[FFmpeg-user] Understanding how to use FFmpeg on macOS

[Bouke / VideoToolShed]

> On 23 Mar 2020, at 11:29, Ted Park <kumowoon1025 at gmail.com> wrote:
> 
> Hi,

Hi all, since I’m the developer, (btw, @ Ted, this is the project you’ve helped me on with audio patchting), let me comment.
> 
> You don’t need binaries to be signed to run on Catalina. If you can run ffmpeg manually other programs probably will be able to as well. If apps have hardened runtime enabled (which is to say all notarized apps) then Gabry is right, usually they can’t use anything other than stuff included in the app and system libraries, but an app that asks for an external library location presumably has the entitlement granting them that exception.

What I do is xatrr -dr com.apple.quarantine (ffpath), and that seems to work just fine.
(And yes, my app is notarised.)


> As far as support, the quicktime framework has been deprecated on macOS and is unavailable in Catalina. The replacement is AVFoundtion which dropped support for a lot of features in the format, including some that are still in use (basically any function/codec not available 64bit).

This is what it is about. the OP (Tangier) want to do a destructive change of TC on source files.
I’ve already told him that this is a problem now due to the changes in the OS (removal of QuickTime)..
Previous version of my work could do that with a plugin, based on the quicktime framework.
But that is gone. Now, ‘some’ QT’s have TC written as frame number in the beginning of the mdat chunk, but some not.
I can parse ‘some’ TC chunks, that tell me frame duration / frame rate and alike, but for the life of me I can’t find where the actual TC data is stored.
(And I can’t say I understand the Apple documentation.)

I’m pretty sure this is in the FFmpeg source code somewhere, but I can’t read C….

> How did you convert the mts to a mov? I am pretty sure you have to change the underlying structure of the video to convert from one to the other.

That’s probably FFmpeg work, but then there is no issue, as FFmpeg can easilly add a new TC when copying / transcoding to a new file.
The devil is in the destructive TC changing, but that is not something FFmpeg is supposed to do.

Bouke

> 
> Regards,
> Ted Park
> 
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