ngx_rtmp_live_module.c


/*
 * Copyright (C) Roman Arutyunyan
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include "ngx_rtmp_live_module.h"
#include "ngx_rtmp_cmd_module.h"
#include "ngx_rtmp_codec_module.h"


static ngx_rtmp_publish_pt              next_publish;
static ngx_rtmp_play_pt                 next_play;
static ngx_rtmp_close_stream_pt         next_close_stream;
static ngx_rtmp_pause_pt                next_pause;
static ngx_rtmp_stream_begin_pt         next_stream_begin;
static ngx_rtmp_stream_eof_pt           next_stream_eof;


static ngx_int_t ngx_rtmp_live_postconfiguration(ngx_conf_t *cf);
static void * ngx_rtmp_live_create_app_conf(ngx_conf_t *cf);
static char * ngx_rtmp_live_merge_app_conf(ngx_conf_t *cf,
       void *parent, void *child);
static char *ngx_rtmp_live_set_msec_slot(ngx_conf_t *cf, ngx_command_t *cmd,
       void *conf);
static void ngx_rtmp_live_start(ngx_rtmp_session_t *s);
static void ngx_rtmp_live_stop(ngx_rtmp_session_t *s);


static ngx_command_t  ngx_rtmp_live_commands[] = {

    { ngx_string("live"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, live),
      NULL },

    { ngx_string("stream_buckets"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, nbuckets),
      NULL },

    { ngx_string("buffer"), /*   设置缓存时长 */
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, buflen),
      NULL },

    { ngx_string("sync"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_rtmp_live_set_msec_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, sync),
      NULL },

    { ngx_string("interleave"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, interleave),
      NULL },

    { ngx_string("wait_key"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, wait_key),
      NULL },

    { ngx_string("wait_video"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, wait_video),
      NULL },

    { ngx_string("publish_notify"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, publish_notify),
      NULL },

    { ngx_string("play_restart"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, play_restart),
      NULL },

    { ngx_string("idle_streams"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, idle_streams),
      NULL },

    { ngx_string("drop_idle_publisher"),
      NGX_RTMP_MAIN_CONF|NGX_RTMP_SRV_CONF|NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_rtmp_live_set_msec_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_live_app_conf_t, idle_timeout),
      NULL },

      ngx_null_command
};


static ngx_rtmp_module_t  ngx_rtmp_live_module_ctx = {
    NULL,                                   /* preconfiguration */
    ngx_rtmp_live_postconfiguration,        /* postconfiguration */
    NULL,                                   /* create main configuration */
    NULL,                                   /* init main configuration */
    NULL,                                   /* create server configuration */
    NULL,                                   /* merge server configuration */
    ngx_rtmp_live_create_app_conf,          /* create app configuration */
    ngx_rtmp_live_merge_app_conf            /* merge app configuration */
};


ngx_module_t  ngx_rtmp_live_module = {
    NGX_MODULE_V1,
    &ngx_rtmp_live_module_ctx,              /* module context */
    ngx_rtmp_live_commands,                 /* module directives */
    NGX_RTMP_MODULE,                        /* module type */
    NULL,                                   /* init master */
    NULL,                                   /* init module */
    NULL,                                   /* init process */
    NULL,                                   /* init thread */
    NULL,                                   /* exit thread */
    NULL,                                   /* exit process */
    NULL,                                   /* exit master */
    NGX_MODULE_V1_PADDING
};


static void *
ngx_rtmp_live_create_app_conf(ngx_conf_t *cf)
{
    ngx_rtmp_live_app_conf_t      *lacf;

    lacf = ngx_pcalloc(cf->pool, sizeof(ngx_rtmp_live_app_conf_t));
    if (lacf == NULL) {
        return NULL;
    }

    lacf->live = NGX_CONF_UNSET;
    lacf->nbuckets = NGX_CONF_UNSET;
    lacf->buflen = NGX_CONF_UNSET_MSEC;
    lacf->sync = NGX_CONF_UNSET_MSEC;
    lacf->idle_timeout = NGX_CONF_UNSET_MSEC;
    lacf->interleave = NGX_CONF_UNSET;
    lacf->wait_key = NGX_CONF_UNSET;
    lacf->wait_video = NGX_CONF_UNSET;
    lacf->publish_notify = NGX_CONF_UNSET;
    lacf->play_restart = NGX_CONF_UNSET;
    lacf->idle_streams = NGX_CONF_UNSET;

