread(video_playing_thread, "video playing thread", is);
		if (NULL == is->video_playing_tid) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "SDL_Create video playing thread failed: %s.", SDL_GetError());
			return -1;
		}
		else {
			is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "create %s success, and thread id is %u.", SDL_GetThreadName(is->video_playing_tid), SDL_GetThreadID(is->video_playing_tid));
		}
	}

    return 0;
}

static int open_video_stream(player_stat_t *is)
{
    AVCodecParameters* p_codec_par = NULL;
    AVCodec* p_codec = NULL;
    AVCodecContext* p_codec_ctx = NULL;
	int ret = -1;

	for (size_t index = 0; index < is->uFilesCount; index++){
		AVStream* p_stream = is->p_video_stream[index];

		// 1. 为视频流构建解码器AVCodecContext
		// 1.1 获取解码器参数AVCodecParameters
		p_codec_par = p_stream->codecpar;

		// 1.2 获取解码器
		p_codec = avcodec_find_decoder(p_codec_par->codec_id);
		if (p_codec == NULL) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "Cann't find codec!");
			return ret;
		}

		// 1.3 构建解码器AVCodecContext
		// 1.3.1 p_codec_ctx初始化：分配结构体，使用p_codec初始化相应成员为默认值
		p_codec_ctx = avcodec_alloc_context3(p_codec);
		if (p_codec_ctx == NULL) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "avcodec_alloc_context3() failed");
			return ret;
		}
		// 1.3.2 p_codec_ctx初始化：p_codec_par ==> p_codec_ctx，初始化相应成员
		ret = avcodec_parameters_to_context(p_codec_ctx, p_codec_par);
		if (ret < 0) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "avcodec_parameters_to_context() failed");
			return ret;
		}
		// 1.3.3 p_codec_ctx初始化：使用p_codec初始化p_codec_ctx，初始化完成
		ret = avcodec_open2(p_codec_ctx, p_codec, NULL);
		if (ret < 0) {
			is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "avcodec_open2() failed %d", ret);
			return ret;
		}
		is->p_vcodec_ctx[index] = p_codec_ctx;
	}

    // 2. 创建视频解码线程
	is->video_decode_tid = SDL_CreateThread(video_decode_thread, "video decode thread", is);
	if (NULL == is->video_decode_tid) {
		is->rvc_hostapi->Debug(MEDIA_LOG_ERROR, "SDL_Create video decode thread failed: %s.", SDL_GetError());
		return -1;
	}
	else {
		is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "create %s success, and thread id is %u.", SDL_GetThreadName(is->video_decode_tid), SDL_GetThreadID(is->video_decode_tid));
	}

    return 0;
}

int open_video(player_stat_t *is)
{
	is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "enter open_video()");
    open_video_stream(is);
    open_video_playing(is);
	is->rvc_hostapi->Debug(MEDIA_LOG_DEBUG, "exit open_video()");

    return 0;
}