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Trim audio file while keeping timecode


Sound
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I am looking for an easy way to trim an audio file while keeping tc information.

Lets say the file starts at 00:00:00 - I want to edit out the part from 00:10:14 to 00:10:60 and the starting tc of the new file should be 00:10:14.

Is there an easy way to do it?

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Sound Forge Pro supports changing the TC stamp after editing. AFAIK, SFP cannot create a BWF from scratch but can save (or Save as) an existing BWF maintaining the metadata. You can try the SF Pro trial version of 30 days which has very few limitations.

Otherwise, a TC stamp can be changed in WaveAgent after editing thd file in yo'  favorite audio app if..  the metadata still exists.. some editing apps remove the metadata when re-saving a BWF.

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avid MC can do this, if you know what you're doing.
I suspect PT to be a able to do the same, as well as Reaper, and others.
It all depends on what you want. Setting a new Timestamp (FU, BWF does NOT carry TC) is not that hard.

 

 

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Thanks again!! You are great!

 

i am trying to find an easy way to detect audio jumps in the Zoom f6. Timecode output and file timcode of the recorder counts on but the recorded audio jumps. So if I feed Timecode output to an audio track of the recorder and the recorded audio jumps somewhere in the file there should be a difference of ltc and file tc at the end of the track. But most of the time LTC is converted at the beginning of the file, I cannot set it to read it at the end. So I thought I could just cut off the end of the file and then compare ltc  and file tc.

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Thanks again Bouke.

I could install the newest (demo) version and could find the button.

To try it out, I edited the file in logic and cut out a piece in the middle.

But it doesnt recognize the file and is stuck with the status "please wait while files are scanned".

No matter if "Expect breaks" is selected or not..

Tentacle sync finds a timecode and if I select "scan in the middle of file" it even show a different timecode from the edited part..

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9 hours ago, NewEndian said:

I had written this a little while ago to cut down large 888 BWF files that were just all day long recordings. MacOS only. No guarantees or warranties. Feel free to test it for your purposes: https://selectivesubconscious.com/888Trimmer/888Trimmer.zip

Thanks for your help!

It looks like a great tool, but I am afraid it doesnt exactl copy the file tc and audio tc is off as well..

According to the tool, the exportet file should start at 1:40:03 but it starts at 1:40:09 when I read it in tentacle sync.

 

 

 

Screenshot 2022-04-11 at 09.01.51.png

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Right now there is no easy way. The fastest way for me was to use ffworks for Mac to batch cut off the last seconds of every file,

then export (without file tc unfortunately).

Then sync those files to the originals via audio-tc, export an xml for final cut and compare the END of the original clips and the trimmed clips on the timeline.

If they align at the end, then the file-tc (or the audio-tc, depends on the way you sync) at the start of the original file and the audio tc of the cut out version (from the end of the original file) are identical.

Its a few steps but doesnt take too long.

At the same time I will try LTC Convert with "expect breaks", especially when I find differences.

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On 4/10/2022 at 8:57 PM, Sound said:

To try it out, I edited the file in logic and cut out a piece in the middle.

But it doesnt recognize the file and is stuck with the status "please wait while files are scanned".

 

Please send me the file from Logic, I know there used to be an issue with Logic files (some non-standard stuff), but I thought that was worked out.

I did a test run with LTC convert, and it works fine. (But it does not really 'do' anything except reporting.)
For fun, download this:
https://we.tl/t-MVaRKTlPWx

 

Drop it on the left side of LTC convert, enable 'expect breaks' and scan. When done, doubleclick on the filename in the interface, and it'll show you where the breaks are.

 

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I am afraid I have deleted the logic-file already.. But its not necessary for testing as your file works. :)

From my first test using the ffworks method I had a maximum shift of two frames between the original and the cut off file ends.

I dont know exactly why there should be any shift at all as there is no audio drift when the tc output is connected directly to the audio input..

and its the same file synced to itself..

But LTC convert didnt detect breaks either on the original corresponding file, so it should be fine.

But anyway, two frames for me is not a sign for an audio jump. I will continue testing.

