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Merge pull request #1216 from canalplus/misc/declareInitSegment
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[Proposal] Add `declareInitSegment` method to the SegmentBuffer abstraction
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@peaBerberian
peaBerberian committed Sep 22, 2023
2 parents 2b928bb + 81ac894 commit 38e85cd
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Showing 14 changed files with 227 additions and 114 deletions.
111 changes: 56 additions & 55 deletions src/core/segment_buffers/implementations/audio_video/audio_video_segment_buffer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -21,11 +21,8 @@ import {
import config from "../../../../config";
import log from "../../../../log";
import { getLoggableSegmentId } from "../../../../manifest";
import areArraysOfNumbersEqual from "../../../../utils/are_arrays_of_numbers_equal";
import assertUnreachable from "../../../../utils/assert_unreachable";
import { toUint8Array } from "../../../../utils/byte_parsing";
import createCancellablePromise from "../../../../utils/create_cancellable_promise";
import hashBuffer from "../../../../utils/hash_buffer";
import noop from "../../../../utils/noop";
import objectAssign from "../../../../utils/object_assign";
import TaskCanceller, {
Expand Down Expand Up @@ -139,20 +136,26 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
private _pendingTask : IAVSBPendingTask | null;

/**
* Keep track of the of the latest init segment pushed in the linked
* SourceBuffer.
* Keep track of the unique identifier of the of the latest init segment
* pushed to the linked SourceBuffer.
*
* This allows to be sure the right initialization segment is pushed before
* any chunk is.
* Such identifiers are first declared through the `declareInitSegment`
* method and the corresponding initialization segment is then pushed through
* the `pushChunk` method.
*
* Keeping track of this allows to be sure the right initialization segment is
* pushed before any chunk is.
*
* `null` if no initialization segment have been pushed to the
* `AudioVideoSegmentBuffer` yet.
*/
private _lastInitSegment : { /** The init segment itself. */
data : Uint8Array;
/** Hash of the initSegment for fast comparison */
hash : number; } |
null;
private _lastInitSegmentUniqueId : string | null;

/**
* Link unique identifiers for initialization segments (as communicated by
* `declareInitSegment`) to the corresponding initialization data.
*/
private _initSegmentsMap : Map<string, BufferSource>;

/**
* @constructor
Expand All @@ -175,8 +178,9 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
this._sourceBuffer = sourceBuffer;
this._queue = [];
this._pendingTask = null;
this._lastInitSegment = null;
this._lastInitSegmentUniqueId = null;
this.codec = codec;
this._initSegmentsMap = new Map();

const onError = this._onPendingTaskError.bind(this);
const reCheck = this._flush.bind(this);
Expand All @@ -199,6 +203,20 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
});
}

public declareInitSegment(
uniqueId : string,
initSegmentData : unknown
) : void {
assertDataIsBufferSource(initSegmentData);
this._initSegmentsMap.set(uniqueId, initSegmentData);
}

public freeInitSegment(
uniqueId : string
) : void {
this._initSegmentsMap.delete(uniqueId);
}

/**
* Push a chunk of the media segment given to the attached SourceBuffer, in a
* FIFO queue.
Expand Down Expand Up @@ -230,12 +248,12 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
infos : IPushChunkInfos<unknown>,
cancellationSignal : CancellationSignal
) : Promise<void> {
assertPushedDataIsBufferSource(infos);
assertDataIsBufferSource(infos.data.chunk);
log.debug("AVSB: receiving order to push data to the SourceBuffer",
this.bufferType,
getLoggableSegmentId(infos.inventoryInfos));
return this._addToQueue({ type: SegmentBufferOperation.Push,
value: infos },
value: infos as IPushChunkInfos<BufferSource> },
cancellationSignal);
}

