ngx_rtmp_gop_cache_module.c

/*
 * Copyright (C) Gnolizuh
 * Copyright (C) Winshining
 * Copyright (C) HeyJupiter
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include "ngx_http_flv_live_module.h"
#include "ngx_rtmp_gop_cache_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_gop_frame_t *ngx_rtmp_gop_cache_alloc_frame(
    ngx_rtmp_session_t *s);
static ngx_rtmp_gop_frame_t *ngx_rtmp_gop_cache_free_frame(
    ngx_rtmp_session_t *s, ngx_rtmp_gop_frame_t *frame);
static ngx_int_t ngx_rtmp_gop_cache_link_frame(ngx_rtmp_session_t *s,
    ngx_rtmp_gop_frame_t *frame);
static ngx_int_t ngx_rtmp_gop_cache_alloc_cache(ngx_rtmp_session_t *s);
static ngx_rtmp_gop_cache_t *ngx_rtmp_gop_cache_free_cache(
    ngx_rtmp_session_t *s, ngx_rtmp_gop_cache_t *cache);
static void ngx_rtmp_gop_cache_cleanup(ngx_rtmp_session_t *s);
static void ngx_rtmp_gop_cache_update(ngx_rtmp_session_t *s);
static void ngx_rtmp_gop_cache_frame(ngx_rtmp_session_t *s, ngx_uint_t prio,
    ngx_rtmp_header_t *ch, ngx_chain_t *frame);
static void ngx_rtmp_gop_cache_send(ngx_rtmp_session_t *s);
static ngx_int_t ngx_rtmp_gop_cache_av(ngx_rtmp_session_t *s,
    ngx_rtmp_header_t *h, ngx_chain_t *in);
static ngx_int_t ngx_rtmp_gop_cache_publish(ngx_rtmp_session_t *s,
    ngx_rtmp_publish_t *v);
static ngx_int_t ngx_rtmp_gop_cache_play(ngx_rtmp_session_t *s,
    ngx_rtmp_play_t *v);
static ngx_int_t ngx_rtmp_gop_cache_close_stream(ngx_rtmp_session_t *s,
    ngx_rtmp_close_stream_t *v);


static ngx_int_t ngx_rtmp_gop_cache_postconfiguration(ngx_conf_t *cf);
static void *ngx_rtmp_gop_cache_create_app_conf(ngx_conf_t *cf);
static char *ngx_rtmp_gop_cache_merge_app_conf(ngx_conf_t *cf,
    void *parent, void *child);


extern ngx_rtmp_live_proc_handler_t  *ngx_rtmp_live_proc_handlers
                                      [NGX_RTMP_PROTOCOL_HTTP + 1];
extern ngx_module_t                   ngx_http_flv_live_module;


static ngx_command_t ngx_rtmp_gop_cache_commands[] = {
    { ngx_string("gop_cache"),
      NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_gop_cache_app_conf_t, gop_cache),
      NULL },

    { ngx_string("gop_max_frame_count"),
      NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_gop_cache_app_conf_t, gop_max_frame_count),
      NULL },

    { ngx_string("gop_max_video_count"),
      NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_gop_cache_app_conf_t, gop_max_video_count),
      NULL },

    { ngx_string("gop_max_audio_count"),
      NGX_RTMP_APP_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_RTMP_APP_CONF_OFFSET,
      offsetof(ngx_rtmp_gop_cache_app_conf_t, gop_max_audio_count),
      NULL },

    ngx_null_command
};


static ngx_rtmp_module_t ngx_rtmp_gop_cache_module_ctx = {
    NULL,
    ngx_rtmp_gop_cache_postconfiguration, /* postconfiguration */
    NULL,
    NULL,
    NULL,
    NULL,
    ngx_rtmp_gop_cache_create_app_conf,   /* create application configuration */
    ngx_rtmp_gop_cache_merge_app_conf     /* merge application configuration */
};


ngx_module_t ngx_rtmp_gop_cache_module = {
    NGX_MODULE_V1,
    &ngx_rtmp_gop_cache_module_ctx,
    ngx_rtmp_gop_cache_commands,
    NGX_RTMP_MODULE,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NGX_MODULE_V1_PADDING
};


static void *
ngx_rtmp_gop_cache_create_app_conf(ngx_conf_t *cf)
{
    ngx_rtmp_gop_cache_app_conf_t *gacf;

