Add auxiliary timecode to mxf using raw2bmx

[Tobi B]

Hi there,

we need to add an auxiliary timecode to a mxf. Not just using the -tag flag to add it as a comment but as a "real" timecode that avid picks up when you pull in the mxf. Is this possible using raw2bmx? If not, do you have another idea how we can achieve this?

Thank you very much for your help!
Tobi

[Philip de Nier]

I had a quick look and it appears that Avid auxiliary timecodes are represented as additional timecode tracks (with filler) in the physical source package. bmx only supports a single timecode and so can't be used to create files with auxiliary timecode.

Philip

[Tobi B]

Hi Philip,

thanks for your response! How difficult do you think it would be to add support for an auxiliary timecode track? I just had a quick look a the code and it seems possible too me. Would it work by replicating what is done for the start tc in AvidClip::CreateMaterialPackage() and a few changes to ClipWriter / raw2bmx? Or is there something underneath that would prevent you from adding another timecode track? If you think it's possible without doing major changes to the overall concept of bmx, I'd be happy to do the implementation.

Thanks!
Tobi

[Philip de Nier]

I'd expect it to be similar / related to how the main Avid timecode works, but I'm not sure how difficult it will be because it depends on the specific requirements Avid has for the way the auxiliary timecodes are represented. Avid can be very particular about how things are represented in their native format across different products.

Philip

[Tobi B]

So I tried a few different things, but nothing really worked so far... I tried adding the auxiliary timecode track to the mastermob or the sourcemob but it would never show up in avid. I followed the existing implementation for the "normal" timecode. Do you have any idea what might be missing?

[Philip de Nier]

The way to approach this is to create a set of files with and without auxiliary timecode (all variations), analyse the files to see what needs to be added (by comparing the files with and without the auxiliary timecode) and then implement those changes. The XML and text dump tools in the AAF SDK are useful for analysing the Avid files.

Philip

[Tobi B]

Thanks for the good suggestions, that's what I've been doing. I'll continue my investigation...

Tobi

[Tobi B]

Hi Philip,

after a few more experiments I was able to implement this feature. Is is possible te get the changes integrated into the master?

Thanks!
Tobi

[Philip de Nier]

Yes, that's possible. If it's a relatively simple set of changes then a git format patch file would be sufficient and otherwise create a fork of the git repository on Sourceforge and add the updates to that. I'll review the changes and push once I'm happy.

Philip

[Tobi B]

That sounds good, thanks! I just gained some new insights and I should be able to modify my implementation so that it allows adding multiple auxiliary timecode tracks. Once this is done, I'll send you the patch file.

[Arnaud Careo]

Hello,
I would also be much interested by this feature.
Has the patch been merged yet?

Thanks,
Arnaud

[Tobi B]

So... I finally got to implementing support for up to 5 aux timecodes. Here comes the patch file. I hope everything complies to your standards, feel free to change as required.

Thanks,
Tobi

[Arnaud Careo]

Thanks a lot,

It works great!

[Philip de Nier]

Thanks for this. I'll take a closer look when I get some more time.

Philip

[Philip de Nier]

I've pushed the commit with a change to use Timecode::GetOffset() rather than ToFrames and some minor cosmetics.

Philip

[Tobi B]

Great, thank you very much!