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10/01/2017 07:29:19

ukBertyMuvizu mogulExperimental user
ukBerty
Posts: 976
A bit technical here, but what frame rate is used for image sequences out of Muvizu ?

I am having dialogue sync issues and I think this is the cause....

I output as a PNG sequence from Muvizu and get a WAV file as well. I import into HitFIlm and put my WAV alongside my sequence. The frame rate I set my composite shot to will determine how many frames the audio will cover. On longer shots I think I've notice the audio "go out".

So how many frames do I get per second out of Muvizu using image sequences ?

(Don't just guess please)
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10/01/2017 08:00:02

MrDrWho13Muvizu mogulExperimental user
MrDrWho13
Posts: 2221
I'm fairly sure it's 25fps.
You could try exporting avi or mp4 to see what frame rate they are.
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10/01/2017 08:02:52

ukBertyMuvizu mogulExperimental user
ukBerty
Posts: 976
....but that would tell me the frame-rate for AVI/MP4 not necessarily for image sequences.....

I need a definitive answer.
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10/01/2017 08:45:26

ritsmer
ritsmer
Posts: 110
Just tried to render 10 seconds as .png's. The render started at 0:00.

In the resulting folder there are precisely 250 .png's meaning that the frame rate is 25 Fps.

Then I copy/pasted all .png's to a Vegas 25 Fps timeline with the setting Still image length = 1 frame. This gave 10 seconds of video. Thereafter I put the corresponding wav file to the same timeline - and that gave precisely 10 seconds of sound.


Then it gets interesting: I rendered the same 10 seconds as .mp4 1920 at some 10 Mbps and put this onto the same Vegas TL.
Surprise: the .png pictures and the mp4 video seem to be 100% synchronous BUT the audio is coming too fast by a little more than 1 frame.
edited by ritsmer on 10/01/2017
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10/01/2017 08:56:53

ukBertyMuvizu mogulExperimental user
ukBerty
Posts: 976
Thanks ritsmer - yes - I guess that's what I should have done !

It can confirm I have the official answer - 25fps it is.

Now to adjust my defaults......
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10/01/2017 09:06:06

ritsmer
ritsmer
Posts: 110
You are welcome.

Pls. see the addendum to the above post.

Edit: It seems that the timeshift is close to 47 milliseconds...
edited by ritsmer on 10/01/2017
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10/01/2017 09:13:17

ukBertyMuvizu mogulExperimental user
ukBerty
Posts: 976
ritsmer -so which are you saying is correct ?
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10/01/2017 10:09:09

ritsmer
ritsmer
Posts: 110
Difficult to say as I always only use the video from Muvizu and add sounds, Foley, music etc. in Sony Vegas.
I do have many of the sounds in Muvizu too, however - to be able to synchronize the movements etc. - but I do not use the rendered audio from Muvizu.

For the time being I make some experiments with a drummer girl synchronized to All Cats Are Grey by The Cure - and some days ago I noticed that the .mp4 rendering from Muvizu was a little out of sync as to video/audio.


That said, I just made another render of your and my experiment - this time to .avi/Microsoft video 1 - and this audio has the same timing as in the .wav from the .png rendering. file.

So - to me - it seems that it is the .mp4 audio output that is a little time shifted (by some 47 milliseconds) -

But I hope that one of the Muvizu Staff Gurus will cut in and enlighten us.
edited by ritsmer on 10/01/2017
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10/01/2017 15:58:11

PatMarrNCMuvizu mogul
PatMarrNC
Posts: 1742
Interesting that the audio is off by 1 frame. It might be a worthwhile test to compare the original audio to the audio generated by Muvizu to see if they are the same

I had a similar problem a while back, and it turned out that I had somehow started with a video template for 24fps. Once I changed the video template back to 25 fps the problem resolved.
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10/01/2017 16:43:29

ritsmer
ritsmer
Posts: 110
Good idea.

The .mp4 output is not shifted by precisely 1 frame - which would be 40 ms at 25 Fps - but by some strange 47 ms.
24 Fps would give 41.7 ms per frame.

I have checked the .mp4 file and it is 25 Fps progressive as expected.

Comparing to the original audio (the one imported to Muvizu) shows that the .png output (the separate wav file) and the .avi output are the most accurate.
By "most accurate" i mean that it they are both shifted by only about 7 ms - but it is 7 ms forward as the .mp4 output is shifted about 47 ms forward.
edited by ritsmer on 10/01/2017
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10/01/2017 19:00:05

PatMarrNCMuvizu mogul
PatMarrNC
Posts: 1742
another thing that might change the synchronization of sound is whether a WAV file was used or an MP3. MP3 files typically have some buffer added to the front of the file that adds dead space between the file's start and the point at which sound starts playing.

Stated differently, If you take a WAV file and convert it to MP3 without any other change, and put them both on adjacent timelines, the WAV file will start playing first. I don't know whether/how Muvizu accounts for that padding or whether it would affect the lip synch.

I do know that the difference between MP3 and WAV is an ongoing topic on music collaboration sites where people play along with somebody else's track, then save their track in a different format than the original track, and then the collaborators wonder why the two tracks won't line up on the time line when both tracks start at the same place.

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edited by PatMarrNC on 10/01/2017
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