Range filter: single_range flag in request. If set, it means that response body is going to be in more than one buffer, hence only range requests with a single range should be honored. The flag is now used by mp4 and cacheable upstream responses, thus allowing range requests of mp4 files with start/end, as well as range processing on a first request to a not-yet-cached files with proxy_cache. Notably this makes it possible to play mp4 files (with proxy_cache, or with mp4 module) on iOS devices, as byte-range support is required by Apple.

--- a/src/http/modules/ngx_http_mp4_module.c
+++ b/src/http/modules/ngx_http_mp4_module.c
@@ -571,7 +571,7 @@ ngx_http_mp4_handler(ngx_http_request_t 
     }
 
     if (start >= 0) {
-        r->allow_ranges = 0;
+        r->single_range = 1;
 
         mp4 = ngx_pcalloc(r->pool, sizeof(ngx_http_mp4_file_t));
         if (mp4 == NULL) {