【ijkplayer】整体结构总结（一）

淡淡的烟草味﹌ 2024-04-08 11:12 46阅读 0赞

## ijkplayer ##

[【ijkplayer】整体结构总结（一）][ijkplayer]

[【ijkplayer】read\_thread 流程梳理（二）][ijkplayer_read_thread]

[【ijkplayer】解码流程梳理（三）][ijkplayer 1]

[【ijkplayer】渲染流程梳理（四）][ijkplayer 2]

--------------------

## 【ijkplayer】整体结构总结（一） ##

Java层—JNI层—C层，作为一个播放器的整体流程，整体结构体如下。  
![在这里插入图片描述][d89e8268281e48dcb71f1589f9653bd7.png]

## 主要结构体 ##

在初始化`native_setUp`的时候，创建了`IjkMediaPlayer`、`FFPlayer`、`IJKFF_Pipeline`，在`prepare`阶段通过`stream_open`创建了`VideoState`，这几个结构体基本贯穿了整个流程，非常重要

### IjkMediaPlayer ###

表示native层的Player，与Java层一对一绑定。作为Java到c的入口封装。

struct IjkMediaPlayer {
        
        volatile int ref_count;
        pthread_mutex_t mutex;
        FFPlayer *ffplayer;
    
        int (*msg_loop)(void*);
        SDL_Thread *msg_thread;
        SDL_Thread _msg_thread;
    
        int mp_state;
        char *data_source;
        void *weak_thiz;
    
        int restart;
        int restart_from_beginning;
        int seek_req;
    };

### FFPlayer ###

具体的播放器，`internal player`，包含`编码`、`输出`等；代码进入到`ff_ffplay.c`后，就都使用的是`FFPlayer`。持有`VideoState`。

typedef struct FFPlayer {
        
        VideoState *is;
    
        /* extra fields */
        SDL_Aout *aout;
        SDL_Vout *vout;
        struct IJKFF_Pipeline *pipeline;
        struct IJKFF_Pipenode *node_vdec;
    
        MessageQueue msg_queue;
    }

### VideoState ###

VideoState，在`stream_open`中被创建，`表示播放过程中的所有状态`。

typedef struct VideoState {
        
        Clock audclk;
        Clock vidclk;
        Clock extclk;
    
        FrameQueue pictq;
        FrameQueue subpq;
        FrameQueue sampq;
    
        Decoder auddec;
        Decoder viddec;
        Decoder subdec;
    
        PacketQueue audioq;
        PacketQueue subtitleq;
        PacketQueue videoq;
    
        int seek_req;
        double frame_timer;
        int abort_request;
        int force_refresh;
        int paused;
    
    }

### IJKFF\_Pipeline ###

ffpipeline`封装了视频解码器和音频解码器/输出`，`实现通过函数指针`。

// ffpipeline_android.c中
    typedef struct IJKFF_Pipeline_Opaque {
        
        FFPlayer      *ffp;
        SDL_mutex     *surface_mutex;
        jobject        jsurface;
        volatile bool  is_surface_need_reconfigure;
    
        bool         (*mediacodec_select_callback)(void *opaque, ijkmp_mediacodecinfo_context *mcc);
        void          *mediacodec_select_callback_opaque;
    
        SDL_Vout      *weak_vout;
    
        float          left_volume;
        float          right_volume;
    } IJKFF_Pipeline_Opaque;
    
    // 在ff_ffpipeline.h
    typedef struct IJKFF_Pipeline_Opaque IJKFF_Pipeline_Opaque;
    typedef struct IJKFF_Pipeline IJKFF_Pipeline;
    struct IJKFF_Pipeline {
        
        SDL_Class             *opaque_class;
        IJKFF_Pipeline_Opaque *opaque;
    
        void            (*func_destroy)             (IJKFF_Pipeline *pipeline);
        IJKFF_Pipenode *(*func_open_video_decoder)  (IJKFF_Pipeline *pipeline, FFPlayer *ffp);
        SDL_Aout       *(*func_open_audio_output)   (IJKFF_Pipeline *pipeline, FFPlayer *ffp);
        IJKFF_Pipenode *(*func_init_video_decoder)  (IJKFF_Pipeline *pipeline, FFPlayer *ffp);
        int           (*func_config_video_decoder)  (IJKFF_Pipeline *pipeline, FFPlayer *ffp);
    };
    
    IJKFF_Pipeline *ffpipeline_alloc(SDL_Class *opaque_class, size_t opaque_size);
    void ffpipeline_free(IJKFF_Pipeline *pipeline);
    void ffpipeline_free_p(IJKFF_Pipeline **pipeline);
    
    // 打开视频解码器
    IJKFF_Pipenode *ffpipeline_open_video_decoder(IJKFF_Pipeline *pipeline, FFPlayer *ffp);
    // 打开音频解码器
    SDL_Aout       *ffpipeline_open_audio_output(IJKFF_Pipeline *pipeline, FFPlayer *ffp);
    