Expand Down Expand Up @@ -352,7 +370,7 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
* @param {Event} err
*/
private _onPendingTaskError(err : unknown) : void {
this._lastInitSegment = null; // initialize init segment as a security
this._lastInitSegmentUniqueId = null; // initialize init segment as a security
if (this._pendingTask !== null) {
const error = err instanceof Error ?
err :
Expand Down Expand Up @@ -449,7 +467,7 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
const error = e instanceof Error ?
e :
new Error("An unknown error occured when preparing a push operation");
this._lastInitSegment = null; // initialize init segment as a security
this._lastInitSegmentUniqueId = null; // initialize init segment as a security
nextItem.reject(error);
return;
}
Expand Down Expand Up @@ -565,15 +583,17 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
this._sourceBuffer.appendWindowEnd = appendWindow[1];
}

if (data.initSegment !== null &&
(hasUpdatedSourceBufferType || !this._isLastInitSegment(data.initSegment)))
if (data.initSegmentUniqueId !== null &&
(hasUpdatedSourceBufferType ||
!this._isLastInitSegment(data.initSegmentUniqueId)))
{
// Push initialization segment before the media segment
const segmentData = data.initSegment;
const segmentData = this._initSegmentsMap.get(data.initSegmentUniqueId);
if (segmentData === undefined) {
throw new Error("Invalid initialization segment uniqueId");
}
dataToPush.push(segmentData);
const initU8 = toUint8Array(segmentData);
this._lastInitSegment = { data: initU8,
hash: hashBuffer(initU8) };
this._lastInitSegmentUniqueId = data.initSegmentUniqueId;
}

if (data.chunk !== null) {
Expand All @@ -584,56 +604,37 @@ export default class AudioVideoSegmentBuffer extends SegmentBuffer {
}

/**
* Return `true` if the given `segmentData` is the same segment than the last
* Return `true` if the given `uniqueId` is the identifier of the last
* initialization segment pushed to the `AudioVideoSegmentBuffer`.
* @param {BufferSource} segmentData
* @param {string} uniqueId
* @returns {boolean}
*/
private _isLastInitSegment(segmentData : BufferSource) : boolean {
if (this._lastInitSegment === null) {
private _isLastInitSegment(uniqueId : string) : boolean {
if (this._lastInitSegmentUniqueId === null) {
return false;
}
if (this._lastInitSegment.data === segmentData) {
return true;
}
const oldInit = this._lastInitSegment.data;
if (oldInit.byteLength === segmentData.byteLength) {
const newInitU8 = toUint8Array(segmentData);
if (hashBuffer(newInitU8) === this._lastInitSegment.hash &&
areArraysOfNumbersEqual(oldInit, newInitU8))
{
return true;
}
}
return false;
return this._lastInitSegmentUniqueId === uniqueId;
}
}

/**
* Throw if the given input is not in the expected format.
* Allows to enforce runtime type-checking as compile-time type-checking here is
* difficult to enforce.
* @param {Object} pushedData
* @param {Object} data
*/
function assertPushedDataIsBufferSource(
pushedData : IPushChunkInfos<unknown>
) : asserts pushedData is IPushChunkInfos<BufferSource> {
function assertDataIsBufferSource(
data : unknown
) : asserts data is BufferSource {
if (__ENVIRONMENT__.CURRENT_ENV as number === __ENVIRONMENT__.PRODUCTION as number) {
return;
}
const { chunk, initSegment } = pushedData.data;
if (
typeof chunk !== "object" ||
typeof initSegment !== "object" ||
(
chunk !== null &&
!(chunk instanceof ArrayBuffer) &&
!((chunk as ArrayBufferView).buffer instanceof ArrayBuffer)
) ||
typeof data !== "object" ||
(
initSegment !== null &&
!(initSegment instanceof ArrayBuffer) &&
!((initSegment as ArrayBufferView).buffer instanceof ArrayBuffer)
data !== null &&
!(data instanceof ArrayBuffer) &&
!((data as ArrayBufferView).buffer instanceof ArrayBuffer)
)
) {
throw new Error("Invalid data given to the AudioVideoSegmentBuffer");
Expand Down
16 changes: 16 additions & 0 deletions src/core/segment_buffers/implementations/image/image_segment_buffer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,22 @@ export default class ImageSegmentBuffer extends SegmentBuffer {
this._buffered = new ManualTimeRanges();
}