    return lacf;
}


static char *
ngx_rtmp_live_merge_app_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_rtmp_live_app_conf_t *prev = parent;
    ngx_rtmp_live_app_conf_t *conf = child;

    ngx_conf_merge_value(conf->live, prev->live, 0);
    ngx_conf_merge_value(conf->nbuckets, prev->nbuckets, 1024);
    ngx_conf_merge_msec_value(conf->buflen, prev->buflen, 0);
    ngx_conf_merge_msec_value(conf->sync, prev->sync, 300);
    ngx_conf_merge_msec_value(conf->idle_timeout, prev->idle_timeout, 0);
    ngx_conf_merge_value(conf->interleave, prev->interleave, 0);
    ngx_conf_merge_value(conf->wait_key, prev->wait_key, 1);
    ngx_conf_merge_value(conf->wait_video, prev->wait_video, 0);
    ngx_conf_merge_value(conf->publish_notify, prev->publish_notify, 0);
    ngx_conf_merge_value(conf->play_restart, prev->play_restart, 0);
    ngx_conf_merge_value(conf->idle_streams, prev->idle_streams, 1);

    conf->pool = ngx_create_pool(4096, &cf->cycle->new_log);
    if (conf->pool == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->streams = ngx_pcalloc(cf->pool,
            sizeof(ngx_rtmp_live_stream_t *) * conf->nbuckets);

    return NGX_CONF_OK;
}


static char *
ngx_rtmp_live_set_msec_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    char                       *p = conf;
    ngx_str_t                  *value;
    ngx_msec_t                 *msp;

    msp = (ngx_msec_t *) (p + cmd->offset);

    value = cf->args->elts;

    if (value[1].len == sizeof("off") - 1 &&
        ngx_strncasecmp(value[1].data, (u_char *) "off", value[1].len) == 0)
    {
        *msp = 0;
        return NGX_CONF_OK;
    }

    return ngx_conf_set_msec_slot(cf, cmd, conf);
}

/*

根据名称创建或查找直播流 

*/
static ngx_rtmp_live_stream_t **
ngx_rtmp_live_get_stream(ngx_rtmp_session_t *s, u_char *name, int create)
{
    ngx_rtmp_live_app_conf_t   *lacf;
    ngx_rtmp_live_stream_t    **stream;
    size_t                      len;

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);
    if (lacf == NULL) {
        return NULL;
    }

    len = ngx_strlen(name);
    stream = &lacf->streams[ngx_hash_key(name, len) % lacf->nbuckets];

    for (; *stream; stream = &(*stream)->next) {
        if (ngx_strcmp(name, (*stream)->name) == 0) {
            return stream;
        }
    }

    if (!create) {
        return NULL;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
            "live: create stream '%s'", name);

    if (lacf->free_streams) {
        *stream = lacf->free_streams;
        lacf->free_streams = lacf->free_streams->next;
    } else {
        *stream = ngx_palloc(lacf->pool, sizeof(ngx_rtmp_live_stream_t));
    }
    ngx_memzero(*stream, sizeof(ngx_rtmp_live_stream_t));
    ngx_memcpy((*stream)->name, name,
            ngx_min(sizeof((*stream)->name) - 1, len));
    (*stream)->epoch = ngx_current_msec;

    return stream;
}

/* 空闲检查定时器回调处理  */
static void
ngx_rtmp_live_idle(ngx_event_t *pev)
{
    ngx_connection_t           *c;
    ngx_rtmp_session_t         *s;

    c = pev->data;
    s = c->data;

    ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
                  "live: drop idle publisher");

    ngx_rtmp_finalize_session(s);
}

/*  设置流状态  */
static void
ngx_rtmp_live_set_status(ngx_rtmp_session_t *s, ngx_chain_t *control,
                         ngx_chain_t **status, size_t nstatus,
                         unsigned active)
{
    ngx_rtmp_live_app_conf_t   *lacf;
    ngx_rtmp_live_ctx_t        *ctx, *pctx;
    ngx_chain_t               **cl;
    ngx_event_t                *e;
    size_t                      n;

