Movies encoded with HAP DS codec won't play back in palindromic loop.

  • With the end of QT32 support in Adobe video products I have been encoding movies for Isadora using the HAP DirectShow (AVI) codec. Just discovered that these files don't loop palindromically in Isadora, while the same files encoded with HAP Quicktime will.
    Is this an issue with DS playback? The HAP DS codec? The AVI wrapper? Or an Isadora bug?

    If anyone can replicate I'll file proper bug report.


    Mark not that Mark

  • Tech Staff


    Hap avi currently does not provide the same playback features as Quicktime Mov.
    You will find that scrubbing is also not as smooth as in Quicktime.
    If a solution is found it will be implemented.
    It does off load decompression to the GPU, freeing the CPU, which provides the best performance and playback on Windows.

  • Normal loop worked well for me though...maybe make another version of the export that has the forwards and backwards loops baked....shitty solution but not too hard.

  • @fred @DusX 

    Thanks, both.

    Ryan, that's good to know that limitation - I'm sure you guys are on the solution for Isadora V3. Good to know the CPU/GPU advantage. So I should continue to use HAP AVI whenever possible as the best playback solution?
    I can use Fred's workaround for the looping, or encode in HAP QT for things which I know will loop palindromically.


    Mark in London

  • @dusx

    I just saw your new Knowledge Base article on HAP. Excellent, thank you.

    Some things you could to add to that:

    With the NAB Spring 2018 release of Adobe Creative Cloud projects there is no longer support for the QT HAP.
    HAP Direct Show (.avi) codec works fine in all Adobe CC products that render via Media Encoder and therefore includes Premiere (CC2018.1 aka 12.1) as well as After Effects. However, only works with 'standard' frame sizes (so eg my projectors are native 1400x1050 4:3, the HAP QT will encode to that but the HAP DS AVI will not, I have to use 1024 x 768 and scale in Isadora).

    Also you can add the palindromic issue so that others don't lose time trying to figure out what the heck is going on :-)


    Mark  M

  • @mark_m Actually what I means was to create the forwards backwards loop as an AVI, instead of needing palindrome. You can then use a normal loop mode and stay away from quicktime.

  • @fred

    Yes, that's exactly what I'll do, thank you!

  • Tech Staff


    I have updated the article as you suggested. Thanks.