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

    gacf->gop_cache = NGX_CONF_UNSET;
    gacf->gop_cache_count = NGX_CONF_UNSET_SIZE;
    gacf->gop_max_frame_count = NGX_CONF_UNSET_SIZE;
    gacf->gop_max_audio_count = NGX_CONF_UNSET_SIZE;
    gacf->gop_max_video_count = NGX_CONF_UNSET_SIZE;

    return (void *) gacf;
}


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

    ngx_conf_merge_value(conf->gop_cache, prev->gop_cache, 0);
    ngx_conf_merge_size_value(conf->gop_cache_count, prev->gop_cache_count, 2);
    ngx_conf_merge_size_value(conf->gop_max_frame_count,
            prev->gop_max_frame_count, 4096);
    ngx_conf_merge_size_value(conf->gop_max_audio_count,
            prev->gop_max_audio_count, 2048);
    ngx_conf_merge_size_value(conf->gop_max_video_count,
            prev->gop_max_video_count, 2048);

    return NGX_CONF_OK;
}


static ngx_rtmp_gop_frame_t *
ngx_rtmp_gop_cache_alloc_frame(ngx_rtmp_session_t *s)
{
    ngx_rtmp_gop_cache_ctx_t       *ctx;
    ngx_rtmp_gop_frame_t           *frame;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return NULL;
    }

    if (ctx->free_frame) {
        frame = ctx->free_frame;
        ctx->free_frame = frame->next;

        return frame;
    }

    frame = ngx_pcalloc(ctx->pool, sizeof(ngx_rtmp_gop_frame_t));

    return frame;
}


static ngx_rtmp_gop_frame_t *
ngx_rtmp_gop_cache_free_frame(ngx_rtmp_session_t *s,
    ngx_rtmp_gop_frame_t *frame)
{
    ngx_rtmp_core_srv_conf_t       *cscf;
    ngx_rtmp_gop_cache_ctx_t       *ctx;

    cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);
    if (cscf == NULL) {
        return NULL;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return NULL;
    }

    if (frame->frame) {
        ngx_rtmp_free_shared_chain(cscf, frame->frame);
        frame->frame = NULL;
    }

    if (frame->h.type == NGX_RTMP_MSG_VIDEO) {
        ctx->video_frame_in_all--;
    } else if (frame->h.type == NGX_RTMP_MSG_AUDIO) {
        ctx->audio_frame_in_all--;
    }

    ngx_log_debug3(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
           "gop free frame: type='%s' video_frame_in_cache=%uD "
           "audio_frame_in_cache=%uD",
           frame->h.type == NGX_RTMP_MSG_VIDEO ? "video" : "audio",
           ctx->video_frame_in_all, ctx->audio_frame_in_all);

    return frame->next;
}


static ngx_int_t
ngx_rtmp_gop_cache_link_frame(ngx_rtmp_session_t *s,
    ngx_rtmp_gop_frame_t *frame)
{
    ngx_rtmp_gop_cache_ctx_t       *ctx;
    ngx_rtmp_gop_cache_t           *cache;
    ngx_rtmp_gop_frame_t          **iter;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return NGX_ERROR;
    }

    cache = ctx->cache_tail;
    if (cache == NULL) {
        return NGX_ERROR;
    }

    if(cache->frame_head == NULL) {
        cache->frame_head = cache->frame_tail = frame;
    } else {
        iter = &cache->frame_tail->next;
        *iter = frame;
        cache->frame_tail = frame;
    }

    if (frame->h.type == NGX_RTMP_MSG_VIDEO) {
        ctx->video_frame_in_all++;
        cache->video_frame_in_this++;
    } else if(frame->h.type == NGX_RTMP_MSG_AUDIO) {
        ctx->audio_frame_in_all++;
        cache->audio_frame_in_this++;
    }

    ngx_log_debug5(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
            "gop link frame: type='%s' "
            "ctx->video_frame_in_all=%uD "
            "ctx->audio_frame_in_all=%uD "
            "cache->video_frame_in_this=%uD "
            "cache->audio_frame_in_this=%uD",
            frame->h.type == NGX_RTMP_MSG_VIDEO ? "video" : "audio",
            ctx->video_frame_in_all, ctx->audio_frame_in_all,
            cache->video_frame_in_this, cache->audio_frame_in_this);