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: set active=%ui", active);

    if (ctx->active == active) {
        ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "live: unchanged active=%ui", active);
        return;
    }

    ctx->active = active;

    if (ctx->publishing) {

        /* publisher */

        if (lacf->idle_timeout) {
            e = &ctx->idle_evt;

            if (active && !ctx->idle_evt.timer_set) {
                e->data = s->connection;
                e->log = s->connection->log;
                e->handler = ngx_rtmp_live_idle;

                ngx_add_timer(e, lacf->idle_timeout);

            } else if (!active && ctx->idle_evt.timer_set) {
            	/* 需要启动流且启动空闲定时器，需要删除该定时器 */
                ngx_del_timer(e);
            }
        }

        ctx->stream->active = active;

        for (pctx = ctx->stream->ctx; pctx; pctx = pctx->next) {
        	/* 通知播放端 */
            if (pctx->publishing == 0) {
                ngx_rtmp_live_set_status(pctx->session, control, status,
                                         nstatus, active);
            }
        }

        return;
    }

    /* subscriber */

    if (control && ngx_rtmp_send_message(s, control, 0) != NGX_OK) {
        ngx_rtmp_finalize_session(s);
        return;
    }

    if (!ctx->silent) {
        cl = status;

        for (n = 0; n < nstatus; ++n, ++cl) {
            if (*cl && ngx_rtmp_send_message(s, *cl, 0) != NGX_OK) {
                ngx_rtmp_finalize_session(s);
                return;
            }
        }
    }

    ctx->cs[0].active = 0;
    ctx->cs[0].dropped = 0;

    ctx->cs[1].active = 0;
    ctx->cs[1].dropped = 0;
}

/* 
启动发布或播放 

*/
static void
ngx_rtmp_live_start(ngx_rtmp_session_t *s)
{
    ngx_rtmp_core_srv_conf_t   *cscf;
    ngx_rtmp_live_app_conf_t   *lacf;
    ngx_chain_t                *control;
    ngx_chain_t                *status[3];
    size_t                      n, nstatus;

    cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);
	/* 控制报文 */
    control = ngx_rtmp_create_stream_begin(s, NGX_RTMP_MSID);

    nstatus = 0; /* status报文个数 */

    if (lacf->play_restart) {
        status[nstatus++] = ngx_rtmp_create_status(s, 
        										  "NetStream.Play.Start",
                                                   "status", 
                                                   "Start live");
        status[nstatus++] = ngx_rtmp_create_sample_access(s);
    }

    if (lacf->publish_notify) {
        status[nstatus++] = ngx_rtmp_create_status(s,
                                                 "NetStream.Play.PublishNotify",
                                                 "status", 
                                                 "Start publishing");
    }

    ngx_rtmp_live_set_status(s, control, status, nstatus, 1);

    if (control) {
        ngx_rtmp_free_shared_chain(cscf, control);
    }

    for (n = 0; n < nstatus; ++n) {
        ngx_rtmp_free_shared_chain(cscf, status[n]);
    }
}

/*
停止直播发布或播放
*/
static void
ngx_rtmp_live_stop(ngx_rtmp_session_t *s)
{
    ngx_rtmp_core_srv_conf_t   *cscf;
    ngx_rtmp_live_app_conf_t   *lacf;
    ngx_chain_t                *control;
    ngx_chain_t                *status[3];
    size_t                      n, nstatus;

    cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);

    control = ngx_rtmp_create_stream_eof(s, NGX_RTMP_MSID);

    nstatus = 0;

    if (lacf->play_restart) {
        status[nstatus++] = ngx_rtmp_create_status(s, "NetStream.Play.Stop",
                                                   "status", "Stop live");
    }

    if (lacf->publish_notify) {
        status[nstatus++] = ngx_rtmp_create_status(s,
                                               "NetStream.Play.UnpublishNotify",
                                               "status", "Stop publishing");
    }

    ngx_rtmp_live_set_status(s, control, status, nstatus, 0);

    if (control) {
        ngx_rtmp_free_shared_chain(cscf, control);
    }

    for (n = 0; n < nstatus; ++n) {
        ngx_rtmp_free_shared_chain(cscf, status[n]);
    }
}


static ngx_int_t
ngx_rtmp_live_stream_begin(ngx_rtmp_session_t *s, ngx_rtmp_stream_begin_t *v)
{
    ngx_rtmp_live_ctx_t    *ctx;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);

    if (ctx == NULL || ctx->stream == NULL || !ctx->publishing) {
        goto next;
    }

    ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: stream_begin");

    ngx_rtmp_live_start(s);

next:
    return next_stream_begin(s, v);
}


static ngx_int_t
ngx_rtmp_live_stream_eof(ngx_rtmp_session_t *s, ngx_rtmp_stream_eof_t *v)
{
    ngx_rtmp_live_ctx_t    *ctx;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);

    if (ctx == NULL || ctx->stream == NULL || !ctx->publishing) {
        goto next;
    }

    ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: stream_eof");

    ngx_rtmp_live_stop(s);

next:
    return next_stream_eof(s, v);
}

/*
rtmp session加入直播流 
*/
static void
ngx_rtmp_live_join(ngx_rtmp_session_t *s, u_char *name, unsigned publisher)
{
    ngx_rtmp_live_ctx_t            *ctx;
    ngx_rtmp_live_stream_t        **stream;
    ngx_rtmp_live_app_conf_t       *lacf;

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);
    if (lacf == NULL) {
        return;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx && ctx->stream) {
        ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "live: already joined");
        return;
    }

    if (ctx == NULL) {
        ctx = ngx_palloc(s->connection->pool, sizeof(ngx_rtmp_live_ctx_t));
        ngx_rtmp_set_ctx(s, ctx, ngx_rtmp_live_module);
    }

    ngx_memzero(ctx, sizeof(*ctx));

    ctx->session = s;

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: join '%s'", name);

	/* 直播流 用name作key  */
    stream = ngx_rtmp_live_get_stream(s, name, publisher || lacf->idle_streams);

    if (stream == NULL ||
        !(publisher || (*stream)->publishing || lacf->idle_streams))
    {
        ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
                      "live: stream not found");

        ngx_rtmp_send_status(s, "NetStream.Play.StreamNotFound", "error",
                             "No such stream");

        ngx_rtmp_finalize_session(s);

        return;
    }

    if (publisher) {
        if ((*stream)->publishing) {
            ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
                          "live: already publishing");

            ngx_rtmp_send_status(s, "NetStream.Publish.BadName", "error",
                                 "Already publishing");

            return;
        }

        (*stream)->publishing = 1;
    }

    ctx->stream = *stream;   /* 加入直播流指针 */
    ctx->publishing = publisher;
    /*  加入直播流 ctx链表  */
    ctx->next = (*stream)->ctx;  
    (*stream)->ctx = ctx;

    if (lacf->buflen) {
        s->out_buffer = 1;
    }

    ctx->cs[0].csid = NGX_RTMP_CSID_VIDEO;
    ctx->cs[1].csid = NGX_RTMP_CSID_AUDIO;
	/* 发布已经开启，开启播放 */
    if (!ctx->publishing && ctx->stream->active) {
        ngx_rtmp_live_start(s);
    }
}

/*
关闭流 
*/
static ngx_int_t
ngx_rtmp_live_close_stream(ngx_rtmp_session_t *s, ngx_rtmp_close_stream_t *v)
{
    ngx_rtmp_session_t             *ss;
    ngx_rtmp_live_ctx_t            *ctx;
    ngx_rtmp_live_ctx_t			   **cctx; 
    ngx_rtmp_live_ctx_t 		   *pctx;
    ngx_rtmp_live_stream_t        **stream;
    ngx_rtmp_live_app_conf_t       *lacf;

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);
    if (lacf == NULL) {
        goto next;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx == NULL) {
        goto next;
    }

    if (ctx->stream == NULL) {
        ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "live: not joined");
        goto next;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: leave '%s'", ctx->stream->name);

    if (ctx->stream->publishing && ctx->publishing) {
        ctx->stream->publishing = 0;
    }

	/* 从直播流中删除当前播放流  */
    for (cctx = &ctx->stream->ctx; *cctx; cctx = &(*cctx)->next) {
        if (*cctx == ctx) {
        	/* 为当前流，删除，指向当前流指向的下一条流  */
            *cctx = ctx->next; 
            break;
        }
    }
	/* 正在发布或者播放，则停止 */
    if (ctx->publishing || ctx->stream->active) {
        ngx_rtmp_live_stop(s);
    }

