6 Replies Latest reply on Apr 22, 2011 3:11 AM by daslicht

    osmf f4m, Cache ?

    daslicht Level 2



      When I playback a f4m File via HTTP Dynamic Streaming , are parts of the file remain in cache or are the just played back like when using a rtmp stream ?


      is the full file stored in the cache ?

        • 1. Re: osmf f4m, Cache ?
          daslicht Level 2


          • 2. Re: osmf f4m, Cache ?
            Andrian Cucu Adobe Employee



            I suppose that your question refers to browser cache. Browsers have different caching strategies. Some browsers will remove older cached content when they need space. You can end up with the whole video in browser cache if there is enough space for it.

            Also note that CDNs and some routers are also caching http streaming content with different kind of caching strategies.


            Does that answer your question?



            • 3. Re: osmf f4m, Cache ?
              daslicht Level 2


              thank you for your reply but this does not really answer my question.


              Basically there are two situations:



              when you play a RTMP stream from a Flash Media Server with a Flash based client, the steam packages are not cached at all,

              they are just played back and do not accumulate in RAM or Browser cache.



              if you play a shoutcast stream  while using the Flash Sound Object , the whole stream is progressively downloaded and played back.

              It fills up all RAM and crash the Flash Player (wide discussed as Flash Memory leak, and I tried it myself  to get sure )


              Now my question is how does the OSMF Framework handle Streams ?

              If I have a fragmented f4m are those fragments kept in ram after playback or are they go to nirvana as when using RTMP.


              Meanwhile I played around with OSMF streams and it seems that there is no memory issue at all. (subjective not scientific proven)




              • 4. Re: osmf f4m, Cache ?
                daslicht Level 2


                looks like the played packages are NOT released from memory, therefore each computer with a low amount of memory will crash when streaming a live event for several hours:




                • 5. Re: osmf f4m, Cache ?
                  Will Law Level 1

                  I think f4f fragments are cleaned up quite nicely. Here is a stream that is 1045hrs long and growing that you can test against. Drag it to live after it starts:


                  http://osmf.org/dev/1.5gm/debug.html?src=http://zerilivehdndemo-f.akamaihd.net/z/demotest_ 1@49207/manifest.f4m


                  There is a memory display in the debug panel. After an hour, (FF, Win7) it has not climbed. It oscillates 3-5Mb but that is all.





                  1 person found this helpful
                  • 6. Re: osmf f4m, Cache ?
                    daslicht Level 2

                    Basically I have created a "fake" live stream (aac only).

                    Once a client connects to the server, it acquires a continuously incrementing start point variable from the server.

                    Once the end is reached the server-side timer restarts again.

                    So I get a infinite loop.


                    After the Memory usage climbed up to 194MB (in windows task manager) Firefox 4 crashed.


                    I am trying it now with your suggested stream and firefox 4 and will report the result.


                    [EDIT 1]



                    after about 5 minutes I have a Memory usage of:

                    firefox memoryleak.JPG

                    after about 10 Minutes:


                    Your debug statistics behave like you stated in your post.


                    opera look better no obvious rise in 5 minutes playtime.

                    after 10 minutes 0.100 K rise


                    Now trying it on my macbookpro with safari, chrome, and firefox.

                    Which browsers did you tested it with ? FF4?


                    [EDIT 2]

                    Firefox cleaned up Memory after about 20 minuts:

                    firefox 3.JPG


                    Now its time to find out why it crashed with my solution :/