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Eeh, I'm offering help just for debugging / fun.
As a Pro, just trash the unit and buy something that is proven to work.
Of course, all location sound stuff is HIGHLY overpriced, but what war do you want to win?
Go with the flow, my rate only with my effort on your system problems makes no sense at all.
TRASH the unit, get something that does the job,  or post on a list / forum / site with people who like to have problems.

( Sorry to sound so harsh, I have my own issues at the moment.)


 

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On 4/11/2022 at 3:03 AM, Sound said:

Thanks for your help!

It looks like a great tool, but I am afraid it doesnt exactl copy the file tc and audio tc is off as well..

According to the tool, the exportet file should start at 1:40:03 but it starts at 1:40:09 when I read it in tentacle sync.

 

 

 

Screenshot 2022-04-11 at 09.01.51.png

 

That's probably a 48048 type weird thing. If you want to send me a Zoom F6 file, it should actually be an easy fix.

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There is no 'weirdness', changing the sample rate to get TC 'right' is weird, this might fuck up things big time.
If you don't know what you're doing, step away and let the big boys take care of it.

(Insults intended, sorry...)

 

 

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32 minutes ago, Bouke said:

There is no 'weirdness', changing the sample rate to get TC 'right' is weird, this might fuck up things big time.
If you don't know what you're doing, step away and let the big boys take care of it.

(Insults intended, sorry...)

 

 

My goodness! You are very confident when you actually don't know what you're talking about. Do you know how I know that you don't know? Because nobody said anything about changing the sample rate.

 

Take a step back and try to realize that there are elements to this you're not familiar with. And seriously, you're going to insult a guy who is literally writing Broadcast Wave Format files in code? Maybe I know something about how the files and timecode works

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9 hours ago, NewEndian said:

I uploaded another version that you can toggle off the 48048 weirdness: https://selectivesubconscious.com/888Trimmer/888Trimmer.zip

Thanks, the new version seems to work!

If there would be a batch-function it would be even greater. :)

Right now, my ffworks-workflow is faster when I have to edit about 50 or more files..

 

Screenshot 2022-04-13 at 08.46.42.png

10 hours ago, Bouke said:

Eeh, I'm offering help just for debugging / fun.
As a Pro, just trash the unit and buy something that is proven to work.
Of course, all location sound stuff is HIGHLY overpriced, but what war do you want to win?
Go with the flow, my rate only with my effort on your system problems makes no sense at all.
TRASH the unit, get something that does the job,  or post on a list / forum / site with people who like to have problems.

( Sorry to sound so harsh, I have my own issues at the moment.)


 

Thanks a lot for your help, dont get me wrong, I am very grateful for your time, and your tool works.

I will definitely use it to double check the files that seem to cause problems.

I was thinking about buying something else all the time as this hast cost me LOTS of my time for weeks now.

Before I had the Mixpre 10 ii and i regret having sold it, as i never hat any issues with it.

But its a lot of weight if you use it on location and have to to a lot of things at the same time.

So its not a question of money:

At the moment there is no other recorder with six xlr-inputs and six track knobs with this size and weight.

Especially fully powered, as you can use it all day with just one NP-F Battery and dont need an external powering solution.

Mixpre 6 II could be fine, but only 4 xlr and one minijack input and only four track knobs...

I just hope the new firmware has fixed ist, just have to test.

For anyone who is interested. Here is a test file.

Zoom F6, Six channels recorded in 24bit, 48khz until max filesize reached.

https://we.tl/t-K1rOSFVFdA

10 hours ago, NewEndian said:

 

That's probably a 48048 type weird thing. If you want to send me a Zoom F6 file, it should actually be an easy fix.

If its still interesting for you:

https://we.tl/t-K1rOSFVFdA

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21 hours ago, Bouke said:

Please send me the file from Logic, I know there used to be an issue with Logic files (some non-standard stuff), but I thought that was worked out.

If its still interesting for you, I could recreate the file from logic.

