rx-player
Version:
Canal+ HTML5 Video Player
270 lines (269 loc) • 9.47 kB
JavaScript
"use strict";
/**
* 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.
*/
var __read = (this && this.__read) || function (o, n) {
var m = typeof Symbol === "function" && o[Symbol.iterator];
if (!m) return o;
var i = m.call(o), r, ar = [], e;
try {
while ((n === void 0 || n-- > 0) && !(r = i.next()).done) ar.push(r.value);
}
catch (error) { e = { error: error }; }
finally {
try {
if (r && !r.done && (m = i["return"])) m.call(i);
}
finally { if (e) throw e.error; }
}
return ar;
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.getTimeCodeScale = getTimeCodeScale;
exports.getSegmentsFromCues = getSegmentsFromCues;
var log_1 = require("../../../log");
var SEGMENT_ID = 0x18538067;
var INFO_ID = 0x1549a966;
var TIMECODESCALE_ID = 0x2ad7b1;
var DURATION_ID = 0x4489;
var CUES_ID = 0x1c53bb6b;
var CUE_POINT_ID = 0xbb;
var CUE_TIME_ID = 0xb3;
var CUE_TRACK_POSITIONS_ID = 0xb7;
var CUE_CLUSTER_POSITIONS_ID = 0xf1;
/**
* Find the offsets of the value linked to the given element ID.
* @param {number} elementID - ID for the searched element.
* @param {Array.<number>} parents - eventual IDs of the parent elements. From
* top level to lower level (from the furthest to the closest).
* @param {Uint8Array} buffer - buffer where the ID will be searched
* @param {Array.<number>} range - start and end offsets in the buffer where the
* ID will be searched.
* @returns {Array.<number>|null}
*/
function findNextElement(elementID, parents, buffer, _a) {
var _b = __read(_a, 2), initialOffset = _b[0], maxOffset = _b[1];
var currentOffset = initialOffset;
while (currentOffset < maxOffset) {
var parsedID = getEBMLID(buffer, currentOffset);
if (parsedID === null) {
return null;
}
var ebmlTagID = parsedID.value, ebmlTagLength = parsedID.length;
var sizeOffset = currentOffset + ebmlTagLength;
var parsedValue = getEBMLValue(buffer, sizeOffset);
if (parsedValue === null) {
return null;
}
var valueLengthLength = parsedValue.length, valueLength = parsedValue.value;
var valueOffset = sizeOffset + valueLengthLength;
var valueEndOffset = valueOffset + valueLength;
if (ebmlTagID === elementID) {
return [valueOffset, valueEndOffset];
}
else if (parents.length > 0) {
for (var i = 0; i < parents.length; i++) {
if (ebmlTagID === parents[i]) {
var newParents = parents.slice(i + 1, parents.length);
return findNextElement(elementID, newParents, buffer, [
valueOffset,
valueEndOffset,
]);
}
}
}
currentOffset = valueEndOffset;
}
return null;
}
/**
* Return the timecode scale (basically timescale) of the whole file.
* @param {Uint8Array} buffer
* @param {number} initialOffset
* @returns {number|null}
*/
function getTimeCodeScale(buffer, initialOffset) {
var timeCodeScaleOffsets = findNextElement(TIMECODESCALE_ID, [SEGMENT_ID, INFO_ID], buffer, [initialOffset, buffer.length]);
if (timeCodeScaleOffsets === null) {
return null;
}
var length = timeCodeScaleOffsets[1] - timeCodeScaleOffsets[0];
return 1e9 / bytesToNumber(buffer, timeCodeScaleOffsets[0], length);
}
/**
* Return the duration of the concerned media.
