diff --git a/docs/html/http/ngx_http_mp4_module.html b/docs/html/http/ngx_http_mp4_module.html new file mode 100644 index 000000000..1435ef3d4 --- /dev/null +++ b/docs/html/http/ngx_http_mp4_module.html @@ -0,0 +1,90 @@ +HTTP MP4 Module

HTTP MP4 Module

Summary

+The module ngx_http_mp4_module provides pseudo-streaming +server-side support for H.264/AAC files typically having filename extensions +.mp4, .m4v, +and .m4a. +

+Pseudo-streaming works in alliance with conformant Flash players. +A player sends an HTTP request to the server with a start time +argument in the request URI’s query string (named simply +start +and specified in seconds), and the server responds with a stream +so that its start position corresponds to the requested time, +for example: +

+http://example.com/elephants_dream.mp4?start=238.88
+
+This allows for a random seeking at any time, or starting playback +in the middle of a timeline. +

+To support seeking, H.264-based formats store the metadata +in the so-called “moov atom.” +It is a part of the file that holds the index information for the +whole file. +

+To start playback, a player first needs to read metadata. +This is done by sending a special request with the +start=0 +argument. Many encoding software will insert the metadata at +the end of the file. This is bad for pseudo-streaming: +the metadata needs to be located at the beginning of the file, +or else the entire file will have to be downloaded before it +starts playing. If a file is well-formed (with metadata at the +beginning of a file), nginx just sends back the contents of a file. +Otherwise, it has to read the file and prepare a new stream so that +metadata comes before media data. +This involves some CPU, memory, and disk I/O overhead, +so it is a good idea to + +prepare an original file for pseudo-streaming, +rather than having nginx do this on every such request. +

+For a matching request with a non-zero +start +argument, nginx will read metadata from the file, prepare the +stream starting from the requested offset, and send it to a client. +This has the same overhead as described above. +

+If a matching request does not include the +start +argument, there is no overhead, and the file is just sent as a static resource. +Some players also support byte-range requests, and thus do not require +this module at all. +

+This module is not built by default, it should be enabled with the +--with-http_mp4_module +configuration parameter. + +If you were using the third-party mp4 module, be sure to disable it. +

+A similar pseudo-streaming support for FLV files is provided by the module +ngx_http_flv_module. +

Example Configuration

+location /video/ {
+    mp4;
+    mp4_buffer_size     1m;
+    mp4_max_buffer_size 5m;
+}
+

Directives

syntax: + mp4
default: + none
context: + location

+Turns on module processing in a surrounding location. +

syntax: + mp4_buffer_size size
default: + mp4_buffer_size 512K
context: + http, server, location

+Sets the initial size of a memory buffer used to process MP4 files. +

syntax: + mp4_max_buffer_size size
default: + mp4_max_buffer_size 10M
context: + http, server, location

+During metadata processing, a larger buffer may become necessary. +Its size cannot exceed the specified size, +or else nginx will return the server error +500 (Internal Server Error), +and log the following: +

+"/some/movie/file.mp4" mp4 moov atom is too large:
+12583268, you may want to increase mp4_max_buffer_size
+