[FEAT] Constant Framerate

[ez-me]

Feature Request

A button/toggle to change the framerate to a constant one, or keep the original (possibly variable) framerate.
This could be done by duplicating and dropping frames (like with ffmpeg -vf "fps=60") or linear interpolation (ffmpeg -vf "framerate=60")

Current Behaviour

Currently, Compressor keeps the same framerate as the original video, with no option to change it.
This could in rare cases lead to audio desynchronization if the app expects constant framerate and finds variable framerate.

Device Info

• Device Model*: Google Pixel 2 XL
• Android Version*: 15
• Device Chipset: Snapdragon 835 (msm8998)
• Device Model Number: G011C (taimen)

[JoshAtticus]

Hi @ez-me, thanks for opening an issue! Compressor does not use ffmpeg, but I can definitely look into this for the next release.

[JoshAtticus]

Reassigning this to low priority and adding to the backburner (medium priority is just the default priority and I forgot to change it)

Media3 actually sucks at converting VFR to CFR, Media3 tries to maintain the presentation timestamps of the original when we set the framerate to a specific level, but when we actually try and transform, Media3 drops frames or duplicates them unpredictably almost 100% of the time.

This is a "Pro" feature for video editors, not for "compress to send to Discord" users. Implementing strict CFR would require a custom GlEffect or FrameDroppingEffect, and if I get the math wrong, the audio will desync worse than before. As I suck at math, someone else can try and implement this for me 🥰