Changing how audio is embedded in Quicktime? (Media Express)

Do you have questions about Desktop Video, Converters, Routers and Monitoring?
  • Author
  • Message
Offline
User avatar

Perry

  • Posts: 173
  • Joined: Mon Sep 10, 2012 1:54 pm
  • Location: Boston, MA

Changing how audio is embedded in Quicktime? (Media Express)

PostTue Feb 27, 2018 3:41 pm

Here are two images from Quicktime Player, of the audio embedded in a file.

The first is from Final Cut Pro 7, of a capture from a tape with 4 channels of audio. The audio can be grouped (as you see here, with Soundtrack 1 as Stereo, and channels 3 and 4 as separate mono files in Soundtrack 2 and Soundtrack 3, respectively):

Image

When capturing from Media Express, the resulting file has 1 soundtrack, but that soundtrack contains all the channels captured:

Image

The problem with this arrangement is that it's difficult to remove or quickly isolate soundtracks from the file. For example, our client wants us to deliver captured tapes that have two different language soundtracks as two different ProRes files, one with each language. That is, if a tape has 2 stereo tracks (1/2 and 3/4, each paired) we would capture the tape with all four channels, disable two of them in Quicktime Pro player, Save As to a new file, and then in that new file, delete the unused channels. The result is a Quicktime file that only contains the audio used. We also need to deliver WAV files of the tapes that have M&E and narration tracks, which are typically separate mono channels. With the FCP setup, you can just check or uncheck entire soundtracks and quickly export the audio right from Quicktime player. With the Media Express method, it's much more laborious, since you have to re-assign each channel for each export.

With files captured with Media Express, we can do the same thing, but only with channel assignments (selecting "Unused" for the channels we don't want). The problem is that we want to eliminate any chance that someone might enable these tracks later. When the audio channels are embedded in a common soundtrack, you can't delete them, you can just assign channels or disable. But they can always be re-enabled.

So is there any way that we can capture with Media Express to get a file consistent with those that we get from FCP? I can't find a setting for it in the application. If not, can the application be modified to do this in a future version? Even as an option in the preferences?

Thanks!
Perry Paolantonio
Gamma Ray Digital - 119 Braintree St #505 - Allston, MA 02134
6k Film Scanning -- Film Restoration -- Blu-ray/DVD Authoring -- Encoding
www.gammaraydigital.com
Online

Andrew Kolakowski

  • Posts: 4273
  • Joined: Tue Sep 11, 2012 10:20 am

Re: Changing how audio is embedded in Quicktime? (Media Expr

PostTue Feb 27, 2018 4:33 pm

No- it's hard coded in the MediaExpress, so try "forcing" BM to change it in next version by writing request.
I also think many mono/discrete tracks is better approach than 1x multichannel track.

For now what you can do is to re-wrap this files with ffmpeg:

ffmpeg -guess_layout_max 0 -i "source.mov" -filter_complex channelsplit=8c -ac 1 -c:v copy -c:a pcm_s24le "out.mov"

this will copy video data and split 1x8 channel track into 8x mono (keeping default order).

Or with this you can actually remove unwanted channels + re-route as you wish:

ffmpeg -guess_layout_max 0 -i "source.mov" -filter_complex "pan=4c|c0=c3|c1=c2|c2=c1|c3=c0,channelsplit=4c" -ac 1 -c:v copy -c:a pcm_s24le "out.mov"

in the example above I've taken only first 4 channels and saved them in reverse order. Just note that channel numbers starts from 0 not 1.
Number of all channels for pan and channelsplit should always match- like in this case it's 4c (first we route them then make sure they are split into single mono tracks).

