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refactor: readability improvements & fixes
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Remove redundant getAudioTrackGroups
General readability improvements in StreamingInfo.ts
Share response object between `getBitrate` and `getMimeType` as to not make duplicate requests
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@Wykerd
Wykerd committed Aug 12, 2023
1 parent 6b5ba56 commit b329fca
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Showing 3 changed files with 104 additions and 113 deletions.
2 changes: 1 addition & 1 deletion src/utils/DashManifest.tsx
View file
Original file line number Diff line number Diff line change
Expand Up @@ -243,4 +243,4 @@ export function toDash(
storyboards={storyboards}
/>
);
}
}
9 changes: 5 additions & 4 deletions src/utils/DashUtils.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,10 @@ declare global {
}
}

export type DashChild = (DashNode | (DashNode | Promise<DashNode | DashNode[]>) | Promise<DashNode | DashNode[]>);
export interface DashProps {
[key: string]: unknown,
children?: (DashNode | (DashNode | Promise<DashNode | DashNode[]>)[] | Promise<DashNode | DashNode[]>)[]
children?: DashChild[]
}

export interface DashNode {
Expand Down Expand Up @@ -42,7 +43,7 @@ function normalizeTag(tag: string) {
export function createElement(
tagNameOrFunction: string | ((props: DashProps) => DashNode | Promise<DashNode>),
props: { [key: string] : unknown } | null | undefined,
...children: (DashNode | string)[]
...children: DashChild[]
): DashNode | Promise<DashNode> {
const normalizedChildren = children.flat().map((child) => typeof child === 'string' ? createTextElement(child) : child);

Expand Down Expand Up @@ -92,8 +93,8 @@ export async function renderElementToString(element: DashNode): Promise<string>
return `${dom}/>`;
}

export async function renderToString(root: DashNode) {
const dom = await renderElementToString(root);
export async function renderToString(root: DashNode | Promise<DashNode>) {
const dom = await renderElementToString(await root);

return `<?xml version="1.0" encoding="utf-8"?>${dom}`;
}
Expand Down
206 changes: 98 additions & 108 deletions src/utils/StreamingInfo.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -108,7 +108,7 @@ export interface ImageRepresentation {
function getFormatGroupings(formats: Format[]) {
const group_info = new Map<string, Format[]>();

let has_multiple_audio_tracks = false;
const has_multiple_audio_tracks = formats.some((fmt) => !!fmt.audio_track);

for (const format of formats) {
if ((!format.index_range || !format.init_range) && !format.is_type_otf) {
Expand All @@ -120,9 +120,8 @@ function getFormatGroupings(formats: Format[]) {
const just_codec = getStringBetweenStrings(format.mime_type, 'codecs="', '"')?.split('.')[0];

// HDR videos have both SDR and HDR vp9 formats, so we want to stick them in different groups
const color_info = format.color_info ? `${format.color_info.primaries}-${format.color_info.transfer_characteristics}-${format.color_info.matrix_coefficients}` : '';
const color_info = format.color_info ? Object.values(format.color_info).join('-') : '';

has_multiple_audio_tracks = has_multiple_audio_tracks || !!format.audio_track;
const audio_track_id = format.audio_track?.id || '';

const group_id = `${mime_type}-${just_codec}-${color_info}-${audio_track_id}`;
Expand Down Expand Up @@ -161,26 +160,12 @@ function hoistNumberAttributeIfPossible(
}

function hoistAudioChannelsIfPossible(formats: Format[], hoisted: string[]) {
if (formats.length > 1 && new Set(formats.map((format) => format.audio_channels?.toString() || '2')).size === 1) {
if (formats.length > 1 && new Set(formats.map((format) => format.audio_channels || 2)).size === 1) {
hoisted.push('AudioChannelConfiguration');
return formats[0].audio_channels;
}
}

const notrackid = Symbol('ytjs:notrackid');

