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Thread: Smooth Streaming with ismv files

  1. #1
    Join Date
    Dec 2011
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    28

    Default Smooth Streaming with ismv files

    Hi,

    We use Microsoft Expression Encoder 4 Pro to encrypt content with PlayReady DRM.
    And we put ismv files on the wowza server to play.

    Sometimes player cannot play because it cannot download the manifest file.
    Then we found the response time is too long to download manifest file.
    It may take 7~8 minutes to get manifest file, but player has already been timeout.

    When player works properly, it only takes 2~6 seconds to get manifest file.

    Is there any way to improve it?

    Thanks,
    Roy

  2. #2

    Default

    Can you provide media and steps to reproduce the problem?

  3. #3
    Join Date
    Dec 2011
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    Default

    Hi,

    We did more test and found some new information.

    1. Put the ismv file in local storage
    It almost takes 2~8 seconds to download manifest (depends on file size).
    When client starts to download manifest, the CPU usage of wowza process will rise to 100%. (by Linux top command)

    2. Put the ismv file in remote storage (NFS)
    It sometimes takes 5~8 minutes to download manifest.
    When client starts to download manifest, the CPU usage does not rise immediately.
    After 5~8 minutes, CPU usage start to rise.
    Then wait more 2~8 seconds, client will receive manifest.

    It seems like wowza server needs to scan the ismv file before it generates manifest.
    And this action will cause more CPU usage and respone time.

    But wowza server does not scan file immediately when we put the file in NFS.
    This is a problem we cannot figure out.

    The media files as follow

    test1.ismv (2.8G)
    test2.ismv (212MB)

    The manifest response time is

    test1.ismv => local : 8 sec remote: 431 sec
    test2.ismv => local : 2 sec remote: 48 sec

    I am sorry the files are too large, but the small files hardly reproduce problem.
    These files cannot play since DRM protection, but you can try to get manifest.


    Thanks,
    Roy
    Last edited by Roy0817; 08-10-2012 at 02:33 AM.

  4. #4
    Join Date
    Dec 2007
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    Default

    Roy,

    It sounds like the ismv files you are encoding are fragmented. You are probably using Expression 4 Encoder and taking the "Silverlight Project" path. Select "Transcoding Project" instead to encode to unfragmented mp4 container. Take a look at the Expression 4 presets in this article as a staring place:

    http://www.wowza.com/forums/content....demand-content

    The resultant files will play in Silverlight for smooth streaming, and you won't see that CPU spike.

    Richard

  5. #5
    Join Date
    Dec 2011
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    Default

    Hi, Richard

    We use wowza sample presets to encode, and the output files are MP4.
    But it cannot select DRM options to encode, the error message is
    "DRM is not supported for the current encode settings. It is only supported for IIS Smooth Streaming."

    It seems like Expression Encoder cannot output MP4 file with DRM protection, it only supports ismv output files.

    Is there any other suggestion for us?
    Can you provide other sample presets to encode MP4 file with playready DRM?

    Thanks,
    Roy
    Last edited by Roy0817; 08-13-2012 at 01:48 AM.

  6. #6
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    Default

    DRM is in the Security Tab, under Job Output in the panel. It is enabled with Output Format set to "MP4"

    Richard

  7. #7
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    Dec 2011
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    Default

    Hi, Richard

    Yes, the DRM options can be enabled with output format set to MP4.
    But when you press encode button, it pops up error message as I mentioned.

    Screen capture of expression setting
    setting1
    setting2
    fail encode preset

    Thanks,
    Roy
    Last edited by Roy0817; 08-14-2012 at 12:47 AM.

  8. #8
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    Default

    Right, hmm. I will ask around about it, see what I can find out, but evidently ismv files are required to do what DRM has to do. I will check.

    Richard

  9. #9
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    We talked about this. I don't have an alternative to using ismv files, but they are fragmented which adds significant overhead to Wowza, and encryption increase overhead further. So you have to take this into account, you need a lot late model quad or dual quad cpu and lot of ram, and of course well tuned.

    You might get some benefit from defragmenting the files with mp4box, however we don't know if encryption will work after de-fragmenting.

    Richard

  10. #10
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    Dec 2011
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    Default

    Hi, Richard

    OK.
    Now I see the ismv files will increase wowza overhead.

    The another problem is why the response time is too long when ismv file put in NFS. (the problem in #3)
    If we put ismv file in local, it only causes long loading time when play video.
    But if we put in NFS, the player cannot play video since response time is too long.
    It seems like wowza will be slow start to scan ismv files in NFS.
    Is this also a ismv files problem or something else wrong?

    Thanks,
    Roy

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