/**
* @param {string} uniqueId
*/
public declareInitSegment(uniqueId : string): void {
log.warn("ISB: Declaring initialization segment for image SegmentBuffer",
uniqueId);
}

/**
* @param {string} uniqueId
*/
public freeInitSegment(uniqueId : string): void {
log.warn("ISB: Freeing initialization segment for image SegmentBuffer",
uniqueId);
}

/**
* @param {Object} data
* @returns {Promise}
Expand Down
16 changes: 16 additions & 0 deletions src/core/segment_buffers/implementations/text/html/html_text_segment_buffer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -137,6 +137,22 @@ export default class HTMLTextSegmentBuffer extends SegmentBuffer {
this.autoRefreshSubtitles(this._canceller.signal);
}

/**
* @param {string} uniqueId
*/
public declareInitSegment(uniqueId : string): void {
log.warn("ISB: Declaring initialization segment for image SegmentBuffer",
uniqueId);
}

/**
* @param {string} uniqueId
*/
public freeInitSegment(uniqueId : string): void {
log.warn("ISB: Freeing initialization segment for image SegmentBuffer",
uniqueId);
}

/**
* Push text segment to the HTMLTextSegmentBuffer.
* @param {Object} infos
Expand Down
16 changes: 16 additions & 0 deletions src/core/segment_buffers/implementations/text/native/native_text_segment_buffer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,22 @@ export default class NativeTextSegmentBuffer extends SegmentBuffer {
this._trackElement = trackElement;
}

/**
* @param {string} uniqueId
*/
public declareInitSegment(uniqueId : string): void {
log.warn("ISB: Declaring initialization segment for image SegmentBuffer",
uniqueId);
}

/**
* @param {string} uniqueId
*/
public freeInitSegment(uniqueId : string): void {
log.warn("ISB: Freeing initialization segment for image SegmentBuffer",
uniqueId);
}

/**
* @param {Object} infos
* @returns {Promise}
Expand Down
20 changes: 16 additions & 4 deletions src/core/segment_buffers/implementations/types.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,13 @@ export abstract class SegmentBuffer {
this._segmentInventory = new SegmentInventory();
}

public abstract declareInitSegment(
uniqueId : string,
initSegmentData : unknown
) : void;

public abstract freeInitSegment(uniqueId : string) : void;

/**
* Push a chunk of the media segment given to the attached buffer, in a
* FIFO queue.
Expand All @@ -96,7 +103,8 @@ export abstract class SegmentBuffer {
* pushed.
*
* Depending on the type of data appended, the pushed chunk might rely on an
* initialization segment, given through the `data.initSegment` property.
* initialization segment, which had to be previously declared through the
* `declareInitSegment` method.
*
* Such initialization segment will be first pushed to the buffer if the
* last pushed segment was associated to another initialization segment.
Expand All @@ -106,7 +114,7 @@ export abstract class SegmentBuffer {
* reference).
*
* If you don't need any initialization segment to push the wanted chunk, you
* can just set `data.initSegment` to `null`.
* can just set the corresponding property to `null`.
*
* You can also only push an initialization segment by setting the
* `data.chunk` argument to null.
Expand Down Expand Up @@ -230,12 +238,16 @@ export type IBufferType = "audio" |
*/
export interface IPushedChunkData<T> {
/**
* The whole initialization segment's data related to the chunk you want to
* The `uniqueId` of the initialization segment linked to the data you want to
* push.
*
* That identifier should previously have been declared through the
* `declareInitSegment` method and not freed.
*
* To set to `null` either if no initialization data is needed, or if you are
* confident that the last pushed one is compatible.
*/
initSegment: T | null;
initSegmentUniqueId : string | null;
/**
* Chunk you want to push.
* This can be the whole decodable segment's data or just a decodable sub-part
Expand Down
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