How to troubleshoot streaming video (rtmp) performance?

开发者_C百科I'm streaming videos via rtmp from Amazon Cloudfront. Videos are taking a loooong time to start playing, and I don't have any way of figuring out why. Normally I'd use the "Net" panel in Firebug or Web Inspector to get a good first impression of when an asset starts to load and how long it takes to be sent (which can indicate whether the problem is on the server end or network versus the browser rendering). But since the video is played within a Flash player (Flowplayer in this case), it's not possible to glean any info about the status of the stream. Also since it's served from Amazon Cloudfront, I can't put any kind of debugging or measuring tools on the server (if such a tool even exists).

So... my question is: what are some ways I can go about investigating this problem? I'm hoping there would be some settings I can tweak on either the front-end (flowplayer) or back-end (Cloudfront), but without being able to measure anything or even understand where the problem is, I'm at a loss as to what those could be.

Any ideas for how to troubleshoot streaming video performance?

You can use WireShark (can diessect RTMP) or Fiddler to check what is going on... another point (besides the client and the server) to keep in mind is your ISP.

To dig deeper you can use this http://rtmpdump.mplayerhq.hu/ OR http://www.fluorinefx.com/ OR http://www.broccoliproducts.com/softnotebook/rtmpclient/rtmpclient.php.

You need to keep in mind that RTMP isn't ideal since it usually bypasses proxies and tries to make direct connection... if this doesn't work it can fallback, but that means that some time has already passed (it wait for a connection timeout etc.)... if you have an option to set CloudFront/Flowplayer to RTMPT then I would recommend doing so since that uses Port 80 for the connection.

Presumably - if you go and attempt to view a video - then come back 20min later and hit it again - it loads quickly?

SAN -> Edge Servers ---> Client

This is all well and good in a specific use case (i.e. small filesize of the origin content, large long running cache) - but, it becomes an issue when it's scaled out, with lots of media hosts running content through the system i.e. CloudFront.

The media cache they keep on their edge servers gets dumped fairly often - after the cache is filled - start dumping from the oldest file in cache - so if you have large video files that are not viewed often - they won't be sitting in the edge server cache, and take a long time to transfer to the edges - thus, giving an utterly horrific end user experience.

The same is true of youtube, for example - go and watch some randomly obscure, high duration video - and try it through a couple of proxies, so you hit different edge servers, you'll see exactly the same thing occur.

I noticed a very noticable lag when streaming RMTP from cloudfront. I found that switching to straight http progressive from the amazon S3 bucket made the lag time go away.