I dont need it to work as I dont have to check logic-files, but maybe it helps your software.

https://we.tl/t-heGlQ4ZbLM

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8 hours ago, NewEndian said:

Because nobody said anything about changing the sample rate.

You did, you use 48048 or 48000 to identify speed for your Samples to TC calculation. (Where the frames are missing btw...)
I would use video FPS (Drop or non-drop) to give a preview about what the TC will look like.

But lets agree to disagree.

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3 hours ago, Bouke said:

You did, you use 48048 or 48000 to identify speed for your Samples to TC calculation. (Where the frames are missing btw...)
I would use video FPS (Drop or non-drop) to give a preview about what the TC will look like.

But lets agree to disagree.

Yeah sorry. It's nice that you got to think about it some more, but there was no changing of sample rate, either literally or in the file metadata. That Samples to TC calculation did need to be changed.

 

Now, do you know why it might be totally legitimate to have to make that change? Because there is a reason. And considering that anyone even make reference to 48048 plus provide a program that might deal with it, maybe it should've given a person pause before acting like an asshole right off the bat to someone he's never met.

 

As I said in my first comment, I created the program so that I could use it for my purposes, which you still know nothing about. I don't care that the frames are missing because I didn't need it. But rest assured, the program was tested with everyone in the workflow, and against our other files, and is still being used on the production now.

 

Someone asked for something to trim his files and I happened to have something, so I provided it. I happened to know why the difference between our workflows would make the timecode off (and the reasons and implementations of 48048 are weird no matter how you slice it), so I made the simple change and provided it. And all with the disclaimer that he should make sure it worked for his purposes because I didn't write it for him. And it's not going to, and that's totally fine.

 

Your attitude on the other hand, I have a problem with. Tell you what though, I'll hit the reset button if you do too.

 

6 hours ago, Sound said:

Thanks, the new version seems to work!

All good! I just happened to have it, so it was very little effort. :)

I'm afraid I have other work to do though, so I will not be adding a batch function for you. But good luck with whatever project you're on!

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On 4/13/2022 at 1:34 PM, NewEndian said:

Now, do you know why it might be totally legitimate to have to make that change? Because there is a reason.

I know about speed change for 23.976 / 24 workflows. (Old style video to 35mm, I did work on Avatar, all rushes from Mocap, including 'not so' sync sound from BWF have been processed with my software, so I think you can trust me when I state that I do know what I'm talking about.)
I also know about how Samples after Midnight convert to TC. I've spent WAY too much time on explaining that BWF DOES NOT carry TC, but a 'frame number' (Starting at 1, not 0, but that's too much into detail...)

I did not intend to criticize your work in any way, I merely wanted to state that 1000/1001 (as the 0.1% math is often described) is to be preferred over 48048, as that refers to changed sample rate to do a speed change.

I do have an attitude, not sure how long you have been around here, on on other lists, most people do know me a bit and do know that there is no real evil in it.
(I'm a coder / used to be a video editor.)
 

 

On 4/13/2022 at 1:34 PM, NewEndian said:

I'll hit the reset button if you do too.

 

Sure, why not? I did not intended to start a war, hence the disclaimer in my offending message.

 

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  • 3 months later...
On 4/10/2022 at 5:47 PM, NewEndian said:

I had written this a little while ago to cut down large 888 BWF files that were just all day long recordings. MacOS only. No guarantees or warranties. Feel free to test it for your purposes: https://selectivesubconscious.com/888Trimmer/888Trimmer.zip

Hi James,

This is such a cool tool! Unfortunately, it kept crashing when I tried opening files on my M1 mac. I have Rosetta 2 installed. If you ever expand or work on this more I know there are lots of us who could benefit from it. Building a PT session and exporting is to tedious.

FYI - The Zaxcom community would hugely benefit from this. I was trying this out on a transmitter recording (Mono, 48k, ~2HRs). Post wants me to pull a few lines from this huge file because they decided to call action right after I said I needed a minute to swap batteries and wouldn't you know it. That's the take they want to use. Trying to help them out buy no sending multi-hour file over. Zaxcom hasn't worked on their computer software as much as I would like.

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