forked from midou/invidious
127 lines
4.2 KiB
Crystal
127 lines
4.2 KiB
Crystal
module Invidious::Videos
|
|
# A `Transcripts` struct encapsulates a sequence of lines that together forms the whole transcript for a given YouTube video.
|
|
# These lines can be categorized into two types: section headings and regular lines representing content from the video.
|
|
struct Transcript
|
|
# Types
|
|
record HeadingLine, start_ms : Time::Span, end_ms : Time::Span, line : String
|
|
record RegularLine, start_ms : Time::Span, end_ms : Time::Span, line : String
|
|
alias TranscriptLine = HeadingLine | RegularLine
|
|
|
|
property lines : Array(TranscriptLine)
|
|
|
|
property language_code : String
|
|
property auto_generated : Bool
|
|
|
|
# User friendly label for the current transcript.
|
|
# Example: "English (auto-generated)"
|
|
property label : String
|
|
|
|
# Initializes a new Transcript struct with the contents and associated metadata describing it
|
|
def initialize(@lines : Array(TranscriptLine), @language_code : String, @auto_generated : Bool, @label : String)
|
|
end
|
|
|
|
# Generates a protobuf string to fetch the requested transcript from YouTube
|
|
def self.generate_param(video_id : String, language_code : String, auto_generated : Bool) : String
|
|
kind = auto_generated ? "asr" : ""
|
|
|
|
object = {
|
|
"1:0:string" => video_id,
|
|
|
|
"2:base64" => {
|
|
"1:string" => kind,
|
|
"2:string" => language_code,
|
|
"3:string" => "",
|
|
},
|
|
|
|
"3:varint" => 1_i64,
|
|
"5:string" => "engagement-panel-searchable-transcript-search-panel",
|
|
"6:varint" => 1_i64,
|
|
"7:varint" => 1_i64,
|
|
"8:varint" => 1_i64,
|
|
}
|
|
|
|
params = object.try { |i| Protodec::Any.cast_json(i) }
|
|
.try { |i| Protodec::Any.from_json(i) }
|
|
.try { |i| Base64.urlsafe_encode(i) }
|
|
.try { |i| URI.encode_www_form(i) }
|
|
|
|
return params
|
|
end
|
|
|
|
# Constructs a Transcripts struct from the initial YouTube response
|
|
def self.from_raw(initial_data : Hash(String, JSON::Any), language_code : String, auto_generated : Bool)
|
|
transcript_panel = initial_data.dig("actions", 0, "updateEngagementPanelAction", "content", "transcriptRenderer",
|
|
"content", "transcriptSearchPanelRenderer")
|
|
|
|
segment_list = transcript_panel.dig("body", "transcriptSegmentListRenderer")
|
|
|
|
if !segment_list["initialSegments"]?
|
|
raise NotFoundException.new("Requested transcript does not exist")
|
|
end
|
|
|
|
# Extract user-friendly label for the current transcript
|
|
|
|
footer_language_menu = transcript_panel.dig?(
|
|
"footer", "transcriptFooterRenderer", "languageMenu", "sortFilterSubMenuRenderer", "subMenuItems"
|
|
)
|
|
|
|
if footer_language_menu
|
|
label = footer_language_menu.as_a.select(&.["selected"].as_bool)[0]["title"].as_s
|
|
else
|
|
label = language_code
|
|
end
|
|
|
|
# Extract transcript lines
|
|
|
|
initial_segments = segment_list["initialSegments"].as_a
|
|
|
|
lines = [] of TranscriptLine
|
|
|
|
initial_segments.each do |line|
|
|
if unpacked_line = line["transcriptSectionHeaderRenderer"]?
|
|
line_type = HeadingLine
|
|
else
|
|
unpacked_line = line["transcriptSegmentRenderer"]
|
|
line_type = RegularLine
|
|
end
|
|
|
|
start_ms = unpacked_line["startMs"].as_s.to_i.millisecond
|
|
end_ms = unpacked_line["endMs"].as_s.to_i.millisecond
|
|
text = extract_text(unpacked_line["snippet"]) || ""
|
|
|
|
lines << line_type.new(start_ms, end_ms, text)
|
|
end
|
|
|
|
return Transcript.new(
|
|
lines: lines,
|
|
language_code: language_code,
|
|
auto_generated: auto_generated,
|
|
label: label
|
|
)
|
|
end
|
|
|
|
# Converts transcript lines to a WebVTT file
|
|
#
|
|
# This is used within Invidious to replace subtitles
|
|
# as to workaround YouTube's rate-limited timedtext endpoint.
|
|
def to_vtt
|
|
settings_field = {
|
|
"Kind" => "captions",
|
|
"Language" => @language_code,
|
|
}
|
|
|
|
vtt = WebVTT.build(settings_field) do |vtt|
|
|
@lines.each do |line|
|
|
# Section headers are excluded from the VTT conversion as to
|
|
# match the regular captions returned from YouTube as much as possible
|
|
next if line.is_a? HeadingLine
|
|
|
|
vtt.cue(line.start_ms, line.end_ms, line.line)
|
|
end
|
|
end
|
|
|
|
return vtt
|
|
end
|
|
end
|
|
end
|