    // 异步初始化IJKFF_Pipenode
    IJKFF_Pipenode* ffpipeline_init_video_decoder(IJKFF_Pipeline *pipeline, FFPlayer *ffp); 
    
    // 异步初始化视频解码器
    int ffpipeline_config_video_decoder(IJKFF_Pipeline *pipeline, FFPlayer *ffp);

## 初始化流程 ##

### native\_setup ###

static void IjkMediaPlayer_native_setup(JNIEnv *env, jobject thiz, jobject weak_this)
    {
        
        MPTRACE("%s\n", __func__);
        IjkMediaPlayer *mp = ijkmp_android_create(message_loop);
        JNI_CHECK_GOTO(mp, env, "java/lang/OutOfMemoryError", "mpjni: native_setup: ijkmp_create() failed", LABEL_RETURN);
    
        jni_set_media_player(env, thiz, mp);
        ijkmp_set_weak_thiz(mp, (*env)->NewGlobalRef(env, weak_this));
        ijkmp_set_inject_opaque(mp, ijkmp_get_weak_thiz(mp));
        ijkmp_set_ijkio_inject_opaque(mp, ijkmp_get_weak_thiz(mp));
        ijkmp_android_set_mediacodec_select_callback(mp, mediacodec_select_callback, ijkmp_get_weak_thiz(mp));
    
    LABEL_RETURN:
        ijkmp_dec_ref_p(&mp);
    }
    //ijkmp_android_create
    IjkMediaPlayer *ijkmp_android_create(int(*msg_loop)(void*))
    {
        
        //初始化 IjkMediaPlayer结构体
        IjkMediaPlayer *mp = ijkmp_create(msg_loop);
        if (!mp)
            goto fail;
        //  创建SDL_Vout
        mp->ffplayer->vout = SDL_VoutAndroid_CreateForAndroidSurface();
        if (!mp->ffplayer->vout)
            goto fail;
        // 创建IJKFF_Pipeline
        mp->ffplayer->pipeline = ffpipeline_create_from_android(mp->ffplayer);
        if (!mp->ffplayer->pipeline)
            goto fail;
        // 互相绑定s
        ffpipeline_set_vout(mp->ffplayer->pipeline, mp->ffplayer->vout);
    
        return mp;
    
    fail:
        ijkmp_dec_ref_p(&mp);
        return NULL;
    }

### IjkMediaPlayer\_setDataSource ###

int ijkmp_set_data_source(IjkMediaPlayer *mp, const char *url)
    {
        
        assert(mp);
        assert(url);
        MPTRACE("ijkmp_set_data_source(url=\"%s\")\n", url);
        pthread_mutex_lock(&mp->mutex);
        int retval = ijkmp_set_data_source_l(mp, url);
        pthread_mutex_unlock(&mp->mutex);
        MPTRACE("ijkmp_set_data_source(url=\"%s\")=%d\n", url, retval);
        return retval;
    }
    static int ijkmp_set_data_source_l(IjkMediaPlayer *mp, const char *url)
    {
        
        assert(mp);
        assert(url);
    
        // MPST_RET_IF_EQ(mp->mp_state, MP_STATE_IDLE);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_INITIALIZED);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_ASYNC_PREPARING);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_PREPARED);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_STARTED);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_PAUSED);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_COMPLETED);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_STOPPED);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_ERROR);
        MPST_RET_IF_EQ(mp->mp_state, MP_STATE_END);
    
        freep((void**)&mp->data_source);
        mp->data_source = strdup(url);
        if (!mp->data_source)
            return EIJK_OUT_OF_MEMORY;
    
        ijkmp_change_state_l(mp, MP_STATE_INITIALIZED);
        return 0;
    }

### IjkMediaPlayer\_prepareAsync ###

调用流程 `IjkMediaPlayer_prepareAsync`\->`ijkmp_prepare_async_l`\->`ffp_prepare_async_l`\->`stream_open`

### stream\_open ###

封装了所有流程中需要的参数

static VideoState *stream_open(FFPlayer *ffp, const char *filename, AVInputFormat *iformat)
    {
        
        assert(!ffp->is);
        VideoState *is;
    
        is = av_mallocz(sizeof(VideoState));
        if (!is)
            return NULL;
        is->filename = av_strdup(filename);
        if (!is->filename)
            goto fail;
        is->iformat = iformat;
        is->ytop    = 0;
        is->xleft   = 0;
    #if defined(__ANDROID__)
        if (ffp->soundtouch_enable) {
        
