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flash media server taking forever to load large files

Jan 12, 2011 7:37 AM

We purchased FMIS and we are encoding large 15+ hour MP4 recordings using flash media encoder. When opening these large files for playback, which have not been opened recently  the player displays the loading indicator for up to 4 minutes! Once it has apparently been cached on the server it opens immediately from any browser even after clearing local browser cache. So a few questions for the experts

 

1. Why is it taking so long to load the file. Is it because the MP4 metadata is in the wrong format and the file is so huge? I read somewhere that Media Encoder records with incorrect MP4 metadata is that still the case?

 

2. Once its cached on the server, exactly how much of it is cached. Some of these files are larger than 500mb.

 

3. What fms settings do you suggest I change. FMIS is running on windows server R2 64 bit, but FMIS itself is 32 bit. We have not upgraded to the 64 bit version. We have 8GB of ram. Is it OK to set FMS cache to 3GB. And would that only have enough room for 3-4 large files, because we have hundreds of them.

 

best,

Tuviah

Lead programmer, solid state logic inc

 
Replies
  • Currently Being Moderated
    Jan 13, 2011 10:30 AM   in reply to tuvman1

    Hi Tuviah,

     

    You may want to email me offline about more questions here as it can get a little specific but I'll hit the general problems here.

     

    MP4 is a fine format, and I won't speak ill of it, but it does have weaknesses.  In FMS implementation those weaknesses tend to manifest around the combination of recording and very large files, so some of these things are a known issue.

     

    The problem is that MP4 recording is achieved through what's called MP4 fragmentation.  It's a part of the MP4 spec that not every vendor supports, but has a very particular purpose, namely the ability to continually grow an MP4 style file efficiently.  Without fragments one has the problem that a large file must be constantly rewritten as a whole for updating the MOOV box (index of files) - fragments allow simple appending.  In other words it's tricky to make mp4 recording scalable (like for a server ) and still have the basic MP4 format - so fragments.

     

    There's a tradeoff to this however, in that the index of the file is broken up over the whole file.  Also likely these large files are tucked away on a NAS for you or something similar.  Normal as you likely can't store all of them locally.  However that has the bad combo of needing to index the file (touching parts of the whole thing) and doing network reads to do it.  This is likely the cause of the long delay you're facing - here are some things you can do to help.

     

    1. Post process the F4V/MP4 files into non fragmented format - this may help significantly in load time, though it could still be considered slow it should increase in speed.  Cheap to try it out on a few files. (F4V and MP4 are the same thing for this purpose - so don't worry about the tool naming)

     

    http://www.adobe.com/products/flashmediaserver/tool_downloads/

     

    2. Alternatively this is why we created the raw: format.  For long recording mp4 is just unideal and raw format solves many of the problems involved in doing this kind of recording.  Check it out

     

    http://help.adobe.com/en_US/flashmediaserver/devguide/WSecdb3a64785bec 8751534fae12a16ad0277-8000.html

     

    3. You may also want to check out FMS HTTP Dynamic Streaming - it also solves this problem, along with others like content protection and DVR and it's our most recent offering in tech, so it has a lot of strengths the other areas don't.

     

    http://www.adobe.com/products/httpdynamicstreaming/

     

    Hope that helps,

    Asa

     
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