Importing WAV results in incorrect timecode and "media start" offset

[gallatin604]

Hi,

I'm a developer for a company that built an Adobe extension for audio files. We have noticed a problem recently when we attempt to import WAV files into Premiere Pro. 

When we import a WAV file, the metadata for "Media Start" is incorrectly set. The audio file should simply start at 0:00:00, but there is an offset, in this case of 12 seconds as you can see from the photo:

Media Start set to 12 seconds on import of WAV

The audiofile plays just fine, there is no 12 second delay, but the incorrect metadata is causing problems when we try and swap between MP3 and WAV versions (which our extension does frequently).

When importing the same song that has been converted to MP3, there is no incorrect offset as you can see here:

MP3 version with NO offset

Here is the problem: when our extension swaps the MP3 version for the lossless WAV (essentially using the "replace footage" functionality), the metadata offset messes things up as you can see here:

Danger Lines from Media Start Time differential

So my question is: why would Premiere set "Media Start" to 12 seconds instead of 0:00:00 for the WAV file?

We have tried other WAVs from our library and there continues to be a weird offset, thought the actual size of the offset varies. These are simple WAV bounces from Pro Tools, so I cannot imagine we are editing the metadata in any way.

Any help is greatly appreciated, thanks!

[Bruce Bullis]

Not sure, but I suspect there's additional start time metadata in the file. I know Media Composer sees different start times in some .wav files than PPro does; not sure about ProTools' usage.

[grantwNZ]

I have the same problem. Did you find a solution to this? 

[mstegner · Accepted solution]

The WAV file is actually a Broadcast Wave file, with start offset information in the metadata.  Premiere reads the B-Wav metadata and is doing exactly what is designed to do.  You need to either stop writing B-Wave metadata into the audio file on creation or adjust the timecode via right click,  “Modify>Timecode>Timecode…”.  Look for a setting in what ever application or device you are using to create the wave file.

When converting the file to MP3, the offset metadata is stripped out and Premiere reads it as starting at zero.  That is why you don’t see it in the MP3.

This can be seen in the Metadata display under “Metadata Panel>BWF Broadcast Audio Extension>Time Reference…”

[Path 88 Productions]

Premiere reads the B-Wav metadata and is doing exactly what is designed to do.

Forgive my ignorance, but what possible benefit does meta data offer by doing "Exactly what it designed to do" in this instance?  Seems like it's creating problems.   Who in their right mind want offset timecode?

Also, can I strip out the infor that's part of Metadata Panel>BWF Broadcast Audio Extension>Time Reference without damaging the accurate timecode information that I'd still like to, and need to, use? 

[R Neil Haugen]

No, Premiere is using the data as that metadata was intended to be used. Which, for those expecting that behavior, exactly as expected.

That it is not what you are setup to use simply indicates a lack of understanding on how to use a pretty technical bit of setup. And that's not a slight on you at all, just something that none of us understands until we've worked with it a bit.

There's a ton of little details like this in video/audio post work. Many little minefields all over the place. But very useful for those who know how.

Neil

[Path 88 Productions]

Of course I'm ignornat.  That's why I'm asking.  I can't fathom why offset timecode makes sense for anyone, but I'd love an explanation.  Maybe it's some weird DAW thing?  I don't know.  As you say, apparently, someone out there in post-production-land expects this odd behavior.  

Aside from that, any ideas on how to make the source timecode from BWF .WAV's track accurately with the new "Metadata and Timecode Burn-In"?   

I'm desperately trying to figure this out becuse it will be a massive help to me providing previews w/tc-burn-in to my team.

[R Neil Haugen]

I'm not up personally on all the arcanities of audio practice ... that's an area I know enough of to know that much of the time, I want a more experienced person looking over my shoulder if not just doing it.

mstegner is one of the top devs working on this, and would be able to give the full details. It's also something that many of the helpers over on the Audition forum could explain.

Neil

[Path 88 Productions]

Thanks for the advice, appreciate it.  I'll continue to try and track this down and see where the dev team is at on it.  The new "Metadata and Timecode Burn-In" effect is sooo close to being an ideal solution for what I'm trying to do with video previews including TC burn-in.

I'm hoping they can add an option that allows the effect to acces this metadata: Dynamic Media -> Start Timecode -> Time Value.  If at all possible, that might be a solution.

[Mike-Berry]

Hi -

One common use of broadcast wav timecode is when you are shooting split sound, where the video and audio files are being written by different devices. The devices are sync-locked to a timecode source, but naturally the actual beginning of the file that each actually writes will not be exactly aligned. So each device writes the timecode of the start into the file, which allows Premiere Pro to precisely synchonize them.
You can extend this example to any of the cases where the bwav represents the audio companion to a video file and needs timecode to achieve synchronization.

Mike

[Path 88 Productions]

This is true and exactly the situation my production is doing.

So my big problem with all this is that when making dailiy previews for my team, the audio track, when using the new "Meta Data Timecode" effect, will display the OFFSET numbers and NOT the numbers we require.  Which would be, as you say, this stuff:

"each device writes the timecode of the start into the file, which allows Premiere Pro to precisely synchonize them."

Desperately trying to get Premiere to use the same numbers on screen with this effect that it's displaying as the surce timecode numbers.  Seems like this shouldn;t be an issue, yet here we are.  Got something funky happening.  More info of my problem listed here:

https://community.adobe.com/t5/premiere-pro-beta-discussions/discuss-new-metadata-amp-timecode-burn-...

[mstegner]

If you need to change a lot of files that already have B-Wav metadata in it, you can probably use Audition to batch save the files, and uncheck the box for "Include markers and other metadata". 

[Path 88 Productions]

I've not used Audition.  Any tutorials showing how this processs would be done?  I have a bunch of .wav files I'd like to remove B-Wav metadata.