/* * libmedia mp4 tfhd box parser * * 版权所有 (C) 2024 赵高兴 * Copyright (C) 2024 Gaoxing Zhao * * 此文件是 libmedia 的一部分 * This file is part of libmedia. * * libmedia 是自由软件;您可以根据 GNU Lesser General Public License(GNU LGPL)3.1 * 或任何其更新的版本条款重新分发或修改它 * libmedia is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 3.1 of the License, or (at your option) any later version. * * libmedia 希望能够为您提供帮助,但不提供任何明示或暗示的担保,包括但不限于适销性或特定用途的保证 * 您应自行承担使用 libmedia 的风险,并且需要遵守 GNU Lesser General Public License 中的条款和条件。 * libmedia is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * */ import type { Atom, IsobmffContext } from '../type' import { TFHDFlags } from '../boxType' import { logger } from '@libmedia/common' import { type IOReader } from '@libmedia/common/io' import { type AVStream } from '@libmedia/avutil' export default async function read(ioReader: IOReader, stream: AVStream, atom: Atom, isobmffContext: IsobmffContext) { const now = ioReader.getPos() const version = await ioReader.readUint8() const flags = await ioReader.readUint24() const trackId = await ioReader.readUint32() const track = isobmffContext.currentFragment.currentTrack track.trackId = trackId if (track) { if (flags & TFHDFlags.BASE_DATA_OFFSET) { track.baseDataOffset = await ioReader.readUint64() } if (flags & TFHDFlags.SAMPLE_DESCRIPTION) { await ioReader.skip(4) } if (flags & TFHDFlags.SAMPLE_DURATION) { track.defaultSampleDuration = await ioReader.readUint32() } if (flags & TFHDFlags.SAMPLE_SIZE) { track.defaultSampleSize = await ioReader.readUint32() } if (flags & TFHDFlags.SAMPLE_FLAGS) { track.defaultSampleFlags = await ioReader.readUint32() } if (flags & TFHDFlags.DEFAULT_BASE_IS_MOOF) { track.baseIsMoof = true } } const remainingLength = atom.size - Number(ioReader.getPos() - now) if (remainingLength > 0) { await ioReader.skip(remainingLength) } else if (remainingLength < 0) { logger.error(`read vpcc error, size: ${atom.size}, read: ${atom.size - remainingLength}`) } }