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chore: Create getTimestampAndDispatchMetadata_function in MediaSourceEngine #5322

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merged 1 commit into from
Jun 16, 2023
Merged

chore: Create getTimestampAndDispatchMetadata_function in MediaSourceEngine #5322

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167 changes: 81 additions & 86 deletions lib/media/media_source_engine.js
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Original file line number Diff line number Diff line change
Expand Up @@ -632,75 +632,29 @@ shaka.media.MediaSourceEngine = class {
}

/**
* Enqueue an operation to append data to the SourceBuffer.
* Start and end times are needed for TextEngine, but not for MediaSource.
* Start and end times may be null for initialization segments; if present
* they are relative to the presentation timeline.
*
* @param {shaka.util.ManifestParserUtils.ContentType} contentType
* @param {!BufferSource} data
* @param {?shaka.media.SegmentReference} reference The segment reference
* we are appending, or null for init segments
* @param {shaka.extern.Stream} stream
* @param {?boolean} hasClosedCaptions True if the buffer contains CEA closed
* captions
* @param {boolean=} seeked True if we just seeked
* @param {boolean=} adaptation True if we just automatically switched active
* variant(s).
* @return {!Promise}
* @param {!string} mimeType
* @param {!number} timestampOffset
* @return {number}
* @private
*/
async appendBuffer(
contentType, data, reference, stream, hasClosedCaptions, seeked = false,
adaptation = false) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;

if (contentType == ContentType.TEXT) {
if (this.sequenceMode_) {
// This won't be known until the first video segment is appended.
const offset = await this.textSequenceModeOffset_;
this.textEngine_.setTimestampOffset(offset);
}
await this.textEngine_.appendBuffer(
data,
reference ? reference.startTime : null,
reference ? reference.endTime : null);
return;
}

const attemptTimestampOffsetCalculation = !this.sequenceMode_ &&
this.manifestType_ == shaka.media.ManifestParser.HLS &&
!this.ignoreManifestTimestampsInSegmentsMode_;

let timestampOffset = this.sourceBuffers_[contentType].timestampOffset;
getTimestampAndDispatchMetadata_(contentType, data, reference, mimeType,
timestampOffset) {
let timestamp = null;

const uint8ArrayData = shaka.util.BufferUtils.toUint8(data);
let mimeType = this.sourceBufferTypes_[contentType];
if (this.transmuxers_[contentType]) {
mimeType = this.transmuxers_[contentType].getOrginalMimeType();
}
if (shaka.util.MimeUtils.RAW_FORMATS.includes(mimeType)) {
const frames = shaka.util.Id3Utils.getID3Frames(uint8ArrayData);
if (frames.length && reference) {
if (attemptTimestampOffsetCalculation) {
const metadataTimestamp = frames.find((frame) => {
return frame.description ===
'com.apple.streaming.transportStreamTimestamp';
});
if (metadataTimestamp && metadataTimestamp.data) {
const calculatedTimestampOffset = reference.startTime -
Math.round(metadataTimestamp.data) / 1000;
const timestampOffsetDifference =
Math.abs(timestampOffset - calculatedTimestampOffset);
if (timestampOffsetDifference >= 0.1 || seeked || adaptation) {
timestampOffset = calculatedTimestampOffset;
this.enqueueOperation_(contentType, () =>
this.abort_(contentType));
this.enqueueOperation_(
contentType,
() => this.setTimestampOffset_(
contentType, timestampOffset));
}
}
const metadataTimestamp = frames.find((frame) => {
return frame.description ===
'com.apple.streaming.transportStreamTimestamp';
});
if (metadataTimestamp && metadataTimestamp.data) {
timestamp = Math.round(metadataTimestamp.data) / 1000;
}
/** @private {shaka.extern.ID3Metadata} */
const metadata = {
Expand All @@ -712,8 +666,7 @@ shaka.media.MediaSourceEngine = class {
};
this.onMetadata_([metadata], /* offset= */ 0, reference.endTime);
}
} else if (attemptTimestampOffsetCalculation &&
mimeType.includes('/mp4') &&
} else if (mimeType.includes('/mp4') &&
reference && reference.timestampOffset == 0 &&
reference.initSegmentReference &&
reference.initSegmentReference.timescale) {
Expand All @@ -738,44 +691,86 @@ shaka.media.MediaSourceEngine = class {
box.parser.stop();
}).parse(data, /* partialOkay= */ true);
if (parsedMedia) {
const calculatedTimestampOffset = reference.startTime - startTime;
const timestampOffsetDifference =
Math.abs(timestampOffset - calculatedTimestampOffset);
if (timestampOffsetDifference >= 0.1 || seeked || adaptation) {
timestampOffset = calculatedTimestampOffset;
this.enqueueOperation_(contentType, () => this.abort_(contentType));
this.enqueueOperation_(
contentType,
() => this.setTimestampOffset_(contentType, timestampOffset));
}
timestamp = startTime;
}
}
} else if (shaka.util.TsParser.probe(uint8ArrayData)) {
const tsParser = new shaka.util.TsParser().parse(uint8ArrayData);
const startTime = tsParser.getStartTime()[contentType];
if (startTime != null) {
const calculatedTimestampOffset = reference.startTime - startTime;
const timestampOffsetDifference =
Math.abs(timestampOffset - calculatedTimestampOffset);
if (timestampOffsetDifference >= 0.1 || seeked || adaptation) {
timestampOffset = calculatedTimestampOffset;
// The SourceBuffer timestampOffset may or may not be set yet,
// so this is the timestamp offset that would eventually compute
// for this segment either way.
if (attemptTimestampOffsetCalculation) {
this.enqueueOperation_(contentType, () => this.abort_(contentType));
this.enqueueOperation_(
contentType,
() => this.setTimestampOffset_(contentType, timestampOffset));
}
}
timestamp = startTime;
}
const metadata = tsParser.getMetadata();
if (metadata.length) {
this.onMetadata_(metadata, timestampOffset,
reference ? reference.endTime : null);
}
}
return timestamp;
}

