mp4filechecker/es/index.js

Check details of an mp4 file, e.g. to determine if transcoding is required

import * as Mp4Box from 'mp4box';
export const DEFAULT_OPTIONS = {
    maxWidth: 1280,
    maxHeight: 720,
    supportedMimeTypes: [
        'video/mp4'
    ],
    supportedVideoCodecs: [
        /^avc1\.42e0/,
        /^avc1\.4d40/,
        /^avc1\.6400/
    ],
    supportedAudioCodecs: [
        'mp4a.40.2',
        'mp4a.40.5'
    ]
};
const loadBuffer = (blob)=>new Promise(function(resolve, reject) {
        const fileReader = new FileReader();
        fileReader.onload = function(evt) {
            if (!evt.target) {
                reject(new Error('File could not be read'));
            } else if (evt.target.error) {
                reject(evt.target.error);
            } else {
                resolve(evt.target.result);
            }
        };
        fileReader.readAsArrayBuffer(blob);
    });
async function* loadChunks(file, chunkSize = 64 * 1024) {
    const fileSize = file.size;
    let offset = 0;
    while(offset <= fileSize){
        const chunkBlob = file.slice(offset, chunkSize + offset);
        const chunkData = await loadBuffer(chunkBlob);
        chunkData.fileStart = offset;
        yield chunkData;
        offset += chunkData.byteLength;
    }
}
const matchesOne = (candidateValue, testValues)=>{
    return testValues.some((testCase)=>{
        if (testCase instanceof RegExp) {
            return testCase.test(candidateValue);
        } else {
            return candidateValue === testCase;
        }
    });
};
const isMatch = (info, options)=>{
    const tracks = info.tracks;
    return tracks.every((track)=>{
        if (track.type === 'video') {
            const isSupportedCodec = matchesOne(track.codec, options.supportedVideoCodecs);
            const isSupportedWidth = track.video.width <= options.maxWidth;
            const isSupportedHeight = track.video.height <= options.maxHeight;
            return isSupportedCodec && isSupportedWidth && isSupportedHeight;
        } else if (track.type === 'audio') {
            return matchesOne(track.codec, options.supportedAudioCodecs);
        } else {
            return true;
        }
    });
};
/**
 * Checks whether an mp4 video file matches the provided criteria.
 *
 * @param file The provided mp4 video as a File or Blob
 * @param options The video/audio track options which need to match
 *
 * @returns Promise.resolved(true) when the mp4 file matches the criteria provided in options, Promise.resolved(false) otherwise.
 */ export const checkMp4File = async (file, options = DEFAULT_OPTIONS)=>{
    if (!file || !matchesOne(file.type, options.supportedMimeTypes)) {
        return false;
    }
    const box = Mp4Box.createFile();
    let result = null;
    box.onReady = (info)=>{
        result = info;
    };
    for await (const chunk of loadChunks(file)){
        box.appendBuffer(chunk);
        if (result) {
            break;
        }
    }
    if (result === null) {
        return false;
    } else {
        return isMatch(result, options);
    }
};