记录开发中实际涉及的MPlayer知识
启动MPlayer的代码执行流程
1)系统初始化
play_next_file:
......
2)打开播放文件构造`stream`以及调用demuxer去识别文件格式:
2.1)Open & Sync STREAM
......
current_module="open_stream";
mpctx->stream = open_stream(filename, 0, &mpctx->file_format);
.......
if(0 == mpctx->stream->end_pos){
/*如果播放的是不准确的文件则删除当前文件然后跳到`goto_next_file`*/
sprintf(tmp_arr, "%s%s", "rm -rf ", filename);
if(system(tmp_arr) < 0){
mp_msg(MSGT_CPLAYER,MSGL_INFO,"remove illegal music file err!!!\n");
}
goto goto_next_file;
}
2.2)Open DEMUXERS --- DETECT file type
......
current_module="demux_open";
mpctx->demuxer=demux_open(mpctx->stream,mpctx->file_format,audio_id,video_id,dvdsub_id,filename);
......
if(!mpctx->demuxer){
/*如果在demux中未能成功被过滤器识别，则跳到`goto_next_file`*/
goto goto_next_file;
}
......
main:
3)播放的主体部分
......
3.1) //============================ SETUP AUDIO ===============================
......
/*为该音频流寻找最佳的codec*/
reinit_audio_chain();
->init_best_audio_codec();
->init_audio();
->{
// ok, it matches all rules, let's find the driver!
for (i = 0; mpcodecs_ad_drivers[i] != NULL; i++){
if (!strcmp(mpcodecs_ad_drivers[i]->info->short_name, sh_audio->codec->drv)){
break;
}
/*mpcodecs_ad_drivers[]数组里面就是注册的各种codec了*/
mpadec = mpcodecs_ad_drivers[i];
}
3.2) START PLAYING
/*真正开始输出音频数据*/
while(!mpctx->eof){
......
if(!mpctx->sh_audio && mpctx->d_audio->sh) {
mpctx->sh_audio = mpctx->d_audio->sh;
mpctx->sh_audio->ds = mpctx->d_audio;
reinit_audio_chain();
}
//============================ PLAY AUDIO ===============================
if (!fill_audio_out_buffers()){
//mp_msg(MSGT_CPLAYER,MSGL_INFO,"\n at eof!!!!!!:\n");
mp_msg(MSGT_CPLAYER,MSGL_INFO,"ANS_END=at end of !!!!!:\n");
// at eof, all audio at least written to ao
if (!mpctx->sh_video)
mpctx->eof = PT_NEXT_ENTRY;
}
......
if(!mpctx->sh_video) {
// handle audio-only case:
double a_pos=0;
// sh_audio can be NULL due to video stream switching
// TODO: handle this better
if((!quiet || end_at.type == END_AT_TIME) && mpctx->sh_audio)
a_pos = playing_audio_pts(mpctx->sh_audio, mpctx->d_audio, mpctx->audio_out);
if(end_at.type == END_AT_TIME && end_at.pos < a_pos)
mpctx->eof = PT_NEXT_ENTRY;
update_subtitles(NULL, a_pos, mpctx->d_sub, 0);
update_osd_msg();
}
......
//============================ Handle PAUSE ===============================
current_module = "pause";
......
//================= Keyboard events, SEEKing ====================
current_module = "key_events";
......
}
goto_next_file:
4)播放结束，转到下一个文件
......
/*清理为了播放上个文件所用到的各种资源*/
while(mpctx->playtree_iter != NULL) {
filename = play_tree_iter_get_file(mpctx->playtree_iter,mpctx->eof);
if(filename == NULL) {
if(play_tree_iter_step(mpctx->playtree_iter,mpctx->eof,0) != PLAY_TREE_ITER_ENTRY) {
play_tree_iter_free(mpctx->playtree_iter);
mpctx->playtree_iter = NULL;
};
} else
break;
}
......
if(use_gui || mpctx->playtree_iter != NULL || player_idle_mode){
if(!mpctx->playtree_iter) filename = NULL;
mpctx->eof = 0;
goto play_next_file;
}