/**
* Enqueue an operation to append data to the SourceBuffer.
* Start and end times are needed for TextEngine, but not for MediaSource.
* Start and end times may be null for initialization segments; if present
* they are relative to the presentation timeline.
*
* @param {shaka.util.ManifestParserUtils.ContentType} contentType
* @param {!BufferSource} data
* @param {?shaka.media.SegmentReference} reference The segment reference
* we are appending, or null for init segments
* @param {shaka.extern.Stream} stream
* @param {?boolean} hasClosedCaptions True if the buffer contains CEA closed
* captions
* @param {boolean=} seeked True if we just seeked
* @param {boolean=} adaptation True if we just automatically switched active
* variant(s).
* @return {!Promise}
*/
async appendBuffer(
contentType, data, reference, stream, hasClosedCaptions, seeked = false,
adaptation = false) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;

if (contentType == ContentType.TEXT) {
if (this.sequenceMode_) {
// This won't be known until the first video segment is appended.
const offset = await this.textSequenceModeOffset_;
this.textEngine_.setTimestampOffset(offset);
}
await this.textEngine_.appendBuffer(
data,
reference ? reference.startTime : null,
reference ? reference.endTime : null);
return;
}

const attemptTimestampOffsetCalculation = !this.sequenceMode_ &&
this.manifestType_ == shaka.media.ManifestParser.HLS &&
!this.ignoreManifestTimestampsInSegmentsMode_;

let timestampOffset = this.sourceBuffers_[contentType].timestampOffset;

let mimeType = this.sourceBufferTypes_[contentType];
if (this.transmuxers_[contentType]) {
mimeType = this.transmuxers_[contentType].getOrginalMimeType();
}
const timestamp = this.getTimestampAndDispatchMetadata_(
contentType, data, reference, mimeType, timestampOffset);
if (attemptTimestampOffsetCalculation) {
const calculatedTimestampOffset = reference.startTime - timestamp;
const timestampOffsetDifference =
Math.abs(timestampOffset - calculatedTimestampOffset);
if (timestampOffsetDifference >= 0.1 || seeked || adaptation) {
timestampOffset = calculatedTimestampOffset;
if (attemptTimestampOffsetCalculation) {
this.enqueueOperation_(contentType, () => this.abort_(contentType));
this.enqueueOperation_(
contentType,
() => this.setTimestampOffset_(contentType, timestampOffset));
}
}
}
if (hasClosedCaptions && contentType == ContentType.VIDEO) {
if (!this.textEngine_) {
this.reinitText(shaka.util.MimeUtils.CEA608_CLOSED_CAPTION_MIMETYPE,
Expand Down