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Rendered MP4 Files Audio/Video Out Of Sync
Hey Creative Cow! my first post
I have this annoying problem that I cannot figure out and its been driving me crazy
All of my footage from my film is PERFECTLY how I want it to be everything is in sync when viewed in the program, yet when I save it as a MP4 and view it the sound seems to be off by about half a second, the noises and sound come half a second late…
I do not know why it is doing this because when I render as Mp2 or WMV the sound and video is exactly how it looks as it does in the program but its only when i am rendering in mp4 that it does this…
Source is 1280 X 720, 29.97 frames per second
Rendering out at that as well…
Even when I posted it onto youtube the sound was off the same way it was when i viewed it on my computer
And it is the same when viewed in VLC Player or in Windows Media Player….
Someone please help as I do not want to go through my project and re-align everything to happen half a second before its supose to happen in an attempt to make it proper when its rendered…
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7 Replies
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Have you tried watching the YouTube clip on a different computer? I have seen instances where the audio and video were out of sync, but once rendered it played fine. This usually had to do with the amount of data in the video, and the system wasn’t powerful enough to process all of the information in the clip, hence the sync issue.
However, i’m at a loss with it being out of sync when viewing on YouTube, since those files are usually small enough for any system to play.
Are you playing these full-screen on YouTube? If so, try playing in the default window size and see how the sync is.
Intel i5 3570K Ivy Bridge 3.40GHz quad core
Asus P8Z77V-LK
16gb RAM
ATI Radeon HD7850 2gb
Crucial M4 SSD + Seagate Barricuda 7200rpm
Windows 7 Pro 64 -
Well the interesting thing here is that to a normal everyday person WILL NOT NOTICE this, probably even a seasoned veteran in video editing they most likely will not even notice that the audio is off…
Its just I have this one clip when a shovel goes flying and hits someones head (fake) and the sound effect I put in the program perfectly lines up at the exact moment it hits I can see this by playing the clip over and over and I can see it by seeing the wavelength in the timeline..
But since I edited the film I can tell more and I didnt exactly see the problem myself all I felt was that something was off or strange about it, it wasnt until I checked out the sounds and it happened to be half a second off…
I have a duel core system with 8 gigs of ram, shouldnt that be more than enough for my computer to handle it?
It also seems like its a permanent thing because even if I render out 5 second clips to test to see if its in sync it will still be about half a second off…
What is considered the normal for 720P video to render as bitrate in?
I am currently rendering the max bitrate 5,000,000
Thanks
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I did a couple tests, I rendered at 2,000,0000 bitrate (which is ridiculously low) and also put a two pass on it thinking it would do it better
And same result, the audio comes still half a second later:(
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I have another important thing to add…
Even though the audio or video is off when I put the out of sync video into sony vegas MAGICALLY it is in synch….
Yet on youtube and played as a file everything still happens half a second later…
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When I render the out of sync file, put it back into Vegas it is magically in sync again, so I render that file AGAIN and its still out of sync, so weird..
The performance of my laptop isnt the issue because there is no excuse why It shouldnt be able to handle a clip with a bitrate of only 2,000,000
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I guess this problem is unexplainable eh:(
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Have you found a solution? I had a similar issue.
– everything looks in sync in the project
– mp4 rendered at 1920 x 1080, 29fps (same as source file), 10mbps (source file was 25mbps) with CABAC: appears out of sync on VLC and WMP
– when I insert the mp4 file above back into vegas, it’s back in sync
– also rendered an mp4 version at 1280 x 720 and 2.3mbps: it appears slightly out of sync, less so than the higher quality versionSo far we have the same problem, but once I uploaded my apparently out-of-sync file to Vimeo, it looked just fine! So I may not have the exact same problem as you, though I haven’t tried uploading to youtube yet.
So I did some experimenting. Rendering in a different file format (m2t), even at top quality (25mbps), had no issues with playback or audio/video sync. I tried mp4 again in different resolutions and with the CAVLC codec instead of CABAC and still I had the same problem.
Wanting to try out even more different settings but tired of rendering a 26-minute video over and over again, I started rendering just a short 40-second clip. Guess what: the short clip, rendered at the same setting as my initial attempt (mp4, 1920×1080, 29fps, 10mbps, CABAC) had no noticeable audio/video syncing problems!
It appears that as the file size goes up, the sync problem appears. This is all I can provide in terms of input to this conversation, based on trial and error. I have no idea what may be causing this nor how to fix it. Now that I look more carefully at a 10-minute clip I did with the same settings a few months ago, I can perceive a slight sync issue. I hadn’t noticed it before, but the more I look at it the more I see it. But in the 26-minute clip I made this week, it’s just way too obvious.
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