yuv-rx/dist/y4m.js

Reading videos as Rx Observables of decoded frames

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Y4MHeader = exports.Y4MFrame = exports.Y4MFrameHeader = void 0;
const frame_1 = require("./frame");
function interlacingFromChar(char) {
    switch (char) {
        case 't':
            return 'TopFieldFirst';
        case 'b':
            return 'BottomFieldFirst';
        case 'm':
            return 'Mixed';
        case 'p':
        default:
            return 'Progressive';
    }
}
class Y4MFrameHeader {
}
exports.Y4MFrameHeader = Y4MFrameHeader;
class Y4MFrame {
    constructor(fn, yuv) {
        this.fn = fn;
        this.yuv = yuv;
    }
}
exports.Y4MFrame = Y4MFrame;
class Y4MHeader {
    constructor() {
        this.interlacing = 'Progressive';
        this.aspectRatio = { numerator: 1, denominator: 1 };
        this.colorspace = 'C420mpeg2';
        this.timeScale = -1;
    }
    chromaWidth() {
        if (this.colorspace == 'C444' || this.colorspace == 'C422') {
            return this.width;
        }
        else {
            return Math.ceil(this.width / 2);
        }
    }
    chromaHeight() {
        if (this.colorspace == 'C444') {
            return this.height;
        }
        else {
            return Math.ceil(this.height / 2);
        }
    }
    chromaSize() {
        return this.chromaWidth() * this.chromaHeight();
    }
    lumaSize() {
        return this.width * this.height;
    }
    getFrameSize() {
        return this.lumaSize() + this.chromaSize() * 2;
    }
    static fromString(line) {
        if ('YUV4MPEG2 ' != line.substring(0, 10)) {
            throw new Error('Wrong yuv4mpeg header.');
        }
        const split = line.substring(10).split(' ');
        const header = new Y4MHeader();
        for (const s of split) {
            const key = s.charAt(0);
            const value = s.substring(1);
            switch (key) {
                case 'W':
                    header.width = parseInt(value);
                    break;
                case 'H':
                    header.height = parseInt(value);
                    break;
                case 'F':
                    header.frameRate = (0, frame_1.parseRational)(value);
                    header.timeScale = header.frameRate.numerator;
                    header.videoMediaTimeScale = header.timeScale;
                    break;
                case 'I':
                    header.interlacing = interlacingFromChar(s.charAt(1));
                    break;
                case 'A':
                    header.aspectRatio = (0, frame_1.parseRational)(value);
                    break;
                case 'C':
                    header.colorspace = s;
                    break;
                case 'X':
                    header.comment = value;
                    const vmtsMatch = Y4MHeader.videoMediaTimeScaleRegex.exec(line);
                    if (vmtsMatch != null) {
                        header.videoMediaTimeScale = parseInt(vmtsMatch.groups.ts);
                    }
                    else {
                        const tsMatch = Y4MHeader.timeScaleRegex.exec(line);
                        if (tsMatch != null) {
                            header.timeScale = parseInt(tsMatch.groups.ts);
                        }
                    }
                    break;
            }
        }
        return header;
    }
    toString() {
        return `YUV4MPEG2 W${this.width} H${this.height} F${this.frameRate.numerator}:${this.frameRate.denominator} Ip A${this.aspectRatio.numerator}:${this.aspectRatio.denominator} ${this.colorspace} XYSCSS=420MPEG2`;
    }
}
exports.Y4MHeader = Y4MHeader;
Y4MHeader.timeScaleRegex = /TS=(?<ts>\d+)/;
Y4MHeader.videoMediaTimeScaleRegex = /VMTS=(?<ts>\d+)/;