Parse avcc Box ?

[LuoZijun]

Hi,

Does this library now support parsing avcc box?

I wrote some code to convert the MP4 (H264) file into a H264 stream file.

Since the avcc box parsing is not currently supported,
I cannot extract SPS NAL and PPS NAL from mp4parse::track.

Code: https://gist.github.com/LuoZijun/3e727fd5d337e2e780ba7d68c7bef618#file-mp4_video_samples_to_h264-rs-L259

Raw H.264 Stream:

SEI NAL | SPS NAL | PPS NAL | IDR NAL ....

[kinetiknz]

Does this library now support parsing avcc box?

Not at the moment. It just copies the box contents into the codec_specific field of SampleEntry, which is available via Track.data.

It'd be nice if the library was more complete, but anything currently missing is either handled by other (C++) code inside Gecko or unused by Gecko, so there are no immediate plans to extend the parser. Contributions with tests are welcome, of course.

[LuoZijun]

@kinetiknz

Line: https://github.com/mozilla/mp4parse-rust/blob/master/mp4parse/src/lib.rs#L1867-L1868

#[derive(Debug)]
struct AVCVideoConfigurationRecord {
    version: u8,
    profile: u8,
    compatibility: u8,
    level: u8,
    // indicates the length in bytes of the length field in an AVC video access unit used indicate the length of each NAL unit. 
    length_size_minus_one: u8,
    sps: Vec<Vec<u8>>,
    pps: Vec<Vec<u8>>,
}

fn parse_avc_config(data: &[u8]) -> AVCVideoConfigurationRecord {
    let version = data[0];
    let avc_profile = data[1];
    let avc_compatibility = data[2];
    let avc_level = data[3];
    let NALULengthSizeMinusOne = data[4] & 0b00000011;
    let number_of_SPS_NALUs = data[5] & 0b00011111;
    let mut i: usize = 6;

    let sps_elems = (0..number_of_SPS_NALUs)
        .map(|_|{
            let sps_size = u16::from_be_bytes([data[i], data[i+1]]) as usize;
            i += 2;
            let sps: Vec<u8> = data[i..i+sps_size].to_vec();
            i += sps_size;
            sps
        })
        .collect::<Vec<Vec<u8>>>();

    let number_of_PPS_NALUs = data[i];
    i += 1;

    let pps_elems = (0..number_of_PPS_NALUs)
        .map(|_|{
            let pps_size = u16::from_be_bytes([data[i], data[i+1]]) as usize;
            i += 2;
            let sps: Vec<u8> = data[i..i+pps_size].to_vec();
            i += pps_size;
            sps
        })
        .collect::<Vec<Vec<u8>>>();

    assert_eq!(version, 1);

    AVCVideoConfigurationRecord {
        version,
        profile: avc_profile,
        compatibility: avc_compatibility,
        level: avc_level,
        length_size_minus_one: NALULengthSizeMinusOne,
        sps: sps_elems,
        pps: pps_elems,
    }
}

this work for me.

but change this line is difficult for me: https://github.com/mozilla/mp4parse-rust/blob/master/mp4parse_capi/src/lib.rs#L640