PHP Json декодирует пустой

пытается расшифровать допустимую строку Json. Но не удалось с PHP: Интернет-песочница: http://sandbox.onlinephpfunctions.com/code/a7c76cad0116a4ab9621cd1b7d689e34042b8bc8

Не удается найти синтаксическую ошибку

$json='{"before_after":{"name":"before_after","path":".\\(Footage)\\_photos\\photo\\","title":"Before After","slideDesc":"use this Template for Before After Videos","slideNum":12,"snipSets":3,"snipTextMax":8,"snipTextMin":1,"durationslide":{"active":0,"min":20,"max":999,"default":60},"durationsnip":{"active":1,"min":3,"max":12,"default":4},"slideSet":[{"mod":"text","label":"Add Title","label2":"Title"},{"mod":"text","label":"Add Desc","label2":"Desc"},{"mod":"media","label":"Add Teaser","label2":"Teaser"}],"snipSet":[{"mod":"media","text":"Add Pic","label":"Before Media"},{"mod":"media","text":"Add Pic","label":"After Media"},{"mod":"text","text":"Before text","label":"Before Text"},{"mod":"text","text":"After text","label":"After Text"}]},"toplist":{"name":"toplist","path":".\\(Footage)\\_photos\\photo\\","title":"Top Liste","slideDesc":"use this Template for a Top List of Contents","slideNum":12,"snipSets":3,"snipTextMax":8,"snipTextMin":1,"durationslide":{"active":0,"min":20,"max":999,"default":60},"durationsnip":{"active":1,"min":3,"max":12,"default":4},"slideSet":[{"mod":"text","label":"Slide Title","label2":"Title"},{"mod":"text","label":"Slide Description","label2":"Description"},{"mod":"media","label":"Add  Teaser","label2":"Teaser"}],"snipSet":[{"mod":"media","text":"Add Picture","label":"Pic 1"},{"mod":"text","text":"Add text","label":"Picture Text"}]},"timeline":{"name":"timeline","title":"Timeline","path":".\\(Footage)\\_photos\\photo\\","slideDesc":"use this Template for a Timeline","slideNum":12,"snipSets":3,"snipTextMax":8,"snipTextMin":1,"durationslide":{"active":0,"min":20,"max":999,"default":60},"durationsnip":{"active":1,"min":3,"max":12,"default":4},"slideSet":[{"mod":"text","label":"Timeperiod Title","label2":"Title"},{"mod":"text","label":"Slide Description","label2":"Description"},{"mod":"text","label":"Time 2017","label2":"Time 1929","attr":{"type":"number","min":"-4000","max":"2500","required":"required"}},{"mod":"media","label":"Add Teaser","label2":"Teaser"}],"snipSet":[{"mod":"media","text":"Add Picture","label":"Pic 1"},{"mod":"text","text":"Add text","label":"Picture Text"}]}}';
print_r(json_decode($json));//empty