hjplayer/src/Utils/media-info.ts

hjplayer, a HTML5 Player, can play flv and hls by Media Source Extension, based on typescript;

import { AudioMediaData } from '../Codecs/FLVCodec/interface';

class MediaInfo {
    mimeType: string | null

    duration: number | null | undefined

    hasAudio: boolean | null | undefined

    hasVideo: boolean | null | undefined

    audioCodec: string | null | undefined

    videoCodec: string | null | undefined

    audioDataRate: number | null

    videoDataRate: number | null

    audioSampleRate: number | null | undefined

    audioChannelCount: number | null | undefined

    width: number | null | undefined

    height: number | null | undefined

    fps: number | null

    profile: string | null | undefined

    level: string | null | undefined

    refFrames: number | null

    chromaFormat: string | null

    sarNum: number | null

    sarDen: number | null

    metadata: AudioMediaData | null

    segments: MediaInfo[] | null

    segmentCount: number | null

    hasKeyframesIndex: boolean | null

    keyframesIndex: {
        times: number[]
        filepositions: number[]
    } | null

    constructor() {
        this.mimeType = null;
        this.duration = null;

        this.hasAudio = null;
        this.hasVideo = null;
        this.audioCodec = null;
        this.videoCodec = null;
        this.audioDataRate = null;
        this.videoDataRate = null;

        this.audioSampleRate = null;
        this.audioChannelCount = null;

        this.width = null;
        this.height = null;
        this.fps = null;
        this.profile = null;
        this.level = null;
        this.refFrames = null;
        this.chromaFormat = null;
        this.sarNum = null;
        this.sarDen = null;

        this.metadata = null;
        this.segments = null; // MediaInfo[]
        this.segmentCount = null;
        this.hasKeyframesIndex = null;
        this.keyframesIndex = null;
    }

    isComplete() {
        const audioInfoComplete = this.hasAudio === false
            || (this.hasAudio === true
                && this.audioCodec != null
                && this.audioSampleRate != null
                && this.audioChannelCount != null);

        const videoInfoComplete = this.hasVideo === false
            || (this.hasVideo === true
                && this.videoCodec != null
                && this.width != null
                && this.height != null
                && this.fps != null
                && this.profile != null
                && this.level != null
                && this.refFrames != null
                && this.chromaFormat != null
                && this.sarNum != null
                && this.sarDen != null);

        // keyframesIndex may not be present
        return (
            this.mimeType != null
            && this.duration != null
            && this.metadata != null
            && this.hasKeyframesIndex != null
            && audioInfoComplete
            && videoInfoComplete
        );
    }

    isSeekable() {
        return this.hasKeyframesIndex === true;
    }

    getNearestKeyframe(milliseconds: number) {
        if(this.keyframesIndex == null) {
            return null;
        }

        const table = this.keyframesIndex;
        const keyframeIdx = this._search(table.times, milliseconds);

        return {
            index: keyframeIdx,
            milliseconds: table.times[keyframeIdx],
            fileposition: table.filepositions[keyframeIdx]
        };
    }

    _search(list: number[], value: number) {
        let idx = 0;

        const last = list.length - 1;
        let mid = 0;
        let lbound = 0;
        let ubound = last;

        if(value < list[0]) {
            idx = 0;
            lbound = ubound + 1; // skip search
        }

        while(lbound <= ubound) {
            mid = lbound + Math.floor((ubound - lbound) / 2);
            if(mid === last || (value >= list[mid] && value < list[mid + 1])) {
                idx = mid;
                break;
            } else if(list[mid] < value) {
                lbound = mid + 1;
            } else {
                ubound = mid - 1;
            }
        }

        return idx;
    }
}

export default MediaInfo;