* @param {Uint8Array} buffer
* @param {number} initialOffset
* @returns {number|null}
*/
function getDuration(buffer, initialOffset) {
var timeCodeScaleOffsets = findNextElement(DURATION_ID, [SEGMENT_ID, INFO_ID], buffer, [initialOffset, buffer.length]);
if (timeCodeScaleOffsets === null) {
return null;
}
var length = timeCodeScaleOffsets[1] - timeCodeScaleOffsets[0];
if (length === 4) {
return get_IEEE754_32Bits(buffer, timeCodeScaleOffsets[0]);
}
else if (length === 8) {
return get_IEEE754_64Bits(buffer, timeCodeScaleOffsets[0]);
}
return null;
}
/**
* @param {Uint8Array} buffer
* @param {number} initialOffset
* @returns {Array.<Object>|null}
*/
function getSegmentsFromCues(buffer, initialOffset) {
var segmentRange = findNextElement(SEGMENT_ID, [], buffer, [
initialOffset,
buffer.length,
]);
if (segmentRange === null) {
return null;
}
var _a = __read(segmentRange, 2), segmentRangeStart = _a[0], segmentRangeEnd = _a[1];
var timescale = getTimeCodeScale(buffer, segmentRangeStart);
if (timescale === null) {
return null;
}
var duration = getDuration(buffer, segmentRangeStart);
if (duration === null) {
return null;
}
var cuesRange = findNextElement(CUES_ID, [], buffer, [
segmentRangeStart,
segmentRangeEnd,
]);
if (cuesRange === null) {
return null;
}
var rawInfos = [];
var currentOffset = cuesRange[0];
while (currentOffset < cuesRange[1]) {
var cuePointRange = findNextElement(CUE_POINT_ID, [], buffer, [
currentOffset,
cuesRange[1],
]);
if (cuePointRange === null) {
break;
}
var cueTimeRange = findNextElement(CUE_TIME_ID, [], buffer, [
cuePointRange[0],
cuePointRange[1],
]);
if (cueTimeRange === null) {
return null;
}
var time = bytesToNumber(buffer, cueTimeRange[0], cueTimeRange[1] - cueTimeRange[0]);
var cueOffsetRange = findNextElement(CUE_CLUSTER_POSITIONS_ID, [CUE_TRACK_POSITIONS_ID], buffer, [cuePointRange[0], cuePointRange[1]]);
if (cueOffsetRange === null) {
return null;
}
var rangeStart = bytesToNumber(buffer, cueOffsetRange[0], cueOffsetRange[1] - cueOffsetRange[0]) +
segmentRangeStart;
rawInfos.push({ time: time, rangeStart: rangeStart });
currentOffset = cuePointRange[1];
}
var segments = [];
for (var i = 0; i < rawInfos.length; i++) {
var currentSegment = rawInfos[i];
if (i === rawInfos.length - 1) {
segments.push({
time: currentSegment.time,
timescale: timescale,
duration: i === 0 ? duration : duration - currentSegment.time,
range: [currentSegment.rangeStart, Infinity],
});
}
else {
segments.push({
time: currentSegment.time,
timescale: timescale,
duration: rawInfos[i + 1].time - currentSegment.time,
range: [currentSegment.rangeStart, rawInfos[i + 1].rangeStart - 1],
});
}
}
return segments;
}
function getLength(buffer, offset) {
for (var length_1 = 1; length_1 <= 8; length_1++) {
if (buffer[offset] >= Math.pow(2, 8 - length_1)) {
return length_1;
}
}
return undefined;
}
function getEBMLID(buffer, offset) {
var length = getLength(buffer, offset);
if (length === undefined) {
log_1.default.warn("webm: unrepresentable length");
return null;
}
if (offset + length > buffer.length) {
log_1.default.warn("webm: impossible length");
return null;
}
var value = 0;
for (var i = 0; i < length; i++) {
value = buffer[offset + i] * Math.pow(2, (length - i - 1) * 8) + value;
}
return { length: length, value: value };
}
function getEBMLValue(buffer, offset) {
var length = getLength(buffer, offset);
if (length === undefined) {
log_1.default.warn("webm: unrepresentable length");
return null;
}
if (offset + length > buffer.length) {
log_1.default.warn("webm: impossible length");
return null;
}
var value = (buffer[offset] & ((1 << (8 - length)) - 1)) * Math.pow(2, (length - 1) * 8);
for (var i = 1; i < length; i++) {
value = buffer[offset + i] * Math.pow(2, (length - i - 1) * 8) + value;
}
return { length: length, value: value };
}
/**
* Convert a IEEE754 32 bits floating number as an Uint8Array into its
* corresponding Number.
* @param {Uint8Array} buffer
* @param {number} offset
* @returns {number}
*/
function get_IEEE754_32Bits(buffer, offset) {
return new DataView(buffer.buffer).getFloat32(offset);
}
/**
* Convert a IEEE754 64 bits floating number as an Uint8Array into its
* corresponding Number.
* @param {Uint8Array} buffer
* @param {number} offset
* @returns {number}
*/
function get_IEEE754_64Bits(buffer, offset) {
return new DataView(buffer.buffer).getFloat64(offset);
}
function bytesToNumber(buffer, offset, length) {
var value = 0;
for (var i = 0; i < length; i++) {
value = buffer[offset + i] * Math.pow(2, (length - i - 1) * 8) + value;
}
return value;
}