Sound syncing issue not covered in any forum

investigate

(Steve Robbins) #1

After 12 hours of work I saved it up with a view to tweaking the mistakes that were in there.
Beforehand I exported to MP4 and it took a long time. finally producing a video of 24 minutes on a 4+ minutes piece of audio
Opening it the next day the issue started. If I play a few seconds of the video and stop it then restart at that point the video tracks fine but the audio starts from a much earlier time.
I updated to the latest version and the issue is still there. I tried a clean project and the issue is on that one also. Any advice is appreciated

Vid audio MP3 320kbs 44.1khz
Vid frame rate 12 fps
PC quadcord AMD 3.6 ghz 12gb ram
Radeon graphics card (Cant remember what one) with 2gb ram
Win 7 X64 os


(Jose Moreno) #2

@steverobbins We’ve recently come into contact with an issue related to sound sync which has been fixed just a few days ago also another issue with sound volume was fixed several weeks ago for exported videos.

To test this you can try the latest development version of pencil2D and see if it eases your problem, however let me say up front that even with these fixes Pencil2D is still not recommended for heavy audio management. From a professional standpoint I recommend you to do only the video part in Pencil2D while using audio reference with the sound layers, but do the final sound work in a dedicated video editor for maximum accuracy.

The link to Jan 18th 2019 version for windows is on this link, please test it out and let us know if it helps: https://drive.google.com/open?id=1dgAZWUAzXM0afH7Gh1zU5g9BSI2Rjx6c


(Steve Robbins) #3

lol. That was my intention. I’m using Cakewalk for all the audio


(Steve Robbins) #4

Hmmmm. Hasn’t fixed the issue. Could it be the size of 3108 frames that’s the issue?


(Jose Moreno) #5

@steverobbins Ah, shucks well that’s unfortunate indeed, however if you’re willing to assist us into finding the issue at hand I can tag a developer so he can ask you some questions in order to ascertain the problem that’s troubling you. Of course this will take time so definitely finish your job with another sound / video editor for now.

Also, would you be okay with sharing your work files and the resulting video that has the issue? If you accept all of your files will not be shared to any third parties, only the Pencil2D team will have access to it and once the problem has been found and fixed we’ll delete the files. Other than that we hope that this can be solved soon as well.


(Steve Robbins) #6

Sure thing. I also tried it on a windows 8 machine and got the same issue. So it could be the file itself as opposed to the software


(Jose Moreno) #7

@steverobbins Alright, thanks a lot. I’m going to tag @scribblemaniac who has worked on fixing the sound issues recently so hopefully when he’s available he’ll be able to ask you more accurate questions to gather the necessary info in order to track down your particular issue.

As for uploading the files, if you want you can use a cloud storage software you trust and send us the link to that to info(at)pencil2d.org or you can PM me the link and i’ll make sure to pass it along the dev team.

Either way thank you for your patience and hopefully this can be solved soon enough. Cheers.


(scribblemaniac) #8

Sorry for the delay. This sounds kind of like the opposite of what other issues we’ve had lately. When you look at the red bar on the timeline, does your sound start to play right when it reaches your sound, either during the first play or after restarting at the same start point? When you export your project, does the sound start at the same time as the first time you played, the second time you played, or neither? The only thing I can think of is that there is a delay the first time you play the sound as it has to load the file from your disk. Sharing your file as @JoseMoreno may be a helpful for us to further diagnose the issue.


(Steve Robbins) #9

Well its not letting me upload an attachment. lol. When I play with the red bar at the beginning f the file its in sync. If I stop and start again the red bar continues from where it was stopped and the audio starts from the very beginning. Leaving the audio and video out of sync. The actual vid is just a lyric video., My first real foray into it all.
Is there an alternative way to upload the file btw?


(Jose Moreno) #10

@steverobbins You can use wetransfer.com, google drive, dropbox, mega.nz to upload files with sharing links. Wentransfer deletes itself after a week. google and dropbox need a personal account and mega.nz can be managed anonimously but sometimes it fails to do so.


(Steve Robbins) #11

Facepalms. I should have thought of that. lol.


(Steve Robbins) #12

https://drive.google.com/open?id=1r5f3mtIfTn058rvZWxyITml88jbYLtt4


(Jose Moreno) #13

@steverobbins Thanks man. As soon as we can we’ll review it and look for probable causes to this problem. Hopefully it won’t take long to find the cause of your issue, but until then keep working with your sound editor meanwhile.


(Jose Moreno) #14

@steverobbins Hey. Well we’ve got some updates on this problem. I managed to reproduce the problems immediately and so we tested for about 6 hours among different possibilities and here are some hard facts we got by:

  1. The mp3 file has a broken VBR header, so not only Pencil2D but other software and even the OS interacts with the file differently. Of course the file “sounds” and plays good with normal players, but this is the exact problem that is causing the issue. For example, if you right click and go to properties, you can see that the file is displayed to have a duration of 7:27 minutes, twice of what it has.

  2. Due to the corrupted VBR the sounds become perceptually longer and when the sound is incorrectly “mapped” into Pencil2D and other software (even VLC was saying it was longer) it creates the issue you experienced.

  3. In Pencil2D when you press playback and pause the program creates a sort of “ghosted delay” and the longer the sound is, the longer that delay will be. Since Pencil2D has a max visual length of 10K frames, the sample was longer than what Pencil2D could hold.

  4. Sound editors read the file just right so I took the liberty to re-export the sound using Audacity with the LAME 3.99.3 version codec. It worked flawlessly, no long audio, no delays. Not all MP3 codecs are the same, and from reading documentation it seems Cakewalk exports using LAME as well. Just be careful of your bitrate and if it doesn’t work in P2D, get an extra wav copy to work with it.

  5. Scribblemaniac recommended looking on your audio authoring software or editor to export with a CBR or Constant Bit Rate. I recommend working with WAV files in Pencil2D. I know the importance of MP3’s in the music bussiness but sometimes things like this happens and well as you experienced it ain’t nice, so try to use an uncompressed sound sample to work with.

  6. There’s still work to be done with the playback for sure, but since this problem points to the framework we use to create the program, only until they fix that issue (whatever it is because we don’t know :face_with_head_bandage: ) we will be able to implement proper changes to the code to avoid corner cases like this one.

That concludes the report :wink:


(Steve Robbins) #15

Kewl. the first time I tried to bounce the vid it took ages and ended up. 23 minutes long. I’ll try it all again if needed i`ll bounce the MP3 down again from the FLAC
Thank you so much for all your help