这是我从 youtube 移动网站检索到的字符串。我想使用 php 提取 json。
$str = ")]}'{\"conn\": \"wifi\", \"content\": {\"pyv_ping_url\": null, \"subscription_state\": {\"subscribe_url\": {\"url\": \"\\\/channel_post?feature=watch\\u0026action_subscribe=1\", \"channel_id\": \"UCeQEKFH31vvD-InkTGSvCrA\"}, \"show_button\": true, \"is_subscribed\": false}, \"distiller_config\": {\"owner_id\": \"eQEKFH31vvD-InkTGSvCrA\", \"visible\": null, \"pinned_activity\": null, \"channel_id\": \"UCeQEKFH31vvD-InkTGSvCrA\", \"privacy_setting\": \"PUBLIC\", \"query\": \"http:\\\/\\\/www.youtube.com\\\/watch?v=C5tOEBmBAHg\", \"signin_url\": \"https:\\\/\\\/accounts.google.com\\\/ServiceLogin?service=youtube\\u0026passive=true\\u0026uilel=3\\u0026hl=en_US\\u0026ltmpl=mobile\\u0026continue=http%3A%2F%2Fm.youtube.com%2Fsignin%3Faction_handle_signin%3Dtrue%26feature%3Ddistiller%26hl%3Den_US%26next%3D%252Fwatch%253Fv%253DC5tOEBmBAHg%2526client%253Dmv-google%26nomobiletemp%3D1\", \"video_id\": \"C5tOEBmBAHg\", \"debug\": false, \"filter_premod\": false}, \"allow_comments\": true, \"ad_instream\": \"\", \"show_pyv_in_related\": false, \"player_data\":
{\"fmt_stream_map\": [{\"itag\": \"18\", \"type\": \"video\\\/mp4; codecs=\\\"avc1.42001E, mp4a.40.2\\\"\", \"fallback_host\": \"tc.v6.cache1.c.youtube.com\", \"quality\": \"medium\", \"url\": \"http:\\\/\\\/r4---sn-nau-jhcl.c.youtube.com\\\/videoplayback?ms=au\\u0026itag=18\\u0026mt=1378896627\\u0026app=youtube_mobile\\u0026mv=m\\u0026source=youtube\\u0026sver=3\\u0026expire=1378918433\\u0026sparams=cp%2Cid%2Cip%2Cipbits%2Citag%2Cratebypass%2Csource%2Cupn%2Cexpire\\u0026cp=U0hWTVlMVl9ITUNONl9RRlpFOkV6dktxMFVBYU1Y\\u0026upn=kjDilUW5IQE\\u0026ip=124.43.93.65\\u0026dnc=1\\u0026el=watch\\u0026yms=FcwHm3XWaNY\\u0026ratebypass=yes\\u0026key=yt1\\u0026signature=06D949BF71135F49A3BE9E7A47182B2A61DCF915.5B86FC625C760F1402BC700C660E61CC69684992\\u0026id=0b9b4e1019810078\\u0026fexp=907724%2C906942%2C924606%2C929117%2C929121%2C929906%2C929907%2C929922%2C929127%2C929129%2C929131%2C929930%2C936403%2C925726%2C936310%2C925720%2C925722%2C925718%2C925714%2C929917%2C906945%2C929933%2C920302%2C906842%2C913428%2C919811%2C913563%2C919373%2C930803%2C908536%2C938701%2C931924%2C936308%2C909549%2C900816%2C912711%2C904494%2C904497%2C939903%2C900375%2C900382%2C934507%2C907231%2C936312%2C906001\\u0026ipbits=8\"}, {\"itag\": \"36\", \"type\": \"video\\\/3gpp; codecs=\\\"mp4v.20.3, mp4a.40.2\\\"\", \"fallback_host\": \"tc.v23.cache2.c.youtube.com\", \"quality\": \"small\",
\"url\": \"http:\\\/\\\/r4---sn-nau-jhcl.c.youtube.com\\\/videoplayback?ms=au\\u0026itag=36\\u0026mt=1378896627\\u0026app=youtube_mobile\\u0026mv=m\\u0026source=youtube\\u0026sver=3\\u0026expire=1378918433\\u0026sparams=cp%2Cid%2Cip%2Cipbits%2Citag%2Cratebypass%2Csource%2Cupn%2Cexpire\\u0026cp=U0hWTVlMVl9ITUNONl9RRlpFOkV6dktxMFVBYU1Y\\u0026upn=kjDilUW5IQE\\u0026ip=124.43.93.65\\u0026dnc=1\\u0026el=watch\\u0026yms=FcwHm3XWaNY\\u0026ratebypass=yes\\u0026key=yt1\\u0026signature