[fix] fixed duplicate writing of audio & video sequence headers.

Privously, audio & video sequence headers were extracted as `avc_header`
and `aac_header` in codec module, then in record module, `avc_header` &
`aac_header` were firstly written. If `in` chain itself is the sequence
header, audio & video sequence header were duplicatively written.

Author: winshining

ngx_rtmp_record_module.c

@@ -1187,6 +1187,11 @@ ngx_rtmp_record_node_av(ngx_rtmp_session_t *s, ngx_rtmp_record_rec_ctx_t *rctx,
             return NGX_OK;
         }
 
+        if (ngx_rtmp_is_codec_header(in)) {
+            ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+                          "record: video header has been written already");
+            return NGX_OK;
+        }
     } else {
         if (codec_ctx && codec_ctx->audio_codec_id == NGX_RTMP_AUDIO_AAC &&
             !rctx->aac_header_sent)
@@ -1195,6 +1200,12 @@ ngx_rtmp_record_node_av(ngx_rtmp_session_t *s, ngx_rtmp_record_rec_ctx_t *rctx,
                            "record: %V skipping until AAC header", &rracf->id);
             return NGX_OK;
         }
+
+        if (ngx_rtmp_is_codec_header(in)) {
+            ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+                          "record: audio header has been written already");
+            return NGX_OK;
+        }
     }
 
     return ngx_rtmp_record_write_frame(s, rctx, h, in, 1);