"annexb"

[jxors]

Hi! Filing this issue because of the comment:

/// Please file an issue if you know what this does, because I have no idea.
pub fn annexb(mut self, annexb: bool) -> Self {

This repo doesn't seem very active anymore, but maybe this helps someone else struggling with the same thing as me.

The way I understand it, "Annex B" start codes are a way to be able to seek to the next/previous NAL unit from anywhere in a stream. The mp4 container does not use Annex B start codes, so if you're trying to use this library in combination with for example the mp4 crate, you need to make sure to turn off the Annex B start codes, because they're enabled by default. For example:

let mut encoder =
    Setup::preset(Preset::Medium, Tune::None, false, true)
        .annexb(false)
        .build(Colorspace::I420, WIDTH as _, HEIGHT as _)
        .unwrap();

(also, make sure to crop off the first 4 bytes of the SPS and PPS headers before passing them to mp4)