    return NGX_OK;
}


static ngx_int_t
ngx_rtmp_gop_cache_alloc_cache(ngx_rtmp_session_t *s)
{
    ngx_rtmp_codec_ctx_t           *codec_ctx;
    ngx_rtmp_gop_cache_ctx_t       *ctx;
    ngx_rtmp_gop_cache_t           *cache, **iter;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return NGX_ERROR;
    }

    codec_ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_codec_module);
    if (codec_ctx == NULL) {
        return NGX_ERROR;
    }

    if (ctx->free_cache) {
        cache = ctx->free_cache;
        ctx->free_cache = cache->next;

        ngx_memzero(cache, sizeof(ngx_rtmp_gop_cache_t));
    } else {
        cache = ngx_pcalloc(ctx->pool, sizeof(ngx_rtmp_gop_cache_t));
        if (cache == NULL) {
            return NGX_ERROR;
        }
    }

    if (ctx->cache_head == NULL) {
        ctx->cache_tail = ctx->cache_head = cache;
    } else {
        iter = &ctx->cache_tail->next;
        *iter = cache;
        ctx->cache_tail = cache;
    }

    ctx->gop_cache_count++;

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
           "gop alloc cache: gop_cache_count=%uD", ctx->gop_cache_count);

    return NGX_OK;
}


static ngx_rtmp_gop_cache_t *
ngx_rtmp_gop_cache_free_cache(ngx_rtmp_session_t *s,
    ngx_rtmp_gop_cache_t *cache)
{
    ngx_rtmp_core_srv_conf_t       *cscf;
    ngx_rtmp_gop_cache_ctx_t       *ctx;
    ngx_rtmp_gop_frame_t           *frame;

    cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);
    if (cscf == NULL) {
        return NULL;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return NULL;
    }

    for (frame = cache->frame_head; frame; frame = frame->next) {
        ngx_rtmp_gop_cache_free_frame(s, frame);
    }

    if (cache->video_seq_header) {
        ngx_rtmp_free_shared_chain(cscf, cache->video_seq_header);
        cache->video_seq_header = NULL;
    }

    if (cache->audio_seq_header) {
        ngx_rtmp_free_shared_chain(cscf, cache->audio_seq_header);
        cache->audio_seq_header = NULL;
    }

    if (cache->meta) {
        ngx_rtmp_free_shared_chain(cscf, cache->meta);
        cache->meta_version = 0;
        cache->meta = NULL;
    }

    cache->video_frame_in_this = 0;
    cache->audio_frame_in_this = 0;

    // recycle mem of gop frame
    cache->frame_tail->next = ctx->free_frame;
    ctx->free_frame = cache->frame_head;

    ctx->gop_cache_count--;

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
           "gop free cache: gop_cache_count=%uD", ctx->gop_cache_count);

    return cache->next;
}


static void
ngx_rtmp_gop_cache_cleanup(ngx_rtmp_session_t *s)
{
    ngx_rtmp_gop_cache_ctx_t       *ctx;
    ngx_rtmp_gop_cache_t           *cache;

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return;
    }

    for (cache = ctx->cache_head; cache; cache = cache->next) {
        ngx_rtmp_gop_cache_free_cache(s, cache);
    }

    if (ctx->cache_head) {
        ctx->cache_head->next = ctx->free_cache;
        ctx->free_cache = ctx->cache_head;
        ctx->cache_head = NULL;
    }

    ctx->cache_tail = NULL;
    ctx->gop_cache_count = 0;
    ctx->video_frame_in_all = 0;
    ctx->audio_frame_in_all = 0;
}


static void
ngx_rtmp_gop_cache_update(ngx_rtmp_session_t *s)
{
    ngx_rtmp_gop_cache_app_conf_t        *gacf;
    ngx_rtmp_gop_cache_ctx_t             *ctx;
    ngx_rtmp_gop_cache_t                 *next;

    gacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_gop_cache_module);
    if (gacf == NULL) {
        return;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return;
    }

    while (ctx->gop_cache_count > gacf->gop_cache_count) {
        if (ctx->cache_head) {
            /* remove the 1st gop */
            next = ngx_rtmp_gop_cache_free_cache(s, ctx->cache_head);

