Handbrake: Change framerate does not what's expected

[RubenKelevra]

Please describe the problem or feature request in detail:

If I got a DVD as input and select deinterlace and 24p constant as output I would expect a 25p to 24p slowdown as well as a change in the audio tone (due the slowdown). But it looks like only some of the 25p frames are left out leaving a gaps in motion behind.

This is not exactly was I would suspect by a fps change.

There is no real usecase for the current behavoir, except if you want to reduce the fps from 60 to 30 or something similar (who the heck whats this?)

So if you want to remain the current behavoir on this setting page, I would love to see a new filter on the filter page which adds the ability to slow down/speed up the video from a selectable source framerate to a selectable destination bitrate.

So the 23.somthing-bullshit is speedup-able to 24 fps and the 25-bullshit is slowdownable to 24 fps. :)

Sure, you need to add a audio-filter for this as well, which change the sampling rate back to the original (if the format does not support the new sampling rate - which should be in favoir I guess.

What are the steps to reproduce this problem:

-Load a DVD
-Select deinterlace
-Change fps from "source" to "24p constant"

What version of HandBrake you are running:

1.0.3

What operating system and version and you running (e.g. OSX 10.11, Windows 7, Ubuntu 14):

Linux 4.10.3

[bradleysepos]

This is not exactly was I would suspect by a fps change.

There is no real usecase for the current behavoir, except if you want to reduce the fps from 60 to 30 or something similar (who the heck whats this?)

This is actually the most common and desired behavior. You appear to be looking for a video editor/NLE. HandBrake is not one.

[RubenKelevra]

@bradleysepos Well as far as I understand Handbrake should be the all-in-one transcoding solution from DVDs and Blurays to video files for different devices. As well as encoding videos for youtube at a given qualtiy.

PAL-DVDs have a defect, they are played back at the wrong framerate, analog to NTSC-DVDs which are played back with Telecine. Since you got a filter for this, it would be fair to add a filter for PAL-DVDs as well. :)

But I understand your critism and I guess I had understood the framerate-setting on the encoder tab wrong. I gonna add a feature request for a filter for this.

[jstebbins]

I'll start by saying I'm not against a filter such as this. But it can't work the way you describe for a variety of reasons.

Basically, what you are asking for is something that changes the playback speed of audio and video by some fraction that you have defined as being New Framerate / Original Framerate. But the playback speed is not determined by the framerate. The framerate is a nominal value that is written to the header of most container formats (but sometimes not). The actual playback speed is completely determined by the timestamps in the file which are not required to perfectly align on framerate boundaries. So New Framerate / Original Framerate is a poor way to specify the desired fraction. Original Framerate is often not known, incorrect, or only an approximation. Video can be variable framerate. The container may have an incorrect framerate written in the header. Or in the case of containers that do not have a framerate in the header, the framerate was approximated by reading a small sample of timestamps and extrapolating.

So the interface for such a filter would have to allow the user to specify the fraction explicitly. There could be "presets" provided for common use cases, but setting the fraction based on framerate just doesn't work.

I would like to comment on your assertion that "Handbrake should be the all-in-one transcoding solution from DVDs and Blurays to video files for different devices". This is explicitly not the case. Our "About HandBrake" gives some detail about what HandBrake is and isn't.
https://handbrake.fr/docs/en/latest/introduction/about.html

We used to have a better article on our wiki that was explicitly about the scope of HandBrake. We need to re-integrate that into our current documentation because the "about" page doesn't really address scope. A well defined scope is important to a project. It helps prevent feature creep and keeps everyone focused or core project priorities.

I'm not saying this request is out of scope. But your statement about what HandBrake should be wanders into areas that are definitely out of scope.

[bradleysepos]

The only time this is really useful is slowing down 25 fps content that was originally sped up from 24 fps content in post production. In my opinion, this is squarely in the scope of an NLE and outside the scope of HandBrake.

[bradleysepos]

@jstebbins See https://github.com/HandBrake/HandBrake-docs/issues/18

[RubenKelevra]

@jstebbins well, Avidemux has a filter which is exactly what I was thinking about.

Well, Avidemux is a awful program, for transcoding files because it's unstable and have no presets and tend to forget stuff you just configured...

BUT, is has a filter, it's just a "enter source framerate, enter destination framerate" field and then it moves the timestamps of the frames by the defined fraction of those two values. As well it alters the Audio-Samplingrate to change the pitch of the audio as well.

I still would love to see this to fix PAL-DVDs with Handbrake.

The thing about NLE is, you have first rip the DVD, than you have to load it in a NLE just to pitch the audio and slowdown the framerate, than you have to save it lossless just to open it again in Handbrake to encode it the way you want... What a time consuming option just to fix the PAL-Framerate.

[hofmand]

I came here looking for the same functionality. It's interesting how About Handbrake says to use video editing software if you want to make changes to the video, yet Handbrake supports cropping, deinterlacing, and other changes to the video.

[RubenKelevra]

@hofmand

Yeah, but they don't care what users might need, unless they encountered that issue themselves in the first place. Pretty much expected american ignorance, I've seen over the past years, just once again.

Hope you find a different solution, for your problem - you won't find it here. 😕