Discrepancies on playback depending on machine?!

edited March 2017 in Pro Support

Audio in rendered mp4 plays a microsecond behind on one machine, accurately on another, and ahead by a smidge on still another. Husband is giving me fits about it. He's a guitarist, and he's very, very particular about audio being absolutely in sync. It plays accurately in Hitfilm, and on three of my computers, one running WinPro7, one running Vista, one running Win10. But when he plays the files on his his 8.1 or his Win10, it's just a smidge slow (We're talking unnoticeable to me, but he demonstrated it visually by analog recording it with a cam.) and a smidge fast on his WinPro7. On the other Win7 Home Premium machine and on his old XP machine, it plays accurately to his ear, as does it via his Smartphone. Any ideas?

MORE: Just told husband I posted the query, and he said to mention that in Windows Media player, if you start and stop the video, it gets out of sync...which, I believe is a Win Media Player problem, not the Hitfilm rendered mp4. If he brings up an old Quicktime player, it plays accurately.  I also measured the discrepancy and we're talking less than one frame at 30fps.

Is there any way to ensure that, no matter who is playing the files using whatever machine and OS and player, that they get an accurate video synced to audio?


  • Triem23Triem23 Moderator

    First things first. 

    Welcome back, Dawn, glad to hear you and hubby are now recovered enough from the accident to be nitpicking >1/30th synch issues. You're obviously both better.  :-) 

    My first instinct is that if the desynch is happening with player A,  not player B the issues are at the player's end(s). 

    Out of curiosity, maybe download someone else's live performance video and see if the synch issue is happening with non-hitfilm output? 

  • Hi, @Triem23 . Thanks for the well-wishes. The latest disaster here was flooding beyond anything I've seen on this place ever. It was absolutely scary.

    As to the issue he's experiencing, we've narrowed it down to Quicktime plays it accurately but late versions of Windows Media Player doesn't. It will lose sync by about 1 frame, more if you pause the video, then play on from the pause.  (And I say 'about' because I don't know if my screen capture cams are accurately reflecting the frames as they are in the Hitfilm master file.)

    But there's another problem that's bigger I discover:

    The template for the video is the audio master file...which is backwards to how I do my book trailers.  Creating a video where the audio is the master template, I can't get the video takes (done to a click-track, too) to match to my husband's satisfaction because the piece's musical phrasing sometimes ends and begins somewhere that's actually mid-frame, it seems. Having him watch the process in Hitfilm, he'll say to me that he wants it to start, not at the previous frame, but between this frame and that frame.  And, yes, he's that picky about it.

  • edited March 2017

    He's more sensitized to the issue, whereas 99% of people have  much higher tolerance, so won't even be aware of the issues he notices.

    This makes interesting reading. http://lipfix.com/technical_details.html

    Once you've become aware of it, it's harder to become unaware of it.

    So, play him this video, it'll help desensitize him again.


    Sorry, I meant the title might help... :)

  • That article is amazing, @Palacono ! Absolutely explains what is happening and why. Holy wow. Now, if I can just get my husband to read it and comprehend! That helps me with my stress levels, though. If it's something beyond my control, then I'm in the clear for culpability.

  • Triem23Triem23 Moderator

    I haven't read what Palacono shared, but it's probably a "hey, video has limited resolution" article. 

    Now... One way to TRY to get closer is to up the project resolution. Maybe to 60fps?

    Just remember a 60fps project should be set first, then output would need to happen at 60fps as well. Too late for anything already done, but a note for the future. 

    It's actually something I discuss with singers at my karaoke gigs. 'Words don't match music.' 'Yeah, video is 30fps. If the music ain't a multiple of 30 bpm it won't synch exactly.'

    Sorry about the flooding. Rough winter. 

  • edited March 2017

    I'm starting over, yet again, @Triem23 . I've worn out that spot in my brain and a fresh canvas is the only way for me to not blow some gasket in my brain.  I thought about upping the fps to 60, but worried that doing it at 60fps with videos that are taken at 30fps will absolutely muck things up. Am I worried over nothing and should try that? The piece runs at a PRECISE (as in we play to a click-track precise) 120 beats per minute. But the issue comes AFTER the " , a musical symbol indicating a break between sections. There are two of those in this piece, and, after each, everything winds up just a whisker's breadth 'out'. I don't dare cut the audio master file. He'll notice.

  • Triem23Triem23 Moderator

    Hitfilm will try to conform the 30 fps video to 60. This means either frame doubling or blending, so it's not perfect, but at least you can have a little bit of leeway by cutting on a "half frame" (I'm assuming you recorded at 30).

    The main thing is to export at the same fps as the project settings. 

    I'd personally try trimming the master audio. Did that on one of my (former) band's tracks. Only one to know was the guitarist, because he was there when I made the cut. Bassist and drummer never noticed... 

  • Thanks, @Triem23 . I'll try it. If it works, I'll be miles ahead. I was supposed to have this new version done yesterday for him to check out, and he's calling, calling, calling...about it.

  • @Triem23 Nope, it was an article explaining why no one else but him will notice what he's worried about. ;) 

  • @Triem23 Okay. Going to 60fps is working. Thank you SOOOOOO much.

  • Triem23Triem23 Moderator

    Dawn. Yay! 

  • @Triem23 . A HUGE Yay! Thank you SOOOOO, SOOOOO much! I'm staying up all night to get the rough cut done so he can tell me where I effed up. :D But, at least losing sleep will mean that I'll be half done with this one and, maybe, just maybe, I can get back to coding out our relaunch of zentao.com!

  • Thanks to @Triem23 , @Palacono , and @Aladdin4d Because of their help and suggestions, I was able to get this done to my husband's thrilled satisfaction:

  • Happy for you getting it done, and ending on the cat's lack of interest was perfect. :D

  •  Very nice! 

  • edited March 2017

    Thanks, @Palacono and @Stargazer54 It's not as good as others can do, but at least I waddled my way through it enough that husband is happy.

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