rx-player/src/transports/local/segment_parser.ts

Canal+ HTML5 Video Player

/**
 * Copyright 2015 CANAL+ Group
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { getMDHDTimescale, takePSSHOut } from "../../parsers/containers/isobmff";
import { getKeyIdFromInitSegment } from "../../parsers/containers/isobmff/utils";
import { getTimeCodeScale } from "../../parsers/containers/matroska";
import type {
  IProtectionDataInfo,
  ISegmentContext,
  ISegmentParserParsedInitChunk,
  ISegmentParserParsedMediaChunk,
} from "../types";
import getISOBMFFTimingInfos from "../utils/get_isobmff_timing_infos";
import inferSegmentContainer from "../utils/infer_segment_container";

export default function segmentParser(
  loadedSegment: {
    data: ArrayBuffer | Uint8Array<ArrayBuffer> | null;
    isChunked: boolean;
  },
  context: ISegmentContext,
  initTimescale: number | undefined,
):
  | ISegmentParserParsedInitChunk<ArrayBuffer | Uint8Array<ArrayBuffer> | null>
  | ISegmentParserParsedMediaChunk<ArrayBuffer | Uint8Array<ArrayBuffer> | null> {
  const { segment, periodStart, periodEnd } = context;
  const { data } = loadedSegment;
  const appendWindow: [number, number | undefined] = [periodStart, periodEnd];

  if (data === null) {
    if (segment.isInit) {
      return {
        segmentType: "init",
        initializationData: null,
        initializationDataSize: 0,
        protectionData: [],
        initTimescale: undefined,
      };
    }
    return {
      segmentType: "media",
      chunkData: null,
      chunkSize: 0,
      chunkInfos: null,
      chunkOffset: 0,
      protectionData: [],
      appendWindow,
    };
  }

  const chunkData = new Uint8Array(data);
  const containerType = inferSegmentContainer(context.type, context.mimeType);

  // TODO take a look to check if this is an ISOBMFF/webm?
  const seemsToBeMP4 = containerType === "mp4" || containerType === undefined;
  const protectionData: IProtectionDataInfo[] = [];
  if (seemsToBeMP4) {
    const psshInfo = takePSSHOut(chunkData);
    let keyId;
    if (segment.isInit) {
      keyId = getKeyIdFromInitSegment(chunkData) ?? undefined;
    }
    if (psshInfo.length > 0 || keyId !== undefined) {
      protectionData.push({ initDataType: "cenc", keyId, initData: psshInfo });
    }
  }

  if (segment.isInit) {
    const timescale =
      containerType === "webm"
        ? getTimeCodeScale(chunkData, 0)
        : // assume ISOBMFF-compliance
          getMDHDTimescale(chunkData);
    return {
      segmentType: "init",
      initializationData: chunkData,
      initializationDataSize: 0,
      initTimescale: timescale ?? undefined,
      protectionData,
    };
  }

  const chunkInfos = seemsToBeMP4
    ? getISOBMFFTimingInfos(chunkData, false, segment, initTimescale)
    : null; // TODO extract time info from webm
  const chunkOffset = segment.timestampOffset ?? 0;
  return {
    segmentType: "media",
    chunkData,
    chunkSize: chunkData.length,
    chunkInfos,
    chunkOffset,
    protectionData,
    appendWindow,
  };
}