=663C16B74F22132913A4E86CFE733CEFC10C18C3.175EA19B37241399C17305FAACEFB07A1C5FB2DD\\u0026id=0b9b4e1019810078\\u0026fexp=907724%2C906942%2C924606%2C929117%2C929121%2C929906%2C929907%2C929922%2C929127%2C929129%2C929131%2C929930%2C936403%2C925726%2C936310%2C925720%2C925722%2C925718%2C925714%2C929917%2C906945%2C929933%2C920302%2C906842%2C913428%2C919811%2C913563%2C919373%2C930803%2C908536%2C938701%2C931924%2C936308%2C909549%2C900816%2C912711%2C904494%2C904497%2C939903%2C900375%2C900382%2C934507%2C907231%2C936312%2C906001\\u0026ipbits=8\"}], \"playability\": \"PLAY_OK\", \"player_type\": \"html5fs\"}, \"subscribe_xsrf_token\": \"V-JkAZNXVIi4gjwRIRaUyy1rqh98MTM3ODk4MzA2MUAxMzc4ODk2NjYx\", \"channel_subscriber_count\": 1445686, \"should_prompt_merge_identity\": false, \"branding\": null, \"sentiment_xsrf_token\": \"rUe1DX9B6S0kBEJwaYYRBQkgw1J8MTM3ODk4MzA2MUAxMzc4ODk2NjYx\", \"ptracking\": \"\\\/\\\/www.youtube.com\\\/ptracking?ptk=brusspup%252Buser\\u0026pltype=content\\u0026oid=3OmbD_Dz3bv1YwNAoU8c6A\\u0026ptchn=brusspup\\u0026video_id=C5tOEBmBAHg\", \"next_url\": \"\\\/related?v=C5tOEBmBAHg\\u0026page=2\", \"allow_ratings\": true, \"video\": {\"user_image_url\": \"\\\/\\\/i1.ytimg.com\\\/i\\\/eQEKFH31vvD-InkTGSvCrA\\\/1.jpg?v=4efb5240\", \"time_created_text\": \"Sep 4, 2013\", \"duration\": \"2:09\", \"view_count\": \"2,767,499\", \"title\": \"Incredible Chemical Reaction!\", \"thumbnail_info\": null, \"comment_count\": 4367, \"dislikes_num\": 1203, \"longform\": false, \"profile_url\": \"\\\/user\\\/brusspup\", \"thumbnail_for_watch\": \"http:\\\/\\\/i.ytimg.com\\\/vi\\\/C5tOEBmBAHg\\\/hqdefault.jpg?w=320\\u0026h=192\\u0026sigh=yvFlZe6HDNoAvIPVEiRBbyEUDAw\", \"likes_num\": 21801, \"watch_link\": \"\\\/watch?v=C5tOEBmBAHg\", \"encrypted_id\": \"C5tOEBmBAHg\", \"description\": \"Add me on Facebook. (click LIKE on Facebook to add me) \\nhttp:\\\/\\\/www.facebook.com\\\/brusspup\\n\\n\\nDownload the song in this video:\\nSong name: Monolith\\n\\niTunes\\nhttps:\\\/\\\/itunes.apple.com\\\/us\\\/album\\\/monolith-single\\\/id596457486\\n\\nAmazon\\nhttp:\\\/\\\/www.amazon.com\\\/Monolith\\\/dp\\\/B00B60NGFY\\\/ref=sr_1_1?ie=UTF8\\u0026qid=1378343773\\u0026sr=8-1\\u0026keywords=monolith+brusspup\\n\\nThere are no editing tricks in the video. All of the reactions that you see are uncut and play at the original speed.\\n\\nThis is a classic chemical reaction. It's called the iodine clock reaction. There are several variations of how this chemical reaction can be performed using different chemicals than the ones I used in the video. You can order clock reaction kits from several science related websites. You can also use simple store bought chemicals like vitamin C, iodine, hydrogen peroxide and starch. A quick internet search will turn up multiple ways of performing the experiment.\\n\\nEven though I've played around with the clock reaction experiment before I've always wanted to capture the reaction as the liquid was being poured. To me, this is the most stunning way of demonstrating the reaction.