5 Replies Latest reply on Jan 29, 2010 11:15 AM by waterdad568

    RTMP/FMS & Flash Video Audio Echoing?


      Our client has encountered a bizarre problem where they hear an audio feedback or some sort of "duality" when playing an F4V file through FMS. When I tested this myself, I did not encounter this issue. I'm wondering if anyone here can provide some insight as to some of the potential causes of this issue and how we can fix it.


      We are using

      1) FLVPlayback

      2) Application targets the Flash 10.0 runtime

      3) We are using a standard FMS 3.5 install, videos located in the vod folder

      4) Trying to playback F4V files. The samples provided by FMS also exhibit the same issue.


      On another note, I built a bare-bones Flex application (SDK version and using the VideoDisplay component and it always has the duality problem. It even gets worse as I refresh the page, the echoing / multiple audio playbacks seem to compound.


      Thanks for any assistance you can provide.

        • 1. Re: RTMP/FMS & Flash Video Audio Echoing?
          waterdad568 Level 3

          Does the sound play properly the first time? If you clear all caches and then load fresh does it play properly? Have you played the F4V's independently on any other app... Nero, or... and do they play similarly? If the F4V's run well out of the app, then my best guess would be to look at the sound code trail in the app, find the sound instance where it is first run, and see if that instance of the sound is stopped or removed anywhere, if it isn't, it may just be loading a new instance each time the code is run.


          Somewhere to look anyway.

          • 2. Re: RTMP/FMS & Flash Video Audio Echoing?
            TheNuttyNut Level 1

            It does happen every time I start playback. The FLVPlayback also uses NetStream as the underlying mechanism to retrieve video, but from video examples I've seen with that class there's no way to cause the audio to loopback like I've experienced. I'm curious, how would one do such an effect with the NetStream class (or perhaps with the flash.media.Video class)? Is it possible to get it to play an audio stream multiple times? Or any of the video controls, how would one go about causing something like this? If I know how to produce it, then perhaps I'll have a better chance at finding the culprit.

            • 3. Re: RTMP/FMS & Flash Video Audio Echoing?
              waterdad568 Level 3

              I'm not sure if you can loop or play the same content in the same component, but you certainly can run multilple instances of a component running the same content. Back to looking to see if they are being called more than once somewhere.


              I'm not sure how a player would be able to echo a sound without having multiple instances playing milliseconds apart. Unless the player is corrupt.


              Have you tested the app/swfs on different players/machines, the F4V's independently, is there a way you can use another known working app to test the netstream links. Import the classes from this project into a known working one to test the classes, or replace them with a known good copy. Trace each function that you can. Break it apart and test each segment/component/content if possible, process of elimination will eventually show you exactly where you need to look.

              • 4. Re: RTMP/FMS & Flash Video Audio Echoing?
                TheNuttyNut Level 1

                It appears the problem lay in the fact that multple NetStream play() requests were sent out to the server. The FLVPlayback component didn't keep track of its NetStream actions and loosly allowed multiple play requests to be sent out. Rather than the additional play command resetting the stream (which I've seen do on internal tests), on some instances this caused multiple streams to be piped through the network. This was the source of the multi audio playback (and probably an additional video feed as well). I fixed the issue by enforcing rules to only call the NetStream play method once. It wasn't a straight forward fix unfortunately, since the video resizing logic also had to be adjusted as well (hard to believe someone could make such logic so complicated). Should anyone run into a similar issue like this, hopefully this will guide them on to the right path. Check the FMS server logs and make sure you only see one connect and one play command.


                Thanks for your asistance on the matter waterdad. It was a long and tediuous exercise for me, but I'm happy to move on

                • 5. Re: RTMP/FMS & Flash Video Audio Echoing?
                  waterdad568 Level 3

                  No problem, help was given to me when I asked, just trying to pay it forward and help if I can.