rx-player
Version:
Canal+ HTML5 Video Player
162 lines (153 loc) • 6.54 kB
text/typescript
/**
* 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 log from "../../log";
import { getNextBoxOffsets } from "../../parsers/containers/isobmff";
import { be4toi, concat } from "../../utils/byte_parsing";
import type { IMediaKeySession } from "../browser_compatibility_types";
import { PSSH_TO_INTEGER } from "./constants";
/**
* Modify "initialization data" sent to a `generateKeyRequest` EME call to
* improve the player's browser compatibility:
*
* 1. some browsers/CDM have problems when the CENC PSSH box is the first
* encountered PSSH box in the initialization data (for the moment just
* Edge was noted with this behavior).
* We found however that it works on every browser when the CENC pssh
* box(es) is/are the last box(es) encountered.
*
* To that end, we move CENC pssh boxes at the end of the initialization
* data in this function.
*
* 2. Some poorly encoded/packaged contents communicate both a CENC with a
* pssh version of 0 and one with a version of 1. We found out that this is
* not always well handled on some devices/browsers (on Edge and some other
* embedded devices that shall remain nameless for now!).
*
* Here this function will filter out CENC pssh with a version different to
* 1 when one(s) with a version of 1 is/are already present.
*
* If the initData is unrecognized or if a CENC PSSH is not found, this function
* throws.
* @param {Uint8Array} initData - Initialization data you want to patch
* @returns {Uint8Array} - Initialization data, patched
*/
export function patchInitData(initData: Uint8Array): Uint8Array {
log.info("Compat: Trying to move CENC PSSH from init data at the end of it.");
let foundCencV1 = false;
let concatenatedCencs = new Uint8Array();
let resInitData = new Uint8Array();
let offset = 0;
while (offset < initData.length) {
if (
initData.length < offset + 8 ||
be4toi(initData, offset + 4) !== PSSH_TO_INTEGER
) {
log.warn("Compat: unrecognized initialization data. Cannot patch it.");
throw new Error("Compat: unrecognized initialization data. Cannot patch it.");
}
const len = be4toi(new Uint8Array(initData), offset);
if (offset + len > initData.length) {
log.warn("Compat: unrecognized initialization data. Cannot patch it.");
throw new Error("Compat: unrecognized initialization data. Cannot patch it.");
}
const currentPSSH = initData.subarray(offset, offset + len);
// yep
if (
initData[offset + 12] === 0x10 &&
initData[offset + 13] === 0x77 &&
initData[offset + 14] === 0xef &&
initData[offset + 15] === 0xec &&
initData[offset + 16] === 0xc0 &&
initData[offset + 17] === 0xb2 &&
initData[offset + 18] === 0x4d &&
initData[offset + 19] === 0x02 &&
initData[offset + 20] === 0xac &&
initData[offset + 21] === 0xe3 &&
initData[offset + 22] === 0x3c &&
initData[offset + 23] === 0x1e &&
initData[offset + 24] === 0x52 &&
initData[offset + 25] === 0xe2 &&
initData[offset + 26] === 0xfb &&
initData[offset + 27] === 0x4b
) {
const cencOffsets = getNextBoxOffsets(currentPSSH);
const version = cencOffsets === null ? undefined : currentPSSH[cencOffsets[1]];
log.info("Compat: CENC PSSH found with version", version);
if (version === undefined) {
log.warn("Compat: could not read version of CENC PSSH");
} else if (foundCencV1 === (version === 1)) {
// Either `concatenatedCencs` only contains v1 or does not contain any
concatenatedCencs = concat(concatenatedCencs, currentPSSH);
} else if (version === 1) {
log.warn(
"Compat: cenc version 1 encountered, " + "removing every other cenc pssh box.",
);
concatenatedCencs = currentPSSH;
foundCencV1 = true;
} else {
log.warn("Compat: filtering out cenc pssh box with wrong version", version);
}
} else {
resInitData = concat(resInitData, currentPSSH);
}
offset += len;
}
if (offset !== initData.length) {
log.warn("Compat: unrecognized initialization data. Cannot patch it.");
throw new Error("Compat: unrecognized initialization data. Cannot patch it.");
}
return concat(resInitData, concatenatedCencs);
}
/**
* Generate a request from session.
* @param {MediaKeySession} session - MediaKeySession on which the request will
* be done.
* @param {string} initializationDataType - Initialization data type given e.g.
* by the "encrypted" event for the corresponding request.
* @param {Uint8Array} initializationData - Initialization data given e.g. by
* the "encrypted" event for the corresponding request.
* @returns {Promise} - Emit when done. Errors if fails.
*/
export default function generateKeyRequest(
session: IMediaKeySession,
initializationDataType: string | undefined,
initializationData: Uint8Array,
): Promise<unknown> {
log.debug("Compat: Calling generateRequest on the MediaKeySession");
let patchedInit: Uint8Array;
try {
patchedInit = patchInitData(initializationData);
} catch (_e) {
patchedInit = initializationData;
}
const initDataType = initializationDataType ?? "";
return session.generateRequest(initDataType, patchedInit).catch((error) => {
if (initDataType !== "" || !(error instanceof TypeError)) {
throw error;
}
// On newer EME versions of the specification, the initialization data
// type given to generateRequest cannot be an empty string (it returns
// a rejected promise with a TypeError in that case).
// Retry with a default "cenc" value for initialization data type if
// we're in that condition.
log.warn(
"Compat: error while calling `generateRequest` with an empty " +
'initialization data type. Retrying with a default "cenc" value.',
error,
);
return session.generateRequest("cenc", patchedInit);
});
}