\\n\\nHere's the other version of the clock reaction I made several years ago\\nhttp:\\\/\\\/www.youtube.com\\\/watch?v=qeDhaWEEvfg\", \"length_seconds\": 129, \"public_name\": \"brusspup\"}, \"related_videos\": [{\"duration\": \"2:40\", \"view_count\": \"411,584\", \"title\": \"Amazing Hologram Effect!\", \"thumbnail_info\": {\"posx\": 0, \"posy\": 0, \"stitched\": 1, \"width\": 128, \"height\": 880, \"thumb_height\": 72, \"url\": \"http:\\\/\\\/i.ytimg.com\\\/vt?cids=WllhvcRH3KM,8tHOVVgGkpk,wvJAgrUBF4w,1yaqUI4b974,hq8j86OenqM,xVyYcAI90jw,vZaRgMOo-Ig,dMuGAmdr8m4,uENITui5_jU,hSorsJ-lRYk,kf1xFCcvadg\\u0026w=120\\u0026h=72\\u0026sigh=c99tZpvMiwZDzKB_NwFL5pdZ3QM\", \"thumb_width\": 120}, \"related_feature\": \"relmfu\", \"thumbnail_for_watch\": \"http:\\\/\\\/i.ytimg.com\\\/vi\\\/WllhvcRH3KM\\\/hqdefault.jpg?w=320\\u0026h=192\\u0026sigh=t18Qmilb_rFtwJKJTBCKbaRLQyo\", \"playability\": \"NO_PREFETCH\", \"watch_link\": \"\\\/watch?v=WllhvcRH3KM\\u0026feature=relmfu\", \"encrypted_id\": \"WllhvcRH3KM\", \"public_name\": \"brusspup\"}, {\"duration\": \"2:21\", \"view_count\": \"2,589,152\", \"title\": \"Giant Dry Ice Bubble Experiment!\", \"thumbnail_info\": {\"posx\": 0, \"posy\": 80, \"stitched\": 1, \"width\": 128, \"height\": 880, \"thumb_height\": 72, \"url\": \"http:\\\/\\\/i.ytimg.com\\\/vt?cids=WllhvcRH3KM,8tHOVVgGkpk,wvJAgrUBF4w,1yaqUI4b974,hq8j86OenqM,xVyYcAI90jw,vZaRgMOo-Ig,dMuGAmdr8m4,uENITui5_jU,hSorsJ-lRYk,kf1xFCcvadg\\u0026w=120\\u0026h=72\\u0026sigh=c99tZpvMiwZDzKB_NwFL5pdZ3QM\", \"thumb_width\": 120}, \"related_feature\": \"relmfu\", \"thumbnail_for_watch\": \"http:\\\/\\\/i.ytimg.com\\\/vi\\\/8tHOVVgGkpk\\\/hqdefault.jpg?w=320\\u0026h=192\\u0026sigh=hITPLWQ4XEdyqU3OAuySRYY0jRA\", \"playability\": \"NO_PREFETCH\", \"watch_link\": \"\\\/watch?v=8tHOVVgGkpk\\u0026feature=relmfu\", \"encrypted_id\": \"8tHOVVgGkpk\", \"public_name\": \"brusspup\"}, {\"duration\": \"3:39\", \"view_count\": \"3,529,768\", \"title\": \"Amazing Resonance Experiment!\", \"thumbnail_info\": {\"posx\": 0, \"posy\": 160, \"stitched\": 1, \"width\": 128, \"height\": 880, \"thumb_height\": 72, \"url\": \"http:\\\/\\\/i.ytimg.com\\\/vt?cids=WllhvcRH3KM,8tHOVVgGkpk,wvJAgrUBF4w,1yaqUI4b974,hq8j86OenqM,xVyYcAI90jw,vZaRgMOo-Ig,dMuGAmdr8m4,uENITui5_jU,hSorsJ-lRYk,kf1xFCcvadg\\u0026w=120\\u0026h=72\\u0026sigh=c99tZpvMiwZDzKB_NwFL5pdZ3QM\", \"thumb_width\": 120}, \"related_feature\": \"relmfu\", \"thumbnail_for_watch\": \"http:\\\/\\\/i.ytimg.com\\\/vi\\\/wvJAgrUBF4w\\\/hqdefault.jpg?w=320\\u0026h=192\\u0026sigh=jNtSWzQ8HbjFb5KQ27wggqmLmlc\", \"playability\": \"NO_PREFETCH\", \"watch_link\": \"\\\/watch?v=wvJAgrUBF4w\\u0026feature=relmfu\", \"encrypted_id\": \"wvJAgrUBF4w\", \"public_name\": \"brusspup\"}, {\"duration\": \"8:20\", \"view_count\": \"334,912\", \"title\": \"Resonance Experiment! 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