ijkplayer加速播放

最新在写一个公司的直播类项目，要求视频播放延迟200毫秒以内,采用kcp协议，ijkplayer做接收端的播放器，ijkplayer加速播放的地方做个记录，以免自己忘记

修改ijkplayer/ijkmedia/ijkplayer/ff_ffplay.c里的

static int ffplay_video_thread

这个方法

static int ffplay_video_thread(void *arg)
{
    FFPlayer *ffp = arg;
    VideoState *is = ffp->is;
    AVFrame *frame = av_frame_alloc();
    double pts;
    double duration;
    int ret;
    AVRational tb = is->video_st->time_base;
    AVRational frame_rate = av_guess_frame_rate(is->ic, is->video_st, NULL);
    int64_t dst_pts = -1;
    int64_t last_dst_pts = -1;
    int retry_convert_image = 0;
    int convert_frame_count = 0;

#if CONFIG_AVFILTER
    AVFilterGraph *graph = avfilter_graph_alloc();
    AVFilterContext *filt_out = NULL, *filt_in = NULL;
    int last_w = 0;
    int last_h = 0;
    enum AVPixelFormat last_format = -2;
    int last_serial = -1;
    int last_vfilter_idx = 0;
    if (!graph) {
        av_frame_free(&frame);
        return AVERROR(ENOMEM);
    }

#else
    ffp_notify_msg2(ffp, FFP_MSG_VIDEO_ROTATION_CHANGED, ffp_get_video_rotate_degrees(ffp));
#endif

    if (!frame) {
#if CONFIG_AVFILTER
        avfilter_graph_free(&graph);
#endif
        return AVERROR(ENOMEM);
    }

    for (;;) {
        ret = get_video_frame(ffp, frame);
        if (ret < 0)
            goto the_end;
        if (!ret)
            continue;

        if (ffp->get_frame_mode) {
            if (!ffp->get_img_info || ffp->get_img_info->count <= 0) {
                av_frame_unref(frame);
                continue;
            }

            last_dst_pts = dst_pts;

            if (dst_pts < 0) {
                dst_pts = ffp->get_img_info->start_time;
            } else {
                dst_pts += (ffp->get_img_info->end_time - ffp->get_img_info->start_time) / (ffp->get_img_info->num - 1);
            }

            pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(tb);
            pts = pts * 1000;
            if (pts >= dst_pts) {
                while (retry_convert_image <= MAX_RETRY_CONVERT_IMAGE) {
                    ret = convert_image(ffp, frame, (int64_t)pts, frame->width, frame->height);
                    if (!ret) {
                        convert_frame_count++;
                        break;
                    }
                    retry_convert_image++;
                    av_log(NULL, AV_LOG_ERROR, "convert image error retry_convert_image = %d\n", retry_convert_image);
                }

                retry_convert_image = 0;
                if (ret || ffp->get_img_info->count <= 0) {
                    if (ret) {
                        av_log(NULL, AV_LOG_ERROR, "convert image abort ret = %d\n", ret);
                        ffp_notify_msg3(ffp, FFP_MSG_GET_IMG_STATE, 0, ret);
                    } else {
                        av_log(NULL, AV_LOG_INFO, "convert image complete convert_frame_count = %d\n", convert_frame_count);
                    }
                    goto the_end;
                }
            } else {
                dst_pts = last_dst_pts;
            }
            av_frame_unref(frame);
            continue;
        }

#if CONFIG_AVFILTER
        if (   last_w != frame->width
            || last_h != frame->height
            || last_format != frame->format
            || last_serial != is->viddec.pkt_serial
            || ffp->vf_changed
            || last_vfilter_idx != is->vfilter_idx) {
            SDL_LockMutex(ffp->vf_mutex);
            ffp->vf_changed = 0;
            av_log(NULL, AV_LOG_DEBUG,
                   "Video frame changed from size:%dx%d format:%s serial:%d to size:%dx%d format:%s serial:%d\n",
                   last_w, last_h,
                   (const char *)av_x_if_null(av_get_pix_fmt_name(last_format), "none"), last_serial,
                   frame->width, frame->height,
                   (const char *)av_x_if_null(av_get_pix_fmt_name(frame->format), "none"), is->viddec.pkt_serial);
            avfilter_graph_free(&graph);
            graph = avfilter_graph_alloc();
            if ((ret = configure_video_filters(ffp, graph, is, ffp->vfilters_list ? ffp->vfilters_list[is->vfilter_idx] : NULL, frame)) < 0) {
                // FIXME: post error
                SDL_UnlockMutex(ffp->vf_mutex);
                goto the_end;
            }
            filt_in  = is->in_video_filter;
            filt_out = is->out_video_filter;
            last_w = frame->width;
            last_h = frame->height;
            last_format = frame->format;
            last_serial = is->viddec.pkt_serial;
            last_vfilter_idx = is->vfilter_idx;
            frame_rate = av_buffersink_get_frame_rate(filt_out);
            SDL_UnlockMutex(ffp->vf_mutex);
        }

        ret = av_buffersrc_add_frame(filt_in, frame);
        if (ret < 0)
            goto the_end;

        while (ret >= 0) {
            is->frame_last_returned_time = av_gettime_relative() / 1000000.0;

            ret = av_buffersink_get_frame_flags(filt_out, frame, 0);
            if (ret < 0) {
                if (ret == AVERROR_EOF)
                    is->viddec.finished = is->viddec.pkt_serial;
                ret = 0;
                break;
            }

            is->frame_last_filter_delay = av_gettime_relative() / 1000000.0 - is->frame_last_returned_time;
            if (fabs(is->frame_last_filter_delay) > AV_NOSYNC_THRESHOLD / 10.0)
                is->frame_last_filter_delay = 0;
            tb = av_buffersink_get_time_base(filt_out);
#endif
            //获取缓存的packets,因为我们不需要缓存,这里加速播
            int64_t  video_cache_packets= ffp->stat.video_cache.packets;
            //每秒是30帧,有缓冲的时候,120 四倍的播放速率
            if(video_cache_packets>=2){
                frame_rate.num=120;
            }
            //没有缓存的时候，按正常29帧的速率来播放
            if(video_cache_packets==0){
                frame_rate.num=29;
            }
            
            duration = (frame_rate.num && frame_rate.den ? av_q2d((AVRational){frame_rate.den, frame_rate.num}) : 0);
            //超过5帧,1帧播放0.005秒
            if(video_cache_packets>=5){
                duration=0.005;
            }
            pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(tb);
            ret = queue_picture(ffp, frame, pts, duration, frame->pkt_pos, is->viddec.pkt_serial
                                );
            av_frame_unref(frame);
#if CONFIG_AVFILTER
        }
#endif

        if (ret < 0)
            goto the_end;
    }
 the_end:
#if CONFIG_AVFILTER
    avfilter_graph_free(&graph);
#endif
    av_log(NULL, AV_LOG_INFO, "convert image convert_frame_count = %d\n", convert_frame_count);
    av_frame_free(&frame);
    return 0;
}

在
//获取缓存的packets,因为我们不需要缓存,这里加速播
这里做修改