When I'm trying to convert .swf to .mp4. I got error:
what software (eg, adobe media encoder) are you using to convert?
post them for issues using their software.
It would be a good idea BUT I was using multiple converters and noone is working,
If you use lots of different non-Adobe software and it all fails, then it still doesn't make it Adobe's problem. Very few SWF files would be even suitable for this conversion, perhaps you expect too much of them. Most SWF files have to hefts-authored, not converted.
1. if you were using adobe sofware to convert the swf, then posting on that software forum would be appropriate.
2. the answer from that forum might be, yeah that's common or maybe someone would suggest software settings that would make conversion more likely to be successful.
3. maybe the swf is the problem and maybe the swf is corrupt. but error messages from online converters doesn't establish the swf is corrupt and doesn't establish (or even suggest) the swf is the problem.
4. maybe there exists a fla that's not corrupt and animate publishes a corrupt swf when using that fla. that would be an animate issue and this would be the correct forum.
tl;dr - there's nothing you're posting that indicates any animate or other adobe program issue.
So Is there any official software for converting?
In the general case there is no software for converting. Not official, not any. If there was a magic converter Flash would have been closed down years ago, rather than having a 3 year period for people to do the work. Yes, lot's of work and it's far too late to start!
If you have an SWF which always plays the same, has no interactivity, and has no sound, you don't need a converter. You can just play it and use screen capture software to get a copy of the video it played. Job done - but do it NOW, before Flash Player finishes.
adobe media encoder (ame) is the adobe program to convert to video, but it's not going to import a swf. you have to use another adobe program (eg, animate or after effects) to import the swf and then export to ame.
Its got sound. And Im doing it in Animate, so how to import it to ame?
Animate can export HTML5 based animation. You may need significant changes to your project, but this how you solve it - not with a magic converter.
Swivel is perfect for the job, it works for everyone.