If you want to further channels grouping into track then read this:

https://trac.ffmpeg.org/wiki/AudioChannelManipulation

ffmpeg -guess_layout_max 0 -i "source.mov" -filter_complex "pan=4c|c0=c3|c1=c2|c2=c1|c3=c0[out1];pan=4c|c0=c4|c1=c5|c2=c6|c3=c7[out2]" -map 0:0 -c:v copy -map [out1] -map [out2] -c:a pcm_s24le "out.mov"

this will take first 4 channel reverse order and make track 1 out of it as well as take channels 4-7 and make 2nd 4 channels track. You end up with video and 2x4channels tracks.
Last edited by Andrew Kolakowski on Tue Feb 27, 2018 5:21 pm, edited 2 times in total.
Offline
User avatar

Perry

  • Posts: 173
  • Joined: Mon Sep 10, 2012 1:54 pm
  • Location: Boston, MA

Re: Changing how audio is embedded in Quicktime? (Media Expr

PostTue Feb 27, 2018 5:20 pm

Thanks. We're not interested in doing this in ffmpeg. If it can't be done in Media Express we'll just keep using FCP 7. I was hoping to upgrade that computer to a newer OS (which FCP7 can't run on), and switch to Media Express for capture but discovered this issue when testing.

Hopefully BMD will add this as an option. It's how we've worked for the past 18 years in FCP-captured files, and we have a lot of scripts and other tools written that depend on audio being set up like this. It's not worth the effort to change that stuff at this point.
Perry Paolantonio
Gamma Ray Digital - 119 Braintree St #505 - Allston, MA 02134
6k Film Scanning -- Film Restoration -- Blu-ray/DVD Authoring -- Encoding
www.gammaraydigital.com
Online

Andrew Kolakowski

  • Posts: 4273
  • Joined: Tue Sep 11, 2012 10:20 am

Re: Changing how audio is embedded in Quicktime? (Media Expr

PostTue Feb 27, 2018 5:23 pm

To be honest I would not count on flexible grouping etc in MediaExpress. Unlikely to ever happen.
Capturing into 8x mono tracks may happen although I think it was already requested in the past and ignored by BM.
Other option is Telestrema Switch which allows allow for full audio manipulation including tagging etc. (and supports re-wrapping).
There is also quite a powerful tool from Cinedeck guys (https://cinextools.com), but this is quite expensive. It also feels like a must for people who do localisation/versioning though.
Offline
User avatar

JPOwens

  • Posts: 1378
  • Joined: Fri Apr 12, 2013 8:04 pm
  • Location: Victoria, British Columbia, Canada

Re: Changing how audio is embedded in Quicktime? (Media Expr

PostWed Feb 28, 2018 4:23 pm

Andrew Kolakowski wrote:Other option is Telestrema Switch which allows allow for full audio manipulation including tagging etc. (and supports re-wrapping).


Thumbs up.

You are looking at a "re-wrapping" application. Switch is one, CineXTools is another. If you had access to something like Telestream "Episode" (discontinued), that is another option.

jPo, CSI
Offline
User avatar

Perry

  • Posts: 173
  • Joined: Mon Sep 10, 2012 1:54 pm
  • Location: Boston, MA

Re: Changing how audio is embedded in Quicktime? (Media Expr

PostWed Feb 28, 2018 4:25 pm

Yeah - this isn't worth the extra step of going to another application to re-wrap. If we can't do it in Media Express during the capture, we'll just keep using FCP7.

These days the only thing we use FCP for is tape capture, which it's great at. but it'd be nice to upgrade those machines since they're stuck on 10.6.8. Basic things like browsing the web for software updates are becoming untenable on an OS that old because we can't update browsers anymore.
Perry Paolantonio
Gamma Ray Digital - 119 Braintree St #505 - Allston, MA 02134
6k Film Scanning -- Film Restoration -- Blu-ray/DVD Authoring -- Encoding
www.gammaraydigital.com
Online

Andrew Kolakowski

  • Posts: 4273
  • Joined: Tue Sep 11, 2012 10:20 am

Re: Changing how audio is embedded in Quicktime? (Media Expr

PostWed Feb 28, 2018 6:04 pm

Look at different capture options- there are some.
For Mac Tools-On-Air are not cheap, but should be very stable. I don't remember if they offered channels grouping etc. Now they also have Linux version which may be interesting.

Return to Post Production

Who is online

Users browsing this forum: No registered users and 7 guests