            is->handle = ijk_soundtouch_create();
        }
    #endif
    
        /* start video display */
        if (frame_queue_init(&is->pictq, &is->videoq, ffp->pictq_size, 1) < 0)
            goto fail;
        if (frame_queue_init(&is->subpq, &is->subtitleq, SUBPICTURE_QUEUE_SIZE, 0) < 0)
            goto fail;
        if (frame_queue_init(&is->sampq, &is->audioq, SAMPLE_QUEUE_SIZE, 1) < 0)
            goto fail;
    
        if (packet_queue_init(&is->videoq) < 0 ||
            packet_queue_init(&is->audioq) < 0 ||
            packet_queue_init(&is->subtitleq) < 0)
            goto fail;
    
        if (!(is->continue_read_thread = SDL_CreateCond())) {
        
            av_log(NULL, AV_LOG_FATAL, "SDL_CreateCond(): %s\n", SDL_GetError());
            goto fail;
        }
    
        if (!(is->video_accurate_seek_cond = SDL_CreateCond())) {
        
            av_log(NULL, AV_LOG_FATAL, "SDL_CreateCond(): %s\n", SDL_GetError());
            ffp->enable_accurate_seek = 0;
        }
    
        if (!(is->audio_accurate_seek_cond = SDL_CreateCond())) {
        
            av_log(NULL, AV_LOG_FATAL, "SDL_CreateCond(): %s\n", SDL_GetError());
            ffp->enable_accurate_seek = 0;
        }
    
        init_clock(&is->vidclk, &is->videoq.serial);
        init_clock(&is->audclk, &is->audioq.serial);
        init_clock(&is->extclk, &is->extclk.serial);
        is->audio_clock_serial = -1;
        if (ffp->startup_volume < 0)
            av_log(NULL, AV_LOG_WARNING, "-volume=%d < 0, setting to 0\n", ffp->startup_volume);
        if (ffp->startup_volume > 100)
            av_log(NULL, AV_LOG_WARNING, "-volume=%d > 100, setting to 100\n", ffp->startup_volume);
        ffp->startup_volume = av_clip(ffp->startup_volume, 0, 100);
        ffp->startup_volume = av_clip(SDL_MIX_MAXVOLUME * ffp->startup_volume / 100, 0, SDL_MIX_MAXVOLUME);
        is->audio_volume = ffp->startup_volume;
        is->muted = 0;
        is->av_sync_type = ffp->av_sync_type;
    
        is->play_mutex = SDL_CreateMutex();
        is->accurate_seek_mutex = SDL_CreateMutex();
        ffp->is = is;
        is->pause_req = !ffp->start_on_prepared;
    
        is->video_refresh_tid = SDL_CreateThreadEx(&is->_video_refresh_tid, video_refresh_thread, ffp, "ff_vout");
        if (!is->video_refresh_tid) {
        
            av_freep(&ffp->is);
            return NULL;
        }
    
        is->initialized_decoder = 0;
        is->read_tid = SDL_CreateThreadEx(&is->_read_tid, read_thread, ffp, "ff_read");
        if (!is->read_tid) {
        
            av_log(NULL, AV_LOG_FATAL, "SDL_CreateThread(): %s\n", SDL_GetError());
            goto fail;
        }
    
        if (ffp->async_init_decoder && !ffp->video_disable && ffp->video_mime_type && strlen(ffp->video_mime_type) > 0
                        && ffp->mediacodec_default_name && strlen(ffp->mediacodec_default_name) > 0) {
        
            if (ffp->mediacodec_all_videos || ffp->mediacodec_avc || ffp->mediacodec_hevc || ffp->mediacodec_mpeg2) {
        
                decoder_init(&is->viddec, NULL, &is->videoq, is->continue_read_thread);
                ffp->node_vdec = ffpipeline_init_video_decoder(ffp->pipeline, ffp);
            }
        }
        is->initialized_decoder = 1;
    
        return is;
    fail:
        is->initialized_decoder = 1;
        is->abort_request = true;
        if (is->video_refresh_tid)
            SDL_WaitThread(is->video_refresh_tid, NULL);
        stream_close(ffp);
        return NULL;
    }

**video\_refresh\_thread，主要负责音视频同步，以及音视频渲染显示流程。**

**read\_thread ，负责打开流，创建音视频解码线程，读取packet等流程**

### message\_loop ###

消息循环队列，IjkMediaPlayer创建的时候赋值，prepare中创建线程，启动loop，实现机制类似android消息队列锁机制的Looper那一套。

[ijkplayer]: https://blog.csdn.net/weixin_43874301/article/details/126481256
[ijkplayer_read_thread]: https://blog.csdn.net/weixin_43874301/article/details/126481568
[ijkplayer 1]: https://blog.csdn.net/weixin_43874301/article/details/126482052
[ijkplayer 2]: https://codingce.blog.csdn.net/article/details/126483630
[d89e8268281e48dcb71f1589f9653bd7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/08/8e106fbd91aa482a93b964bab1e7b96f.png