	/* 如果是发布端关闭，需要关闭对应的播放流 */
    if (ctx->publishing) {
        ngx_rtmp_send_status(s, "NetStream.Unpublish.Success",
                             "status", "Stop publishing");
        if (!lacf->idle_streams) {
            for (pctx = ctx->stream->ctx; pctx; pctx = pctx->next) {
                if (pctx->publishing == 0) {
                    ss = pctx->session;
                    ngx_log_debug0(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                                   "live: no publisher");
                    ngx_rtmp_finalize_session(ss);
                }
            }
        }
    }

	
    if (ctx->stream->ctx) {
    	/*  该rtmp流对应的直播流还有其他rtmp流 */
        ctx->stream = NULL;
        goto next;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: delete empty stream '%s'",
                   ctx->stream->name);
	/*  该rtmp流对应的直播流没有其他rtmp流，回收直播流内存  */
    stream = ngx_rtmp_live_get_stream(s, ctx->stream->name, 0);
    if (stream == NULL) {
        goto next;
    }
   
    *stream = (*stream)->next;  /*  暂时无使用 */ 
	
    ctx->stream->next = lacf->free_streams; /* 将stream 作为头节点加入释放流链链表 */
    lacf->free_streams = ctx->stream; /*  更新释放流链表地址   */
    ctx->stream = NULL; /* 置NULL,不关联直播流 */

    if (!ctx->silent && !ctx->publishing && !lacf->play_restart) {
        ngx_rtmp_send_status(s, "NetStream.Play.Stop", "status", "Stop live");
    }

next:
    return next_close_stream(s, v);
}

/* 
客户端通知服务端停止或启动播放 
*/
static ngx_int_t
ngx_rtmp_live_pause(ngx_rtmp_session_t *s, ngx_rtmp_pause_t *v)
{
    ngx_rtmp_live_ctx_t            *ctx;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);

    if (ctx == NULL || ctx->stream == NULL) {
        goto next;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: pause=%i timestamp=%f",
                   (ngx_int_t) v->pause, v->position);

    if (v->pause) {
        if (ngx_rtmp_send_status(s, "NetStream.Pause.Notify", "status",
                                 "Paused live")
            != NGX_OK)
        {
            return NGX_ERROR;
        }

        ctx->paused = 1; 

        ngx_rtmp_live_stop(s);

    } else {
        if (ngx_rtmp_send_status(s, "NetStream.Unpause.Notify", "status",
                                 "Unpaused live")
            != NGX_OK)
        {
            return NGX_ERROR;
        }

        ctx->paused = 0;

        ngx_rtmp_live_start(s);
    }

next:
    return next_pause(s, v);
}

/*
直播音视频处理 
*/
static ngx_int_t
ngx_rtmp_live_av(ngx_rtmp_session_t *s, ngx_rtmp_header_t *h,
                 ngx_chain_t *in)
{
    ngx_rtmp_live_ctx_t            *ctx, *pctx;
    ngx_rtmp_codec_ctx_t           *codec_ctx;
    ngx_chain_t                    *header, *coheader, *meta,
                                   *apkt, *aapkt, *acopkt, *rpkt;
    ngx_rtmp_core_srv_conf_t       *cscf;
    ngx_rtmp_live_app_conf_t       *lacf;
    ngx_rtmp_session_t             *ss;
    ngx_rtmp_header_t               ch;   /* 当前rtmp header  */
    ngx_rtmp_header_t  				lh;   /*  上一个rtmp header*/
    ngx_rtmp_header_t   			clh;  /* 音频转化视频的rtmp header   */
    ngx_int_t                       rc, mandatory, dummy_audio;
    ngx_uint_t                      prio;
    ngx_uint_t                      peers;
    ngx_uint_t                      meta_version;
    ngx_uint_t                      csidx;
    uint32_t                        delta;
    ngx_rtmp_live_chunk_stream_t   *cs;
#ifdef NGX_DEBUG
    const char                     *type_s;

    type_s = (h->type == NGX_RTMP_MSG_VIDEO ? "video" : "audio");
#endif

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);
    if (lacf == NULL) {
        return NGX_ERROR;
    }

    if (!lacf->live || in == NULL  || in->buf == NULL) {
        return NGX_OK;
    }
    
