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flashvideoflvflvplaybackstreaming-flv-video

Flash Video FPS - Playing too fast in certain browsers

I'm playing a series of flv's in a web site. Over the past week or so they suddenly started playing at a faster rate than before. The site has been running for around 2 years with no problems and all of a sudden last week this has started happening in different scenarios.

After trying to work out the reason I've not been able to find an answer. Here are some of the tests I've performed to find a solution:

  • Fast playback occurs in Firefox, Chrome (Canary), and Safari on Macbook (Flash Player 17) - playback normal in Chrome.
  • Fast playback occurs in Firefox and Safari on iMac (Flash Player 17) playback normal in Chrome.
  • No Fast playback on Windows 8 (All browsers) (Flash Player 17)
  • Videos are from a web cam recording at 12fps & 9fps are speeding up however Videos from mobiles at 24 fps are fine
  • I'm not using net streaming, simply embedding a FLVPlayback and attaching the flv from the server
  • I've tried changing the frame rate of the swf to match but no fix.
  • When playing videos back within Flash itself they play fine so the videos themselves are not speeding up.
  • The web cam videos are recorded using Red5 using either 9fps or 12fps frame rates depending on users connection speed

Has anyone had a similar problem or does anyone know if Adobe's Flash player has changed in recent releases? Could this be my server (Ubuntu on AWS).

I always assumed flv videos play at their native speed, can I set the frame rate using Net Streaming rather than linking to FLVPlayback?

Why Mac not PC and on webkit browsers? Do they behave differently with multimedia?

Any help would be appreciated.

Thanks,

P

Solution

  • We have noticed this problem also. The issue is a mix of very specific points:

    1. have Flash 17.0.0.169 installed
    2. playback a FLV file with audio encoded with Nellymoser
    3. audio speed is set to 44100 Hz exactly

    If you have all these settings, video playback is twice as fast as normal.

    The solutions so far:

    1. Uninstall Flash 17.0.0.169 and install an older version (like 17.0.0.134) or the new Flash 18 beta (install at your risk, but note that it works perfectly)

    2. If you are recording your own FLV files with some Flash app and FMS/AMS, make sure to set the microphone rate to a lower value than 44kHz (like 22 or 11). Flex code like:

      microphone.rate = 22;

    Make sure to up-vote the bug 3976440 on Adobe's site so that they can apply the appropriate fix on current Flash version.