Search results matching tag 'Bitrate throttling'

Re: Bitrate throttling model should use Content Type Header

vsood — Fri, 25 Jul 2008 15:55:15 GMT

Hi Shiv

In addition what we also have is a server variable. If you want to change the throttling rate programmatically you could use server variables (details - refer section "Throttling with Server Variables").

Also Scott Hanselman blogged about how to do this here.

And as Jack mentioned you could add rules based on MIME types but those will have to data rules (i.e., fixed bit rate and you cannot use percentages). This would work great if you have most of the videos at a fixed bit-rate on your site.

Thanks
Vishal

Bitrate throttling model should use Content Type Header

skumar2003 — Fri, 25 Jul 2008 02:30:29 GMT

All of the documentation on the bitrate throttling model uses the term MIME type. But in fact the module only responds when a url has a certain file extension (*.wmv, *.mov etc.)

This design foraces us to have to implement our own handlers/module and the logic for throttling is media files are issued using dynamic urls such as a url to an aspx/ashx page.

Now when responding with media files we do set the content type header. If the bitrate module actually looked at this header and applied its rules to these responses we wouldn't have to do it ourselves.

In the real world, I've never designed a system that produced a url such that links or users had direct access to media files. These file are frequently stored elsewhere and are not under the application root folder, and so throttling using a file extension in the url makes no sense in the real world.

I'd love to see the bitrate throttling model respond to the content type header instead of the file extension in the url.

Bitrate throttling and out of memory issues

skumar2003 — Thu, 24 Jul 2008 04:01:50 GMT

This could be a bit complicated to explain and understand so I'll try my best to explain the set up.

Our media files (videos) are Flash video (.flv) files. These files are not directly accessible as a url that end with a .flv. As a result the bit rate throttling module does not intercept requests for these files automatically.

We had been using an IHttpHandler to serve these files because we authenticate the request coming from our site and from our video player before we issue the bytes. We read 8k chunks and write them directly to the OutputStream. This was working just fine, even for large files.

We then modified the handlers to incorporate the Bitrate throttling logic. The implementation works as expect, in terms of the burst and then throttling. However there is one thing I don't like about the we the bitrate throttling has been implemented and then there is an issue we're having to do with "Out Of Memory".

The one thing I don't like is that the http headers now include the bit rate information. These headers are visible across the internet and at the client. I don't believe there is any reason for this to be the case. I mean what's happening on the server end should remain at the server end (What happens in Vegas, stays in Vegas).

The bigger issue is that now the server is running out of memory each time we serve large files. This was not the case when there was no bitrate throttling in place. So it looks like IIS is buffering the bytes the handler issues (in a tight loop wirting 8K chuncks) because it is throttling the serving of these bytes. So if we're issuing a large file 800MB, the process is accumulating the bytes and eventually the process is out of memory.

The server has 8GB of memory and and at any time about 4GB is used (it kind of stays at this level) but we still see out of memory issues now.

My question is if IIS were to handling issuing the files itself, would this problem dissapear? Second, given the situation I mention at the start, is there a way we can still get IIS to issue the media files directly, *after* we authenticate the request? Also users should not be able to request these files directly using a url that ends with a .flv, we'd still like to intercept these requests and authenticate before allowing the files to be served.

I'm going to be trying an IHTTPModule that will intercept these requests and authenticate if the request is for our media files and allow or disallow. Does that sound ok?

The main issue (out of memory), is that "as designed"?