	/* 从会话中获取live ctx */
    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx == NULL || ctx->stream == NULL) {
        return NGX_OK;
    }

    if (ctx->publishing == 0) {
        ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "live: %s from non-publisher", type_s);
        return NGX_OK;
    }

    if (!ctx->stream->active) {
        ngx_rtmp_live_start(s);
    }

    if (ctx->idle_evt.timer_set) {
        ngx_add_timer(&ctx->idle_evt, lacf->idle_timeout);
    }

    ngx_log_debug2(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: %s packet timestamp=%uD",
                   type_s, h->timestamp);

    s->current_time = h->timestamp;

    peers = 0;
    apkt = NULL;
    aapkt = NULL;
    acopkt = NULL;
    header = NULL;
    coheader = NULL;
    meta = NULL;
    meta_version = 0;
    mandatory = 0;

    prio = (h->type == NGX_RTMP_MSG_VIDEO ?
            ngx_rtmp_get_video_frame_type(in) : 0);

    cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);

    csidx = !(lacf->interleave || h->type == NGX_RTMP_MSG_VIDEO); /* 视频 csidx为0  音频csidx为0  */

    cs  = &ctx->cs[csidx];

    ngx_memzero(&ch, sizeof(ch));

    ch.timestamp = h->timestamp; /* 从接收报文中获取时间戳 */
    ch.msid = NGX_RTMP_MSID;
    ch.csid = cs->csid;
    ch.type = h->type;  /* 从接收报文中获取类型  */

    lh = ch;

    if (cs->active) {
        lh.timestamp = cs->timestamp;  /* 从流中获取时戳  */
    }

    clh = lh;
    clh.type = (h->type == NGX_RTMP_MSG_AUDIO ? NGX_RTMP_MSG_VIDEO :
                                                NGX_RTMP_MSG_AUDIO); /* 如果是音频与视频相互转换，类型一定是视频  */

    cs->active = 1;
    cs->timestamp = ch.timestamp; /* 更新时戳 */

    delta = ch.timestamp - lh.timestamp;
/*
    if (delta >> 31) {
        ngx_log_debug2(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "live: clipping non-monotonical timestamp %uD->%uD",
                       lh.timestamp, ch.timestamp);

        delta = 0;

        ch.timestamp = lh.timestamp;
    }
*/
    rpkt = ngx_rtmp_append_shared_bufs(cscf, NULL, in);

    ngx_rtmp_prepare_message(s, &ch, &lh, rpkt);

    codec_ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_codec_module);
	/* 转码处理 */
    if (codec_ctx) {

        if (h->type == NGX_RTMP_MSG_AUDIO) {
            header = codec_ctx->aac_header;

            if (lacf->interleave) {
                coheader = codec_ctx->avc_header;
            }

            if (codec_ctx->audio_codec_id == NGX_RTMP_AUDIO_AAC &&
                ngx_rtmp_is_codec_header(in))
            {
                prio = 0;
                mandatory = 1;
            }

        } else {
            header = codec_ctx->avc_header;

            if (lacf->interleave) {
                coheader = codec_ctx->aac_header;
            }

            if (codec_ctx->video_codec_id == NGX_RTMP_VIDEO_H264 &&
                ngx_rtmp_is_codec_header(in))
            {
                prio = 0;
                mandatory = 1;
            }
        }

        if (codec_ctx->meta) {
            meta = codec_ctx->meta;
            meta_version = codec_ctx->meta_version;
        }
    }

    /* broadcast to all subscribers */

    for (pctx = ctx->stream->ctx; pctx; pctx = pctx->next) {
        if (pctx == ctx || pctx->paused) {
        	/* 发布rtmp流本身或者该播放流已中止 */
            continue;
        }

        ss = pctx->session;
        cs = &pctx->cs[csidx];

        /* send metadata */
		/* 发送元数据 */
        if (meta && meta_version != pctx->meta_version) {
            ngx_log_debug0(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                           "live: meta");

            if (ngx_rtmp_send_message(ss, meta, 0) == NGX_OK) {
                pctx->meta_version = meta_version;
            }
        }