function getAudioTrackGroups(formats: Format[]) {
const tracks = new Map<string | symbol, Format[]>();
for (const format of formats) {
const tracks_id = !format.audio_track ? notrackid : format.audio_track.id;
if (!tracks.has(tracks_id)) {
tracks.set(tracks_id, []);
}
tracks.get(tracks_id)?.push(format);
}
return Array.from(tracks.values());
}

async function getOTFSegmentTemplate(url: string, actions: Actions): Promise<SegmentTemplate> {
// Fetch the first segment as it contains the segment durations which we need to generate the manifest
const response = await actions.session.http.fetch_function(`${url}&rn=0&sq=0`, {
Expand Down Expand Up @@ -297,7 +282,25 @@ function getAudioRepresentation(
return rep;
}

function getTrackSet(
function getTrackRole(format: Format) {
const { audio_track } = format;

if (!audio_track)
return;

if (audio_track.audio_is_default)
return 'main';

if (format.is_dubbed)
return 'dub';

if (format.is_descriptive)
return 'description';

return 'alternate';
}

function getAudioSet(
formats: Format[],
url_transformer: URLTransformer,
actions?: Actions,
Expand All @@ -314,75 +317,56 @@ function getTrackSet(
codecs: hoistCodecsIfPossible(formats, hoisted),
audio_sample_rate: hoistNumberAttributeIfPossible(formats, 'audio_sample_rate', hoisted),
track_name: audio_track?.display_name,
track_role:
audio_track ?
audio_track.audio_is_default ? 'main' :
first_format.is_dubbed ? 'dub' :
first_format.is_descriptive ? 'description' :
'alternate' : undefined,
track_role: getTrackRole(first_format),
channels: hoistAudioChannelsIfPossible(formats, hoisted),
representations: formats.map((format) => getAudioRepresentation(format, hoisted, url_transformer, actions, player, cpn))
};

return set;
}

function getAudioTrackSets(
formats: Format[],
url_transformer: URLTransformer,
actions?: Actions,
player?: Player,
cpn?: string
) {
const track_groups = getAudioTrackGroups(formats);
const COLOR_PRIMARIES: Record<string, ColorInfo['primaries']> = {
BT709: '1',
BT2020: '9'
};

const COLOR_TRANSFER_CHARACTERISTICS: Record<string, ColorInfo['transfer_characteristics']> = {
BT709: '1',
BT2020_10: '14',
SMPTEST2084: '16',
ARIB_STD_B67: '18'
}

return track_groups.map((tracks) => getTrackSet(tracks, url_transformer, actions, player, cpn));
// This list is incomplete, as the player.js doesn't currently have any code for matrix coefficients,
// So it doesn't have a list like with the other two, so this is just based on what we've seen in responses
const COLOR_MATRIX_COEFFICIENTS: Record<string, ColorInfo['matrix_coefficients']> = {
BT709: '1',
BT2020_NCL: '14'
}

function getColorInfo(format: Format) {
const color_info = format.color_info;
const primaries =
color_info?.primaries ? (
color_info.primaries === 'BT709' ? '1' :
color_info.primaries === 'BT2020' ? '9' :
undefined
) : undefined;
color_info?.primaries ? COLOR_PRIMARIES[color_info.primaries] : undefined;

const transfer_characteristics =
color_info?.transfer_characteristics ? (
color_info?.transfer_characteristics === 'BT709' ? '1' :
color_info?.transfer_characteristics === 'BT2020_10' ? '14' :
color_info?.transfer_characteristics === 'SMPTEST2084' ? '16' :
color_info?.transfer_characteristics === 'ARIB_STD_B67' ? '18' :
undefined
) : undefined;

let matrix_coefficients: '1' | '14' | undefined;
if (color_info?.matrix_coefficients) {

