相关概念

avatar: 针对没有摄像头的用户，使用一个默认头像作为视频来显示，显示给其他人看。

conference flags

video-muxing-personal-canvas：只能看到自己视频（看到自己的canvas），看不到彼此。
video-bridge-first-two：适用于mux模式，如果会议室中只有2个人了，他们只能互相看到对方（应该是全屏都是对方的脸）
video-mute-exit-canvas：视频被mute的用户，就没必要显示在画布上了。
video-required-for-canvas：只显示真实的视频，不显示avatar（无摄像头用户，连个头像都不能显示，阔怜！）
minimize-video-encoding：每个通道的编码输出，都使用独立的视频编码器

avatar：相关属性变量

conference profile parameters: 针对某个会议室的无视频用户
video-no-video-avatar: Path to PNG file for member without video to display.

channel variable: 针对从某个拨号方案入会的无视频用户
video_avatar_png：Path to PNG file to use when an avatar image is needed.

基本的数据结构

会议：conference_obj(核心对象)

下面是将conference里面一些基础的属性去掉，剩下的重要对象。

  1. typedef struct conference_obj {
  2.     char *name;
  3.     ...
  4.     switch_event_t *variables;
  5.     conference_video_mode_t conference_video_mode;
  6.     ...
  7.     switch_codec_settings_t video_codec_settings;
  8.     ...
  9.     uint32_t announce_count;
  10.     ...
  11.     conference_flag_t flags[CFLAG_MAX];
  12.     member_flag_t mflags[MFLAG_MAX];
  13.     ...
  14.     conference_member_t *members;
  15.     ...
  16.     conference_file_node_t *fnode;
  17.     conference_file_node_t *async_fnode;
  18.     ...
  19.     switch_call_cause_t cancel_cause;
  20.     conference_cdr_node_t *cdr_nodes;
  21.     conference_cdr_reject_t *cdr_rejected;
  22.     ...
  23.     struct vid_helper vh[2];
  24.     struct vid_helper mh;
  25.     conference_record_t *rec_node_head;
  26.     ...
  27.     mcu_canvas_t *canvases[MAX_CANVASES+1];
  28.     ...
  29.     switch_fps_t video_fps;
  30.     ...
  31.     video_layout_t *new_personal_vlayout;
  32.     ...
  33. } conference_obj_t;

画布：mcu_canvas_t

  1. typedef struct mcu_canvas_s {
  2.     int width;
  3.     int height;
  4.     switch_image_t *img;
  5.     mcu_layer_t layers[MCU_MAX_LAYERS];
  6.     int res_count;
  7.     int role_count;
  8.     int total_layers;
  9.     int layers_used;
  10.     int layout_floor_id;
  11.     int refresh;
  12.     int send_keyframe;
  13.     int play_file;
  14.     int video_count;
  15.     char *video_layout_group;
  16.     switch_rgb_color_t bgcolor;
  17.     switch_rgb_color_t border_color;
  18.     switch_rgb_color_t letterbox_bgcolor;
  19.     switch_mutex_t *mutex;
  20.     switch_mutex_t *write_mutex;
  21.     switch_timer_t timer;
  22.     switch_memory_pool_t *pool;
  23.     video_layout_t *vlayout;
  24.     video_layout_t *new_vlayout;
  25.     int canvas_id;
  26.     struct conference_obj *conference;
  27.     switch_thread_t *video_muxing_thread;
  28.     int video_timer_reset;
  29.     switch_queue_t *video_queue;
  30.     int recording;
  31.     switch_image_t *bgimg;
  32.     switch_image_t *fgimg;
  33.     int playing_video_file;
  34.     int overlay_video_file;
  35.     codec_set_t *write_codecs[MAX_MUX_CODECS];
  36.     int write_codecs_count;
  37.     switch_bool_t disable_auto_clear;
  38. } mcu_canvas_t;

图层：mcu_layer_t

  1. typedef struct mcu_layer_s {
  2.     mcu_layer_geometry_t geometry;
  3.     int member_id;
  4.     int idx;
  5.     int tagged;
  6.     int bugged;
  7.     uint32_t screen_w;
  8.     uint32_t screen_h;
  9.     int x_pos;
  10.     int y_pos;
  11.     int banner_patched;
  12.     int mute_patched;
  13.     int avatar_patched;
  14.     int refresh;
  15.     int clear;
  16.     int is_avatar;
  17.     int crop_x;
  18.     int crop_y;
  19.     int crop_w;
  20.     int crop_h;
  21.     int last_w;
  22.     int last_h;
  23.     uint32_t img_count;
  24.     switch_image_t *img;
  25.     switch_image_t *cur_img;
  26.     switch_image_t *overlay_img;
  27.     switch_image_t *banner_img;
  28.     switch_image_t *logo_img;
  29.     switch_image_t *mute_img;
  30.     switch_img_txt_handle_t *txthandle;
  31.     conference_file_node_t *fnode;
  32.     switch_img_position_t logo_pos;
  33.     switch_img_fit_t logo_fit;
  34.     struct mcu_canvas_s *canvas;
  35.     int need_patch;
  36.     conference_member_t *member;
  37.     switch_frame_t bug_frame;
  38.     switch_frame_geometry_t last_geometry;
  39.     switch_frame_geometry_t auto_geometry;
  40.     switch_frame_geometry_t zoom_geometry;
  41.     switch_frame_geometry_t pan_geometry;
  42.     switch_frame_geometry_t manual_geometry;
  43.     mcu_layer_cam_opts_t cam_opts;
  44.     switch_mutex_t *overlay_mutex;
  45.     switch_core_video_filter_t overlay_filters;
  46.     int manual_border;
  47. } mcu_layer_t;

会议、画布、图层关系

  1. 一个会议室，包含多个画布，最多为MAX_CANVASES+1 = 21
  2. 一个画布，包含多个图层，最多为MCU_MAX_LAYERS = 64

简陋的时序图

放音方法调用时序

Conference主要数据结构 - 图1

conference_video_muxing_thread_run代码主要流程

  1. 首先来一个死循环
    1. while (conference_globals.running && !conference_utils_test_flag(conference, CFLAG_DESTRUCT) && conference_utils_test_flag(conference, CFLAG_VIDEO_MUXING)) {
    2. ...
    3. }
    只要conference模块还在跑，刚申请的会议室还么释放，会议室还是mux模式，就循环到地老天荒。

conference_function：
2456行调用conference_video_launch_muxing_write_thread

conference_video_muxing_write_thread_run：
用于启动视频帧发送线程，不断的从pop视频帧，然后发送：
pop_status = switch_frame_buffer_pop(member->fb, &pop);