        /* sync stream */

        if (cs->active && (lacf->sync && cs->dropped > lacf->sync)) {
            ngx_log_debug2(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                           "live: sync %s dropped=%uD", type_s, cs->dropped);

            cs->active = 0;
            cs->dropped = 0;
        }

        /* absolute packet */

        if (!cs->active) { /*  流没有启动 */

            if (mandatory) {
                ngx_log_debug0(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                               "live: skipping header");
                continue;
            }
			/* 等待视频  */
            if (lacf->wait_video && h->type == NGX_RTMP_MSG_AUDIO &&
                !pctx->cs[0].active)
            {
                ngx_log_debug0(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                               "live: waiting for video");
                continue;
            }
			/* 等待关键帧   */
            if (lacf->wait_key && prio != NGX_RTMP_VIDEO_KEY_FRAME &&
               (lacf->interleave || h->type == NGX_RTMP_MSG_VIDEO))
            {
                ngx_log_debug0(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                               "live: skip non-key");
                continue;
            }

            dummy_audio = 0;
            /* 
            生成dummy audio 
			*/
            if (lacf->wait_video && h->type == NGX_RTMP_MSG_VIDEO &&
                !pctx->cs[1].active)
            {
                dummy_audio = 1;
                if (aapkt == NULL) {
                    aapkt = ngx_rtmp_alloc_shared_buf(cscf); /* aapk如果申请失败，需要作一下失败处理，避免访问空指针  */
                    if(NULL != aapkt){
                   	 ngx_rtmp_prepare_message(s, &clh, NULL, aapkt);
                    }
                }
            }
			/* 转码  */
            if (header || coheader) {

                /* send absolute codec header */

                ngx_log_debug2(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                               "live: abs %s header timestamp=%uD",
                               type_s, lh.timestamp);

                if (header) {
                    if (apkt == NULL) {
                        apkt = ngx_rtmp_append_shared_bufs(cscf, NULL, header);
                        ngx_rtmp_prepare_message(s, &lh, NULL, apkt);
                    }

                    rc = ngx_rtmp_send_message(ss, apkt, 0);
                    if (rc != NGX_OK) {
                        continue;
                    }
                }

                if (coheader) {
                    if (acopkt == NULL) {
                        acopkt = ngx_rtmp_append_shared_bufs(cscf, NULL, coheader);
                        ngx_rtmp_prepare_message(s, &clh, NULL, acopkt);
                    }

                    rc = ngx_rtmp_send_message(ss, acopkt, 0);
                    if (rc != NGX_OK) {
                        continue;
                    }

                } else if (dummy_audio) {
                    ngx_rtmp_send_message(ss, aapkt, 0);
                }

                cs->timestamp = lh.timestamp;
                cs->active = 1;
                ss->current_time = cs->timestamp;

            } else {

                /* send absolute packet */

                ngx_log_debug2(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                               "live: abs %s packet timestamp=%uD",
                               type_s, ch.timestamp);

                if (apkt == NULL) {
                    apkt = ngx_rtmp_append_shared_bufs(cscf, NULL, in);
                    ngx_rtmp_prepare_message(s, &ch, NULL, apkt);
                }

                rc = ngx_rtmp_send_message(ss, apkt, prio);
                if (rc != NGX_OK) {
                    continue;
                }

                cs->timestamp = ch.timestamp;
                cs->active = 1;
                ss->current_time = cs->timestamp;

                ++peers;

                if (dummy_audio) {
                    ngx_rtmp_send_message(ss, aapkt, 0);
                }

                continue;
            }
        }

        /* send relative packet */

        ngx_log_debug2(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                       "live: rel %s packet delta=%uD",
                       type_s, delta);

        if (ngx_rtmp_send_message(ss, rpkt, prio) != NGX_OK) {
            ++pctx->ndropped; 

            cs->dropped += delta;

            if (mandatory) {
                ngx_log_debug0(NGX_LOG_DEBUG_RTMP, ss->connection->log, 0,
                               "live: mandatory packet failed");
                ngx_rtmp_finalize_session(ss);
            }

            continue;
        }

        cs->timestamp += delta;
        ++peers; 
        ss->current_time = cs->timestamp;
    }

