第三方发表素材文章时，content字段会自动过滤掉iframe

上传时content为

<section><iframe class="video_iframe rich_pages" data-vidtype="2" data-mpvid="wxv_1681892499969130499" data-cover="http%3A%2F%2Fmmbiz.qpic.cn%2Fmmbiz_jpg%2Fv1fXoxic4bPe4ZAjLMskcgd8CGiaTSn9NnuOGWJP9LD6iadyIFJJssGeA3xTvdcTibElT6tBkDM31c9W5cVSHdV8icA%2F0%3Fwx_fmt%3Djpeg" allowfullscreen="" frameborder="0" style="  z-index:1; " data-ratio="1.7777777777777777" data-w="1920" src="https://mp.weixin.qq.com/mp/readtemplate?t=pages/video_player_tmpl&action=mpvideo&auto=0&vid=wxv_1681892499969130499"></iframe></section><br/>

返回content为

<section><iframe class="video_iframe rich_pages" data-vidtype="2" data-mpvid="wxv_1681892499969130499" data-cover="http%3A%2F%2Fmmbiz.qpic.cn%2Fmmbiz_jpg%2Fv1fXoxic4bPe4ZAjLMskcgd8CGiaTSn9NnuOGWJP9LD6iadyIFJJssGeA3xTvdcTibElT6tBkDM31c9W5cVSHdV8icA%2F0%3Fwx_fmt%3Djpeg" allowfullscreen="" frameborder="0" style="  z-index:1; " data-ratio="1.7777777777777777" data-w="1920"></iframe></section><br  />

请问如何处理这一类的情况？