From inspiration to realization » Flash media server

flash media server security hardening

Avi Tzurel — Sun, 25 Jul 2010 12:51:43 +0000

today, while browsing my feed in google reader, I found something very interesting.
this link is a hardening guide for flash media server.

for quite some time now I have been developing and consulting on flash media server advanced topics, I have been teaching students and consulting companies on issues regarding this great peace of software.

Adobe seemed vert silent about this product for some time, not publishing any new materials what so ever, so it was very nice to see this link, I read it and it has some good observations and very well written instructions on how to harden your server.

Dynamic streaming (Adaptive bitrate) using Flash media Server

Avi Tzurel — Thu, 15 Apr 2010 18:56:09 +0000

Video and the web are long time friends already, you see lots of websites with some sot of player for video content, you also see media companies and television channels serving video over the wire to the end users.

Video can be downloaded (progressive download) to the client like YouTube or can be streamed to him.

I won’t discuss the pro’s & con’s of streaming and progressive, we will only be discussing streaming in this post.

So, What is the post worthy problem we have when streaming video to the client?

Continue reading and find out.
When streaming video, you usually encode your video in a certain bitrate, this bitrate will work well in certain computers and won’t work well in others.

Why is that?

That’s because each of your users has a different connection thus being capable to receive a limited amount of bytes streamed to him.

So, you always have to find the “sweet spot” where you deliver a video that looks good and also light enough to fit a wider range of network connection speeds.

That is of course a problem becuase sometimes you want to stream hiQuality video and audio (HD) and you can’t because some of your users won’t be able to watch it smoothly.

Well, this is a problem we will solve here in this post.

Flash media server introduced a new way of streaming video to the client, it is called dynamic streaming and it is very dynamic (name implies just that).

That way, you can create several encodes to the same source movie and supply a movie best fit to the user cosuming it.

Another obvious advantage of this approach is the way it skips on top of the movie, when you skip to a further point in the movie, you are actually being supplied a different movie from the lowest quality to the highest.

So, how is it done, first, let’s create a flash file (I’m using flash CS4).

Now, we will create (by dragging and dropping from the components panel) an FLVPlayback control.

We will give it the same dimensions as the movie itself so it will fill the entire surface.

Now, we will give the player an instance name of “flvPlayer”

so, we have a movie, we have an FLVPlayback control, we called it “flvPlayer”.

We will create another layer, called “action script” and we will create this code inside.

import fl.video.*;
VideoPlayer.iNCManagerClass = NCManagerDynamicStream;
flvPlayer.source = "dynamicStream.smil";

OK, so as we can see we created a pointer to a file called “dynamicStream.smil”, this is a special file (XML format).

This file details the following

FMS Url
files you have encoded and a network speed in correlation

The file looks like this:

Now, when we put this file on our web-server, the user will get the file it can receive and play, not slower, not faster, just the perfect file for him.

NO buffering, NO waiting, NO frustration, smooth, cool and fast user experience.

Good luck.

You can download the complete solution from here:
Source - Dynamic streaming (flash media server) (112)

Flash media server statistics using sawMill

Avi Tzurel — Sun, 14 Mar 2010 06:40:50 +0000

I have been using Flash Media Server for a while now, at least 3 years, I implemented solutions on top of this amazing products for clients in wide ranges like Start-Up companies, E-Learning systems and more.

Flash media server has some disadvantages, one of those is definitely the lack of normal statistics. The terminal will give you the real time data but if you want to drill down into last month and 3 month ago or more, you won’t be able to get any data in a comfortable and nice view.

I found a product called SawMill, this product is unobtrusive on your flash media server, you don’t even have to install it on your server.

So, how can you get Stats you ask?

Well, you simply install the product, you give it a path to your log files and it will do the rest, it has a built in support for the Flash Media Server log format so you don’t have to “teach” it how to read the logs or do any kind of configuration.

You have stats like:

Client Ip’s
Media files played
amount of data streamed
time of use
pressure hours

and many more of course, the real treat is that you can drill down from year to month to day to hourly stats.

Those can come in handy if you want to learn more about your website and the usage.

Example of what a stat sheet looks like:

RTMP being blocked by firewalls – Flash media server

Avi Tzurel — Fri, 19 Feb 2010 17:34:27 +0000

If you ever worked with Flash media server or any other media server for that matter you probably know they are not working with the regular Internet protocol which is HTTP, all of the media servers (almost all at least) are working on top of a protocol called RTMP.

Now, if you have users working behind a firewall, they probably can’t get passed it’s restrictions and they will (in most cases) be blocked and unable to see your application / video.

If you are working on a server like WebOrb (I’m working with it) then the data will also be blocked, and that is a bug issue

Here’s a way to solve this

Well, let’s first talk a bit more about RTMP, before ditching it and moving on.

With flash media server you can use RTMP over a few ports (1935, 80), 1935 will probably always be blocked because it is not a known port and even simple routers often block it.

port 80 makes things a bit more complicated, you have to make FMS listen to a specific IP or your web-server (if on the same server) will not work.

So, first rule is always use port 80, this is one way to make more users be able to connect to your application, watch your videos and interact with your service.

The connection is being made like so:

rtmp://your_ip_address:80/app_name

DO NOT use any type of arrays of ports, simply use port 80, if the client can’t connect to RTMP on port 80, he will no be able to connect on RTMP no matter the port you are using.

So, What am I actually saying over here…?

I’m saying you should only make 1 connection attemp, this attempt is on port 80 using RTMP, this should be your first choice, if the connection is unsuccesful, you should move the connection to use RTMPT which is RTMP encapsulated over HTTP, firewalls will not block this connection becuase it makes RTMP “hide” behind HTTP traffic on port 80.

The connection is made practically the same way

rtmpt://your_ip_address:80/app_name

Why not use RTMPT at all times?

You should not use RTMPT at all times because there’s a performance issue, there is an overhead on top of each packet sent.

Why not go through all the possible ports with RTMP first, Why only 80?

In most cases, firewalls will block every port (but 80), the timeouts the user will have to go through will be very long before he will finally be redirected to RTMPT.

I will post some code on how to fallback more efficiently later on this week, this post was actually inspired from a client’s solution I did this week during a consulting session.

Good luck