isomp4: `CodecType` and `extra_data` missing from `avc1` track

When running the following code:

use symphonia_core::{
    formats::{FormatOptions, FormatReader},
    io::MediaSourceStream,
};
use symphonia_format_isomp4::IsoMp4Reader;

fn main() {
    let stream = std::fs::File::open("BigBuckBunny_1s.mp4").unwrap();
    let source = MediaSourceStream::new(Box::new(stream), Default::default());
    let reader = IsoMp4Reader::try_new(source, &FormatOptions::default()).unwrap();
    dbg!(reader.tracks());
}

I get this as (part of) the output:

    Track {
        id: 0,
        codec_params: CodecParameters {
            codec: CodecType(
                0,
            ),
            sample_rate: None,
            time_base: Some(
                TimeBase {
                    numer: 1,
                    denom: 90000,
                },
            ),
            n_frames: Some(
                105000,
            ),
            start_ts: 0,
            sample_format: None,
            bits_per_sample: None,
            bits_per_coded_sample: None,
            channels: None,
            channel_layout: None,
            delay: None,
            padding: None,
            max_frames_per_packet: None,
            packet_data_integrity: false,
            verification_check: None,
            frames_per_block: None,
            extra_data: None,
        },
        language: None,
    },

mp4box.js correctly identifies the codec as avc1.42421f, and the file is also valid otherwise.

The missing extra_data may not be an actual bug, as H.264 has two bitstream formats ("Annex B", and "AVCC"), and in one of them (albeit, the one geared more towards streaming, not storing in files), the extradata is in-band, transmitted as regular data packets (or, samples, or call it whatever you want).

The file for testing: https://github.com/pdeljanov/Symphonia/assets/288816/a92343a0-46f4-411e-9c72-a2328e70d78a

pdeljanov / Symphonia

isomp4: `CodecType` and `extra_data` missing from `avc1` track #271