Convert 3D video and 2D video to 24 or 48 fps (like The Hobbit) without re-encoding

[maldon]

I was wondering how I can convert a 3D video to 24 fps or 48 fps. I wanted to try this with the Blu-ray of The Hobbit: An Unexpected Journey (3D MVC).

To convert 23.976 2D video to 24 fps without re-encoding I use UsEac3to but with 3D video I understand I can't as there is a different video layer (MVC). I figure that the best option to do this is to use tsMuxeR. After adding the video file I select below "Change fps: 24" in the main video and in the MVC video. There is no option for 48 fps.

I have one question:

Is it correct to use UsEac3to or tsMuxeR to convert 2D and 3D to 24 fps without re-encoding or is there some kind of unwanted anomaly that I am not being able to perceive? I would like to use software that allows me to do this with all the guarantees that it will not produce any artifacts in the resulting video.

[von Suppé]

Have you thought about audio and subtitles speeds? These also have to be changed if you're changing video speed.

[maldon]

Yes, I can convert the audio from 23.976 to 24 fps with UsEac3to or use other software. With 48 fps I think there would be a problem.

Anyway, let's suppose that I am only going to convert 2D and 3D from 23.976 to 24 fps. What software should I use that guarantees no artifacts?

[von Suppé]

Don't know about the MVC-layer of 3D, but a 2D AVC stream (of 3D or 2D) can be sped-up with eac3to. I use UsEac3to as frontend.
If you target to mux the 2D stream in mkv, rewriting timestamps to 24fps can also be done by MKVToolNix. Set "Default duration/FPS" to 24p and check the "Fix bitstream timing info"-box. Works only for AVC.

Both ways go without recoding; it's just rewriting timestamps in the elementary videostream.

[Emulgator]

I think 3D-BD is legal only in 23.976fps.

[cubicibo]

Correct, MVC shall only be presented in 23.976, 50 and 59.94.

[maldon]

Thank you very much to all of you.

Two things:

1- If I convert a 2D video from 23.976 to 24 fps with tsMuxeR, UsEac3to or MKVToolNix can there be stuttering or some kind of artifact? That's what worries me the most, to do a conversion and believe that it is free of some kind of artifacts because I don't know how to recognize some of them. I suppose it can also be done with FFmpeg but I don't know if it can be done without re-encoding.

2 - Regarding what you say, I found this:

HDMI 3D standard allows only 23.976Hz for MVC stream

So, if instead of creating a BD-3DMVC I create a MKV-3DMVC or a M2TS-3DMVC… will the conversion to 24 fps work or will it not work because the HDMI standard for 3D does not allow it?

[Emulgator]

You may just try your luck, demux/reflag/remux, feed it to your playback chain and report your findings.

[von Suppé]

I did not know that videospeed can be changed with tsMuxer. Never done it.
And I wouldn't know how to change speed of a MVC stream to 24fps (or any framerate, if possible).

[SeeMoreDigital]

Thank you very much to all of you.

Two things:

1- If I convert a 2D video from 23.976 to 24 fps with tsMuxeR, UsEac3to or MKVToolNix can there be stuttering or some kind of artifact? That's what worries me the most, to do a conversion and believe that it is free of some kind of artifacts because I don't know how to recognize some of them. I suppose it can also be done with FFmpeg but I don't know if it can be done without re-encoding.Not in my experience. Even in the days before Blu-ray discs I encoded many MPEG-2 DVD (PAL and NTSC) sources to AVC at 24.000 fps.

And given that 24.000fps MPEG-2, VC-1 and AVC video is supported in the Blu-ray specification, there should not be a problem.

[maldon]

Ok. I guess with the new MV-HEVC codec it will be possible 24 fps, 48 fps and not only 23.976 fps. I don't know if anyone knows anything about it.