            ctx->cache_head->next = ctx->free_cache;
            ctx->free_cache = ctx->cache_head;

            ctx->cache_head = next;
        }
    }
}


static void
ngx_rtmp_gop_cache_frame(ngx_rtmp_session_t *s, ngx_uint_t prio,
    ngx_rtmp_header_t *ch, ngx_chain_t *frame)
{
    ngx_rtmp_gop_cache_ctx_t       *ctx;
    ngx_rtmp_codec_ctx_t           *codec_ctx;
    ngx_rtmp_core_srv_conf_t       *cscf;
    ngx_rtmp_gop_cache_app_conf_t  *gacf;
    ngx_rtmp_gop_frame_t           *gf;

    gacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_gop_cache_module);
    if (gacf == NULL || !gacf->gop_cache) {
        return;
    }

    cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);
    if (cscf == NULL) {
        return;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        return;
    }

    codec_ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_codec_module);
    if (codec_ctx == NULL) {
        return;
    }

    if (ch->type == NGX_RTMP_MSG_VIDEO) {
        // drop non-IDR
        if (prio != NGX_RTMP_VIDEO_KEY_FRAME && ctx->cache_head == NULL) {
            ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                    "gop cache: drop video non-keyframe timestamp=%uD",
                    ch->timestamp);

            return;
        }
    }

    // audio only
    if (ctx->video_frame_in_all == 0 && ch->type == NGX_RTMP_MSG_AUDIO) {
        ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "gop cache: drop audio frame timestamp=%uD",
                       ch->timestamp);

        return;
    }

    if (ch->type == NGX_RTMP_MSG_VIDEO && prio == NGX_RTMP_VIDEO_KEY_FRAME) {
        if (ngx_rtmp_gop_cache_alloc_cache(s) != NGX_OK) {
            return;
        }
    }

    // save video seq header.
    if (codec_ctx->avc_header &&
        (ctx->cache_tail && ctx->cache_tail->video_seq_header == NULL))
    {
        ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "gop cache: add video seq header in new cache");
        ctx->cache_tail->video_seq_header = codec_ctx->avc_header;
        ngx_rtmp_acquire_shared_chain(ctx->cache_tail->video_seq_header);
    }

    // save audio seq header.
    if (codec_ctx->aac_header &&
        (ctx->cache_tail && ctx->cache_tail->audio_seq_header == NULL))
    {
        ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "gop cache: add audio seq header in new cache");
        ctx->cache_tail->audio_seq_header = codec_ctx->aac_header;
        ngx_rtmp_acquire_shared_chain(ctx->cache_tail->audio_seq_header);
    }

    // save metadata.
    if (codec_ctx->meta &&
        (ctx->cache_tail && ctx->cache_tail->meta == NULL))
    {
        ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                       "gop cache: add meta in new cache, version=%ui",
                       codec_ctx->meta_version);
        ctx->cache_tail->meta_version = codec_ctx->meta_version;
        ctx->cache_tail->meta = codec_ctx->meta;
        ngx_rtmp_acquire_shared_chain(ctx->cache_tail->meta);
    }

    gf = ngx_rtmp_gop_cache_alloc_frame(s);
    if (gf == NULL) {
        return;
    }

    gf->h = *ch;
    gf->prio = prio;
    gf->next = NULL;
    gf->frame = ngx_rtmp_append_shared_bufs(cscf, NULL, frame);

    if (ngx_rtmp_gop_cache_link_frame(s, gf) != NGX_OK) {
        ngx_rtmp_free_shared_chain(cscf, gf->frame);
        return;
    }

    if (ctx->video_frame_in_all > gacf->gop_max_video_count ||
        ctx->audio_frame_in_all > gacf->gop_max_audio_count ||
        (ctx->video_frame_in_all + ctx->audio_frame_in_all)
        > gacf->gop_max_frame_count)
    {
        ngx_log_error(NGX_LOG_WARN, s->connection->log, 0,
               "gop cache: video_frame_in_cache=%uD "
               "audio_frame_in_cache=%uD max_video_count=%uD "
               "max_audio_count=%uD gop_max_frame_count=%uD",
               ctx->video_frame_in_all, ctx->audio_frame_in_all,
               gacf->gop_max_video_count, gacf->gop_max_audio_count,
               gacf->gop_max_frame_count);