// This list is incomplete, as the player.js doesn't currently have any code for matrix coefficients,
// So it doesn't have a list like with the other two, so this is just based on what we've seen in responses
switch (color_info.matrix_coefficients) {
case 'BT709':
matrix_coefficients = '1';
break;
case 'BT2020_NCL':
matrix_coefficients = '14';
break;
default: {
const url = new URL(format.url as string);

const anonymisedFormat = JSON.parse(JSON.stringify(format));
anonymisedFormat.url = 'REDACTED';
anonymisedFormat.signature_cipher = 'REDACTED';
anonymisedFormat.cipher = 'REDACTED';

console.warn(`YouTube.js toDash(): Unknown matrix coefficients "${color_info.matrix_coefficients}", the DASH manifest is still usuable without this.\n`
+ `Please report it at ${Platform.shim.info.bugs_url} so we can add support for it.\n`
+ `Innertube client: ${url.searchParams.get('c')}\nformat:`, anonymisedFormat);
}
}
}
color_info?.transfer_characteristics ? COLOR_TRANSFER_CHARACTERISTICS[color_info.transfer_characteristics] : undefined;

const matrix_coefficients =
color_info?.matrix_coefficients ? COLOR_MATRIX_COEFFICIENTS[color_info.matrix_coefficients] : undefined;

if (color_info?.matrix_coefficients && !matrix_coefficients) {
const url = new URL(format.url as string);

const anonymisedFormat = JSON.parse(JSON.stringify(format));
anonymisedFormat.url = 'REDACTED';
anonymisedFormat.signature_cipher = 'REDACTED';
anonymisedFormat.cipher = 'REDACTED';

console.warn(`YouTube.js toDash(): Unknown matrix coefficients "${color_info.matrix_coefficients}", the DASH manifest is still usuable without this.\n`
+ `Please report it at ${Platform.shim.info.bugs_url} so we can add support for it.\n`
+ `Innertube client: ${url.searchParams.get('c')}\nformat:`, anonymisedFormat);
}

const info: ColorInfo = {
primaries,
Expand All @@ -407,7 +391,7 @@ function getVideoRepresentation(
width: format.width,
height: format.height,
codecs: !hoisted.includes('codecs') ? getStringBetweenStrings(format.mime_type, 'codecs="', '"') : undefined,
fps: !hoisted.includes('frameRate') ? format.fps : undefined,
fps: !hoisted.includes('fps') ? format.fps : undefined,
segment_info: getSegmentInfo(format, url_transformer, actions, player, cpn)
};

Expand Down Expand Up @@ -442,21 +426,9 @@ function getStoryboardInfo(
const mime_info = new Map<string, StoryboardData[]>();

for (const storyboard of storyboards.boards) {
const extension = new URL(storyboard.template_url).pathname.split('.').at(-1);

let mime_type = '';

switch (extension) {
case 'jpg':
mime_type = 'image/jpeg';
break;
case 'png':
mime_type = 'image/png';
break;
case 'webp':
mime_type = 'image/webp';
break;
}
const extension = new URL(storyboard.template_url).pathname.split('.').pop();

const mime_type = `image/${extension === 'jpg' ? 'jpeg' : extension}`;

if (!mime_info.has(mime_type)) {
mime_info.set(mime_type, []);
Expand All @@ -467,42 +439,57 @@ function getStoryboardInfo(
return mime_info;
}

interface SharedStoryboardResponse {
response?: Promise<Response>
};

async function getStoryboardMimeType(
actions: Actions,
board: StoryboardData,
transform_url: URLTransformer,
probable_mime_type: string
probable_mime_type: string,
shared_response: SharedStoryboardResponse
) {
const url = board.template_url;

const req_url = transform_url(new URL(url.replace('$M', '0')));

const res = await actions.session.http.fetch_function(req_url, {
const res_promise = shared_response.response ? shared_response.response : actions.session.http.fetch_function(req_url, {
method: 'HEAD',
headers: Constants.STREAM_HEADERS
});

shared_response.response = res_promise;

const res = await res_promise;

return res.headers.get('Content-Type') || probable_mime_type;
}

async function getStoryboardBitrate(
actions: Actions,
board: StoryboardData,
transform_url: URLTransformer
shared_response: SharedStoryboardResponse
) {
const url = board.template_url;

const response_promises: Promise<Response>[] = [];