    if (rpkt) {
        ngx_rtmp_free_shared_chain(cscf, rpkt);
    }

    if (apkt) {
        ngx_rtmp_free_shared_chain(cscf, apkt);
    }

    if (aapkt) {
        ngx_rtmp_free_shared_chain(cscf, aapkt);
    }

    if (acopkt) {
        ngx_rtmp_free_shared_chain(cscf, acopkt);
    }
    
	/* 更新直播流带宽信息 */
    ngx_rtmp_update_bandwidth(&ctx->stream->bw_in, h->mlen);
    ngx_rtmp_update_bandwidth(&ctx->stream->bw_out, h->mlen * peers);

    ngx_rtmp_update_bandwidth(h->type == NGX_RTMP_MSG_AUDIO ?
                              &ctx->stream->bw_in_audio :
                              &ctx->stream->bw_in_video,
                              h->mlen);

    return NGX_OK;
}


static ngx_int_t
ngx_rtmp_live_publish(ngx_rtmp_session_t *s, ngx_rtmp_publish_t *v)
{
    ngx_rtmp_live_app_conf_t       *lacf;
    ngx_rtmp_live_ctx_t            *ctx;

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);

    if (lacf == NULL || !lacf->live) {
        goto next;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: publish: name='%s' type='%s'",
                   v->name, v->type);

    /* join stream as publisher */

    ngx_rtmp_live_join(s, v->name, 1);

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx == NULL || !ctx->publishing) {
        goto next;
    }

    ctx->silent = v->silent;

    if (!ctx->silent) {
        ngx_rtmp_send_status(s, "NetStream.Publish.Start",
                             "status", "Start publishing");
    }

next:
    return next_publish(s, v);
}


static ngx_int_t
ngx_rtmp_live_play(ngx_rtmp_session_t *s, ngx_rtmp_play_t *v)
{
    ngx_rtmp_live_app_conf_t       *lacf;
    ngx_rtmp_live_ctx_t            *ctx;

    lacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_live_module);

    if (lacf == NULL || !lacf->live) {
        goto next;
    }

    ngx_log_debug4(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                   "live: play: name='%s' start=%uD duration=%uD reset=%d",
                   v->name, (uint32_t) v->start,
                   (uint32_t) v->duration, (uint32_t) v->reset);

    /* join stream as subscriber */

    ngx_rtmp_live_join(s, v->name, 0);

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx == NULL) {
        goto next;
    }

    ctx->silent = v->silent;

    if (!ctx->silent && !lacf->play_restart) {
        ngx_rtmp_send_status(s, "NetStream.Play.Start",
                             "status", "Start live");
        ngx_rtmp_send_sample_access(s);
    }

next:
    return next_play(s, v);
}


static ngx_int_t
ngx_rtmp_live_postconfiguration(ngx_conf_t *cf)
{
    ngx_rtmp_core_main_conf_t          *cmcf;
    ngx_rtmp_handler_pt                *h;

    cmcf = ngx_rtmp_conf_get_module_main_conf(cf, ngx_rtmp_core_module);

    /* register raw event handlers */
	/*  注册音视频直播处理回调 */
    h = ngx_array_push(&cmcf->events[NGX_RTMP_MSG_AUDIO]);
    *h = ngx_rtmp_live_av; 

    h = ngx_array_push(&cmcf->events[NGX_RTMP_MSG_VIDEO]);
    *h = ngx_rtmp_live_av;

    /* chain handlers */

    next_publish = ngx_rtmp_publish;
    ngx_rtmp_publish = ngx_rtmp_live_publish;

    next_play = ngx_rtmp_play;
    ngx_rtmp_play = ngx_rtmp_live_play;

    next_close_stream = ngx_rtmp_close_stream;
    ngx_rtmp_close_stream = ngx_rtmp_live_close_stream;

    next_pause = ngx_rtmp_pause;
    ngx_rtmp_pause = ngx_rtmp_live_pause;

    next_stream_begin = ngx_rtmp_stream_begin;
    ngx_rtmp_stream_begin = ngx_rtmp_live_stream_begin;

    next_stream_eof = ngx_rtmp_stream_eof;
    ngx_rtmp_stream_eof = ngx_rtmp_live_stream_eof;

    return NGX_OK;
}