-
Audio drift problem when compressing to MPEG2
Hi Everyone,
I have a project that is just over 9min that I exported from FCP as a QuickTime Movie. Everything is in sync in FCP on the timeline and is still in sync in the exported QuickTime Movie.
I am using Compressor 3.5.1 to compress to MPEG2 using the following settings:
Two pass VBS Best
Avg bit rate 6.2
Max bit rate 7.7
motion estimation BestAnd Audio is AC3 at 48kHz, 192kbps.
When I bring the MPEG2 stream into DVDSP, the audio starts off in sync, but starts to drift ever so slightly around 7 minutes in.
Any thoughts?
Thanks!
Chris -
7 Replies
-
Hi Dave, The source footage is 48k as well.
-
Everything is 29.97.
I did notice that there are some differences in Audio Formats. My sequence is 32-bit floating-point and my source footage is 16 bit integer. This is lingo I am not familiar with.
-
In my “Sequence > Settings” section, the audio settings is set to 48k, 16-bit, channel grouped. I was expecting to see it say “32 bit floating point” and just change it to match the “16 bit integer” of the source footage. Am I looking in the wrong place?
Thanks for your help. I greatly appreciate your time and expertise.
-
[Dave LaRonde] “You’ve isolated the one single attribute between footage and timeline that’s different… and the timeline doesn’t match the source footage. What do YOU think you ought o do next? “
Dave, you have him chasing his tail on this one. 32-bit floating point is the normal default setting for FCP sequences. Its not really a mismatch. I don’t know whats causing his problem, but it ain’t this.
-
[Dave LaRonde] “So then — what are some of those other causes, smart guy?
“He certainly has a puzzling problem. If everything he has told us is correct, there should be no problem.
Perhaps he has some MP3 or other compressed audio in the timeline? Even at the correct sample/bit rate, it has been known to cause unpredictable behavior.
I wasn’t trying to be disrespectful…you certainly have a great deal of expertise and I have learned a lot from your posts…but if you look in the browser at any sequence you create, it will be 32-bit floating point, unless you manually go in and mess with the preset. It really can’t be the issue or else everyone would not be able encode anything in sync. It would be happening all the time.
-
I tried another handful of things yesterday:
1) I played with different settings in compressor. All lead to the same problem.
2) Tried bringing the Quicktime movie into DVDSP directly and letting it encode it there. Still have the same problem.
3) Took the Quicktime movie into Toast and let it encode and burn it. Problem gone. I had to get my master out yesterday, so I went with this and made it work.
Very strange indeed. Thanks to both of you for your help troubleshooting.
-
Glad you got it to work. If you have some time, you should do some tests on other material and see if you still have a problem. Something may be up with your system that might require trashing prefs or re-installing. Toast uses its own encoder, so it would not be affected by the issue that you are experiencing with FCS.
Reply to this Discussion! Login or Sign Up