OT: avoiding audio compression in DVD project in Final Cut Pro

Hello all

I have tried a number of online sources, without success, in search of an answer to this problem. Given that the audio side of the project has been recorded and mixed in SawStudio, I hope some of the good folks here may be willing to contribute their thoughts.

The situation is that when I ask Final Cut Pro to create a DVD from an edited audio/video file, I find that the higher- or mid-level audio has been severely compressed - typically by 12 dB or more - compared with the original levels. Combine this with the inevitably audible 'pumping' as the system engages or releases, and you can imagine why the result is unacceptable.

At one point I wondered if these audio effects were present only in cases where the file had to be compressed in order to fit on the DVD - but I've tried rendering just a 1 Gb section of the file to a disc, and the audio is still mangled, so the processing seems to be applied by default. And the currently unsolvable problem is how to remove or defeat the effects.

This is the first video project I've been involved in, so I have no relevant experience to draw on. None of the obvious online sources I've tried even seems to acknowledge that there's an issue. Is there something obvious I'm missing (a 'don't mess with the audio' button, for example!) or are there at least some suggested approaches I could take, in search of an answer?

Perplexed, but hopeful,

John

What format is the audio in that you imported into FCP?

It's a 44.1, 16 bit stereo wav file. No compression, but with levels set so that peaks reach to 1dB below maximum.

Just in case it's relevant, I should add that when we check the levels of the imported audio in FCP itself, they are exactly the same as in the original edited file. It's only when we ask FCP to create a DVD from the audio/video we've inputted, and then measure the audio levels on the actual disc, that the very obvious problems with the sound are observed.

John

Quote:

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Originally Posted by JR1

It's a 44.1, 16 bit stereo wav file. No compression, but with levels set so that peaks reach to 1dB below maximum.

Just in case it's relevant, I should add that when we check the levels of the imported audio in FCP itself, they are exactly the same as in the original edited file. It's only when we ask FCP to create a DVD from the audio/video we've inputted, and then measure the audio levels on the actual disc, that the very obvious problems with the sound are observed.

John

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I know it's a work-around, but could you render the audio from FCP, then burn a DVD via a third-party app?

Thanks: that does seem to be the most practical approach! There seem to be a number of possible apps for the task: has anyone a recommendation, from personal experience, of a suitable, straightforward one to use?

Secondly, though, I'm still interested to understand the reason that FCP itself, when it creates a DVD, crunches the audio in such an obvious and unpleasant way, and how that processing can be avoided or defeated. All thoughts, on any of these matters, gratefully received.


Still perplexed

John

Is it possible that FCP is building a surround mix with a bunch of compressed streams, (either instead or as well as an uncompressed stereo mix) and you’re listening to the L&R channels of the compressed mix?

You have to reduce the bandwidth of the video to increase the resolution of the audio, as DVD has a maximum streaming rate. Though, I am not sure this is the source of your issue.

Thanks for the helpful ideas and questions offered here so far. In response I can say:

1. We have tried the 'use a third party app to burn the DVD' approach, using DVD Creator, and we find exactly the same unwanted compression of audio dynamic range as when we use FCP for the same purpose.

2. To expand on my comments earlier in this thread, I should say that, if we simply upload the video to YouTube, then measure the audio levels as the uploaded file is replaying, the audio levels are not compressed. It's only if we create a DVD, and measure the levels on the disc itself, that the compression is evident.

3. My understanding of FCP is that by default, with audio, it simply creates a standard 2 track stereo output. I'm told that to produce something more complex, like a surround mix, would require making a deliberate choice from options in a submenu. At this stage, basic stereo is causing enough problems: delving into submenus is something I haven't even contemplated!

4. I've also tried dropping the existing files (of which the video was shot in high def) into a new standard def project, as a means of reducing the bandwidth. But that meant that the resulting video quality was notably compromised, so I didn't pursue the experiment.

This problem can't be unsolvable (?) but I haven't found the answer yet.

Thanks again for all thoughts so far - and for any others that may yet occur to anyone!


John

John,

I am not a FC guy, but in the past have experienced similar results with Premiere Pro. If FC gives you the option to render as MPEG-2 instead of MPEG-2 for DVD, you may achieve a better result. In Premiere, the MPEG-2 for DVD seems (seemed) to have a compression attribute related to Dolby Digital.

Quote:

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Originally Posted by JR1

1. We have tried the 'use a third party app to burn the DVD' approach, using DVD Creator, and we find exactly the same unwanted compression of audio dynamic range as when we use FCP for the same purpose.

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This seems like a red flag of some kind. It's apparently not a FCP-specific issue.