Remove empty_sample_boxes.

[alfredoyang]

Fragmented file can be recognized from stsc, stco, and stts. There is no requirement to keep empty_sample_boxes anymore.

[alfredoyang]

hmm... Travis CI fails at rust nightly build?

[rillian]

The nightly failure is an issue with rustup and the current nightly packaging. See rust-lang/rustup#1062 We can land with nightly failures until that's resolved.

[rillian]

I think moving all this code to a single location is a good idea. And your implementation here is marvelously functional, but the lines are also very long. I tried several different forms, but couldn't find a better way to handle the nested Options. Maybe just break the line before the if guard in the match?

[alfredoyang]

Do you mean this way?

    let mut iter = tracks.iter();
    iter.find(|track| track.track_id == Some(track_id)).map_or(mp4parse_status::BAD_ARG, |track| {
        match (&track.stsc, &track.stco, &track.stts) {
            (&Some(ref stsc), &Some(ref stco), &Some(ref stts))
                if stsc.samples.is_empty() && stco.offsets.is_empty() && stts.samples.is_empty() => (*fragmented) = true as u8,
            _ => {},
        };
        mp4parse_status::OK
    })

[rillian]

yes, that's better I think.

[alfredoyang]

Thanks, PR updated.