        ngx_rtmp_gop_cache_cleanup(s);
        return;
    }

    ngx_rtmp_gop_cache_update(s);

    ngx_log_debug2(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
           "gop cache: cache packet type='%s' timestamp=%uD",
           gf->h.type == NGX_RTMP_MSG_AUDIO ? "audio" : "video",
           gf->h.timestamp);
}


static void
ngx_rtmp_gop_cache_send(ngx_rtmp_session_t *s)
{
    ngx_rtmp_session_t                 *rs;
    ngx_chain_t                        *pkt, *apkt, *acopkt, *meta;
    ngx_chain_t                        *header, *coheader;
    ngx_rtmp_live_ctx_t                *ctx, *pub_ctx;
    ngx_http_flv_live_ctx_t            *hflctx;
    ngx_rtmp_gop_cache_ctx_t           *gctx;
    ngx_rtmp_live_app_conf_t           *lacf;
    ngx_rtmp_gop_cache_t               *cache;
    ngx_rtmp_gop_frame_t               *gf;
    ngx_rtmp_header_t                   ch, lh, clh;
    ngx_uint_t                          meta_version;
    uint32_t                            delta;
    ngx_int_t                           csidx;
    ngx_rtmp_live_chunk_stream_t       *cs;
    ngx_rtmp_live_proc_handler_t       *handler;
    ngx_http_request_t                 *r;
    ngx_rtmp_codec_ctx_t               *codec_ctx;
    ngx_flag_t                          mandatory, error;

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

    /* pub_ctx saved the publisher info */
    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx == NULL || ctx->stream == NULL ||
        ctx->stream->pub_ctx == NULL || !ctx->stream->publishing) {
        return;
    }

    pkt = NULL;
    apkt = NULL;
    acopkt = NULL;
    header = NULL;
    coheader = NULL;
    meta_version = 0;

    pub_ctx = ctx->stream->pub_ctx;
    rs = pub_ctx->session;
    s->publisher = rs;
    handler = ngx_rtmp_live_proc_handlers[ctx->protocol];

    if (rs == NULL) {
        return;
    }

    gctx = ngx_rtmp_get_module_ctx(rs, ngx_rtmp_gop_cache_module);
    if (gctx == NULL) {
        return;
    }

    codec_ctx = ngx_rtmp_get_module_ctx(rs, ngx_rtmp_codec_module);
    if (codec_ctx == NULL) {
        return;
    }

    for (cache = gctx->cache_head; cache; cache = cache->next) {
        if (s->connection == NULL || s->connection->destroyed) {
            return;
        }

        if (ctx->protocol == NGX_RTMP_PROTOCOL_HTTP) {
            r = s->data;
            if (r == NULL) {
                return;
            }

            hflctx = ngx_http_get_module_ctx(r, ngx_http_flv_live_module);
            if (!hflctx->header_sent) {
                hflctx->header_sent = 1;
                ngx_http_flv_live_send_header(s);
            }
        }

        meta = NULL;

        if (cache->meta && meta_version != cache->meta_version) {
            meta = handler->meta_message_pt(s, cache->meta);
            if (meta == NULL) {
                ngx_rtmp_finalize_session(s);
                return;
            }

            meta_version = cache->meta_version;
        }

        /* send metadata */
        if (meta && meta_version != ctx->meta_version) {
            ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                           "gop cache send: meta, version=%ui", meta_version);

            if (handler->send_message_pt(s, meta, 0) == NGX_ERROR) {
                ngx_rtmp_finalize_session(s);
                return;
            }

            ctx->meta_version = meta_version;
            handler->free_message_pt(s, meta);
        }

        for (gf = cache->frame_head; gf; gf = gf->next) {
            if (s->connection == NULL || s->connection->destroyed) {
                return;
            }

            csidx = !(lacf->interleave || gf->h.type == NGX_RTMP_MSG_VIDEO);

            cs = &ctx->cs[csidx];

            lh = ch = gf->h;

            if (cs->active) {
                lh.timestamp = cs->timestamp;
            }

            clh = lh;
            clh.type = (gf->h.type == NGX_RTMP_MSG_AUDIO ? NGX_RTMP_MSG_VIDEO :
                                                           NGX_RTMP_MSG_AUDIO);

