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The dreaded black flash between movies



  • Hi all,

    I am having a problem.  I am attempting to playback 720p PAL Pro Res Proxy files using the new GPU Movie player and Projector (2.0.5).
    I am getting good frame rates, sometimes a stutter here of there at the very beginning of the file, but an acceptable amount.

    The problem is when jumping from one movie to the next, either by jumping by one scene to the next, or by changing the movies in the player itself:
    sometimes there is a black flash between my two scenes (or movies), sometimes not.
    Unfortunately my video is on a white background....

    Same problem occurs on a macmini from last year running 10.10 (I think)  and using AV Foundation as a playback engine.

    Has anybody encountered this problem?  If so, any solutions?

    I'm using an old Macbookpro (2008) and 10.6.8 and a fast SSD with an Esata connection(see my signature line for more details).

    Thanks for any help.

    ur,ummmmm.............................eric



  • So, when I switch the videos in the movie player, I sometimes see the "stage" Actor input field flash from" n/a" to "1" and the label "stage" turns from grey to white for an instant.  At that moment I get the black "flash".

    Hmmmm.

    ur,ummmmm.............................eric



  • Every time when I see PAL mentioned I feel that there is something not quit right with the movie codec. I would try ProRes422. I do not see any problems with the same old MBP even pulling movies from SSD connected to internal PATA bus.


  • Tech Staff

    Have a read through this: 

    http://troikatronix.com/support/kb/optimizing-for-speed/


  • @vanakaru, by PAL I mean 25 fps.  The codec is ProRes Proxy. 422 is slower on my machine.

    @Skulpture, thanks but I have read those guidelines many times.  I think I'm doing everything I can to optimize.


  • Tech Staff

    Ok - I thought you would have, I just always ask the obvious first, because; well you never know!

    Even us mods/beta testers have to check the knowledge base now and again. 


  • @Skulpture.  Sorry, I didn't mean to be short.  This is a great resource!  BTW.  the optimize for speed post is out of date (it does not recommend H264 for encoding, but Isadora 2.0.5 seems to like H264 if one is using AV foundation for playback; I am not as I am still using OS 10.6.8).


  • Tech Staff

    Hey @ursullivision  no, no it didn't read as being short. It's all cool.  

    The only thing I can suggest is opening an ticket and getting the super clever dudes (DusX and Jamie) to check it out for you - maybe you can send them the movie and have a look into it for you.


  • I see you only have 2GB of RAM from your computer description in your Sig line.

    After the OS loads and Izzy that doesn't leave much left so I wonder if these flashes are to do with memory starvation? Does the MacBook Pro have a discreet GPU if not it's using system memory and the cliches causes by a clash on the bus.
    I'm just guessing as I haven't come across these flashes with Izzy. AV Foundation does give me juddery playback on my Mac Pro test machine so I tend to use QT playback. On my MBP that I use for development it doesn't matter what I use.


  • @Unfenswinger  Hmmm, My machine does have a discreet GPU.  it could be RAM.   But that wouldn't explain why it had the same problem on the MacMini (4 gigs ram).  Also, this short "activation" of stage 1 is weird.

    @Skulpture.  I guess I'll try that.  Thanks.



  • @ursullivision

    From personal experience one izzy project would regularly crash my Mac Pro but is stable as anything on my new MBP. The crashes seemed to be due to the timing of scene changes so there may be some timing issue within the project causing the flash frames. Since I moved my license over to my MBP there were no crashes running the project at all so I never followed things up.

  • Tech Staff

    @ursullivision

    Your observation about the stage settings changing momentarily in the actor, makes me think it might be due to a recently identified and fixed bug.
    Unfortunately, we are still testing.. and its not ready for release. Of course I can't say for sure, so I can only suggest using a work around for now (use 2 players maybe?.. different layers? .... preload?)
    I will say that the next release is worth the wait! Awesome new features!


  • @DusX, OK.  I guess this show will just have a few black flashes.  It's too close the performance date to fiddle too much.

    Thanks for the info.

    ur, ummmmm..........................eric


  • Tech Staff

    Sorry, I could be of more help.


  • Tech Staff

    Could you maybe post one of the videos here for us to try? Even just a 10second loop?



  • @Skulpture, Sorry it took me so long to get back to you. Lotsa work. The show went well despite the "dropouts". How (where) can I upload the file for you?
    5d38d9-p1030901.jpg


  • Tech Staff

    Do you have a dropbox or similar?



  • Yes, I can upload to Dropbox.  I'll email you a link if that is ok.


  • Tech Staff

    Sure. Let me know when its up.



  • DB link sent to your email address at gmail.


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