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GrevePoliti
Participant
July 10, 2009
Question

Dynamic Streaming - problems with MP4 (h.264)

  • July 10, 2009
  • 3 replies
  • 1165 views

Hey Flash Guru's

Im wondering if anyone have had any similar problems with the MP4 (H.264) format when implementing Dynamic Streaming using a FMS server?

Basicly we developed a player that detects the users bandwidth and plays the appropiate VOD stream (500, 1000 or 1500 kb/sec). Its tested with NetLimiter and works perfectly switching bitrates/files during the movie with both MP4 (h.264) and FLV (On2Vp6).

The problem occurs when you seek (jumps in the progressbar). When playing the MP4 files the player often uses 2-10 seconds to start the stream again. But when using FLV files the seeking is seamless and starts the stream within 2 seconds everytime.

So my question is if the FMS servers, Flash or the Dynamic Streaming got an issue with MP4 files?

Any help would be appreciated.


Best regards

Bo

Denmark

    This topic has been closed for replies.

    3 replies

    Asa_-_FMS
    Adobe Employee
    Asa_-_FMS
    Adobe Employee
    July 10, 2009

    H264 content does take quite a few images to get rolling before playback starts.  That's normal but it shouldn't take 10 seconds - it sounds like your buffer length might be overly long and it's taking a while to fill up after the seek.  Consider keeping a short buffer like as small as 0.1 seconds for playback starts.  Once you get your Play.Start or your Buffer.Full message then you can adjust the buffer length on the fly to something longer to handle the bumps.

    It's also possible that you're getting the high bandwidth stream again when you seek by mistake.  Check your server logs to see that you're getting the play that you're expecting there.

    Asa

    FMS

    T
    techeye
    Participating Frequently
    July 10, 2009

    I think this is a current limitation of h264 playback that is being worked on.  It has to do with the bitrate of the file, the amount of keyframes/iframes, and when a "full buffer" can be rendered.  There might be a bug already filed on this... I am not sure though.

    Anyone with a work around please post it!

    miquael
    miquael
    Inspiring
    July 10, 2009

    I am having a similar problem with MP4.  I do not know the exact answer or solution yet.

    I will let you know if I do.  Please do the same.  I'm on deadline! 

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