            delta = ch.timestamp - lh.timestamp;
            mandatory = 0;
            error = 0;

            if (ch.type == NGX_RTMP_MSG_AUDIO) {
                if (codec_ctx->audio_codec_id == NGX_RTMP_AUDIO_AAC &&
                    ngx_rtmp_is_codec_header(gf->frame))
                {
                    mandatory = 1;
                }
            } else {
                if (codec_ctx->video_codec_id == NGX_RTMP_VIDEO_H264 &&
                    ngx_rtmp_is_codec_header(gf->frame))
                {
                    mandatory = 1;
                }
            }

            if (!cs->active) {
                if (mandatory) {
                    ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                                   "gop cache: skipping header");

                    continue;
                }

                switch (gf->h.type) {
                    case NGX_RTMP_MSG_VIDEO:
                        header = cache->video_seq_header;
                        if (lacf->interleave) {
                            coheader = cache->audio_seq_header;
                        }
                        break;
                    default:
                        header = cache->audio_seq_header;
                        if (lacf->interleave) {
                            coheader = cache->video_seq_header;
                        }
                }

                if (header) {
                    apkt = handler->append_message_pt(s, &lh, NULL, header);
                    if (apkt == NULL) {
                        error = 1;
                        goto next;
                    }
                }

                if (apkt && handler->send_message_pt(s, apkt, 0) != NGX_OK) {
                    goto next;
                }

                if (coheader) {
                    acopkt = handler->append_message_pt(s, &clh, NULL,
                                                        coheader);
                    if (acopkt == NULL) {
                        error = 1;
                        goto next;
                    }
                }

                if (acopkt && handler->send_message_pt(s, acopkt, 0) != NGX_OK) {
                    goto next;
                }

                cs->timestamp = lh.timestamp;
                cs->active = 1;
                s->current_time = cs->timestamp;
            }

            pkt = handler->append_message_pt(s, &ch, &lh, gf->frame);
            if (pkt == NULL) {
                error = 1;
                goto next;
            }

            if (handler->send_message_pt(s, pkt, gf->prio) != NGX_OK) {
                ++pub_ctx->ndropped;

                cs->dropped += delta;

                if (mandatory) {
                    ngx_log_debug0(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                                   "gop cache send: mandatory packet failed");

                    error = 1;
                }

                goto next;
            }

            ngx_log_debug4(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
                    "gop cache send: tag type='%s' prio=%d ctimestamp=%uD "
                    "ltimestamp=%uD",
                    gf->h.type == NGX_RTMP_MSG_AUDIO ? "audio" : "video",
                    gf->prio, ch.timestamp, lh.timestamp);

            cs->timestamp += delta;
            s->current_time = cs->timestamp;

        next:

            if (pkt) {
                handler->free_message_pt(s, pkt);
                pkt = NULL;
            }

            if (apkt) {
                handler->free_message_pt(s, apkt);
                apkt = NULL;
            }

            if (acopkt) {
                handler->free_message_pt(s, acopkt);
                acopkt = NULL;
            }

            if (error) {
                ngx_rtmp_finalize_session(s);
                return;
            }
        }
    }
}


static ngx_int_t
ngx_rtmp_gop_cache_av(ngx_rtmp_session_t *s, ngx_rtmp_header_t *h,
    ngx_chain_t *in)
{
    ngx_rtmp_live_ctx_t            *ctx;
    ngx_rtmp_gop_cache_app_conf_t  *gacf;
    ngx_rtmp_live_app_conf_t       *lacf;
    ngx_rtmp_live_chunk_stream_t   *cs;
    ngx_rtmp_header_t               ch;
    ngx_uint_t                      prio;
    ngx_uint_t                      csidx;

    gacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_gop_cache_module);
    if (gacf == NULL || !gacf->gop_cache) {
        return NGX_OK;
    }