// Set a limit so we don't take forever for long videos
const requestLimit = board.storyboard_count > 10 ? 10 : board.storyboard_count;
for (let i = 0; i < requestLimit; i++) {
const req_url = transform_url(new URL(url.replace('$M', i.toString())));
const request_limit = Math.min(board.storyboard_count, 10);
for (let i = 0; i < request_limit; i++) {
const req_url = new URL(url.replace('$M', i.toString()));

const response_promise = actions.session.http.fetch_function(req_url, {
method: 'HEAD',
headers: Constants.STREAM_HEADERS
});
const response_promise =
i === 0 && shared_response.response ?
shared_response.response :
actions.session.http.fetch_function(req_url, {
method: 'HEAD',
headers: Constants.STREAM_HEADERS
});

if (i === 0)
shared_response.response = response_promise;

response_promises.push(response_promise);
}
Expand All @@ -513,7 +500,7 @@ async function getStoryboardBitrate(
const content_lengths = [];

for (const response of responses) {
content_lengths.push(parseInt(response.headers.get('Content-Length') || '0', 10));
content_lengths.push(parseInt(response.headers.get('Content-Length') || '0'));
}

// This is a rough estimate, so it probably won't reflect that actual peak bitrate
Expand All @@ -527,15 +514,16 @@ function getImageRepresentation(
duration: number,
actions: Actions,
board: StoryboardData,
transform_url: URLTransformer
transform_url: URLTransformer,
shared_response: SharedStoryboardResponse
) {
const url = board.template_url;
const template_url = new URL(url.replace('$M', '$Number$')).toString();
const template_url = new URL(url.replace('$M', '$Number$'));

const rep: ImageRepresentation = {
uid: `thumbnails_${board.thumbnail_width}x${board.thumbnail_height}`,
getBitrate() {
return getStoryboardBitrate(actions, board, transform_url);
return getStoryboardBitrate(actions, board, shared_response);
},
sheet_width: board.thumbnail_width * board.columns,
sheet_height: board.thumbnail_height * board.rows,
Expand All @@ -544,9 +532,9 @@ function getImageRepresentation(
rows: board.rows,
columns: board.columns,
template_duration: duration / board.storyboard_count,
template_url,
template_url: transform_url(template_url).toString(),
getURL(n) {
return template_url.replace('$Number$', n.toString());
return template_url.toString().replace('$Number$', n.toString());
}
};

Expand All @@ -561,12 +549,14 @@ function getImageSets(
) {
const mime_info = getStoryboardInfo(storyboards);

const shared_response: SharedStoryboardResponse = {};

return Array.from(mime_info.entries()).map<ImageSet>(([ type, boards ]) => ({
probable_mime_type: type,
getMimeType() {
return getStoryboardMimeType(actions, boards[0], transform_url, type);
return getStoryboardMimeType(actions, boards[0], transform_url, type, shared_response);
},
representations: boards.map((board) => getImageRepresentation(duration, actions, board, transform_url))
representations: boards.map((board) => getImageRepresentation(duration, actions, board, transform_url, shared_response))
}));
}

Expand Down Expand Up @@ -617,7 +607,7 @@ export function getStreamingInfo(
audio_groups: [] as Format[][]
});

const audio_sets = audio_groups.map((formats) => getAudioTrackSets(formats, url_transformer, actions, player, cpn)).flat();
const audio_sets = audio_groups.map((formats) => getAudioSet(formats, url_transformer, actions, player, cpn));

const video_sets = video_groups.map((formats) => getVideoSet(formats, url_transformer, player, actions, cpn));

Expand Down

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