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

    if (in == NULL || in->buf == NULL) {
        return NGX_OK;
    }

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_live_module);
    if (ctx == NULL || ctx->stream == NULL) {
        return NGX_OK;
    }

    if (!ctx->publishing) {
        return NGX_OK;
    }

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

    csidx = !(lacf->interleave || h->type == NGX_RTMP_MSG_VIDEO);

    cs = &ctx->cs[csidx];

    ngx_memzero(&ch, sizeof(ch));

    ch.timestamp = h->timestamp;
    ch.msid = NGX_RTMP_MSID;
    ch.csid = cs->csid;
    ch.type = h->type;

    ngx_rtmp_gop_cache_frame(s, prio, &ch, in);

    return NGX_OK;
}


static ngx_int_t
ngx_rtmp_gop_cache_publish(ngx_rtmp_session_t *s, ngx_rtmp_publish_t *v)
{
    ngx_rtmp_live_ctx_t            *lctx;
    ngx_rtmp_gop_cache_app_conf_t  *gacf;
    ngx_rtmp_gop_cache_ctx_t       *ctx;

    gacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_gop_cache_module);
    if (gacf == NULL || !gacf->gop_cache) {
        goto next;
    }

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

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

    ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (ctx == NULL) {
        ctx = ngx_pcalloc(s->connection->pool,
                          sizeof(ngx_rtmp_gop_cache_ctx_t));
        if (ctx == NULL) {
            ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
                          "gop cache publish: failed to allocate for ctx");

            return NGX_ERROR;
        }

        ctx->pool = ngx_create_pool(NGX_GOP_CACHE_POOL_CREATE_SIZE,
                                    s->connection->log);
        if (ctx->pool == NULL) {
            return NGX_ERROR;
        }

        ngx_rtmp_set_ctx(s, ctx, ngx_rtmp_gop_cache_module);
    }

next:
    return next_publish(s, v);
}


static ngx_int_t
ngx_rtmp_gop_cache_play(ngx_rtmp_session_t *s, ngx_rtmp_play_t *v)
{
    ngx_rtmp_gop_cache_app_conf_t  *gacf;
#ifdef NGX_DEBUG
    ngx_msec_t                      start, end;
#endif

    gacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_gop_cache_module);
    if (gacf == NULL || !gacf->gop_cache) {
        goto next;
    }

    ngx_log_debug4(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
            "gop cache play: name='%s' start=%i duration=%i reset=%d",
            v->name, (ngx_int_t) v->start,
            (ngx_int_t) v->duration, (ngx_uint_t) v->reset);

#ifdef NGX_DEBUG
    start = ngx_current_msec;
    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
            "gop cache send: start_time=%uD", start);
#endif

    ngx_rtmp_gop_cache_send(s);

#ifdef NGX_DEBUG
    end = ngx_current_msec;
    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
            "gop cache send: end_time=%uD", end);

    ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
            "gop cache send: delta_time=%uD", end - start);
#endif

next:
    return next_play(s, v);
}


static ngx_int_t
ngx_rtmp_gop_cache_close_stream(ngx_rtmp_session_t *s,
    ngx_rtmp_close_stream_t *v)
{
    ngx_rtmp_live_ctx_t            *ctx;
    ngx_rtmp_gop_cache_ctx_t       *gctx;
    ngx_rtmp_live_app_conf_t       *lacf;
    ngx_rtmp_gop_cache_app_conf_t  *gacf;

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

    if (!ctx->publishing) {
        goto next;
    }

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

    gacf = ngx_rtmp_get_module_app_conf(s, ngx_rtmp_gop_cache_module);
    if (gacf == NULL || !gacf->gop_cache) {
        goto next;
    }

    ngx_rtmp_gop_cache_cleanup(s);

    gctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_gop_cache_module);
    if (gctx == NULL) {
        goto next;
    }

    if (gctx->pool) {
        ngx_destroy_pool(gctx->pool);
        gctx->pool = NULL;
    }

next:
    return next_close_stream(s, v);
}


static ngx_int_t
ngx_rtmp_gop_cache_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 */

    h = ngx_array_push(&cmcf->events[NGX_RTMP_MSG_AUDIO]);
    *h = ngx_rtmp_gop_cache_av;

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

    next_publish = ngx_rtmp_publish;
    ngx_rtmp_publish = ngx_rtmp_gop_cache_publish;

    next_play = ngx_rtmp_play;
    ngx_rtmp_play = ngx_rtmp_gop_cache_play;

    next_close_stream = ngx_rtmp_close_stream;
    ngx_rtmp_close_stream = ngx_rtmp_gop_cache_close_stream;

    return NGX_OK;
}