From 62f918559616138de1cc0ab8f5759f5d714e9287 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Tue, 24 Aug 2021 18:32:26 +0200
Subject: Youtube: load english subtitles when available

---
 src/plugins/Youtube.cpp | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

(limited to 'src/plugins/Youtube.cpp')

diff --git a/src/plugins/Youtube.cpp b/src/plugins/Youtube.cpp
index be405b1..2b2a7ee 100644
--- a/src/plugins/Youtube.cpp
+++ b/src/plugins/Youtube.cpp
@@ -2298,10 +2298,51 @@ namespace QuickMedia {
         return result;
     }
 
+    static void subtitle_url_set_vtt_format(std::string &subtitle_url) {
+        const size_t index = subtitle_url.find("&fmt=");
+        if(index == std::string::npos)
+            return;
+
+        size_t end_index = subtitle_url.find('&');
+        if(end_index == std::string::npos)
+            end_index = subtitle_url.size();
+
+        subtitle_url.replace(index, end_index - index, "&fmt=vtt");
+    }
+
+    static void parse_caption_tracks(const Json::Value &caption_tracks, std::map<std::string, SubtitleData> &subtitle_urls_by_lang_code) {
+        if(!caption_tracks.isArray())
+            return;
+
+        for(const Json::Value &caption_track : caption_tracks) {
+            if(!caption_track.isObject())
+                continue;
+            
+            const Json::Value &base_url_json = caption_track["baseUrl"];
+            const Json::Value &language_code_json = caption_track["languageCode"];
+            if(!base_url_json.isString() || !language_code_json.isString())
+                continue;
+
+            std::string base_url = base_url_json.asString();
+            subtitle_url_set_vtt_format(base_url);
+            std::string language_code = language_code_json.asString();
+
+            std::optional<std::string> title = yt_json_get_text(caption_track, "name");
+            SubtitleData subtitle_data;
+            subtitle_data.url = std::move(base_url);
+            if(title)
+                subtitle_data.title = std::move(title.value());
+            else
+                subtitle_data.title = language_code;
+            subtitle_urls_by_lang_code[std::move(language_code)] = std::move(subtitle_data);
+        }
+    }
+
     PluginResult YoutubeVideoPage::parse_video_response(const Json::Value &json_root, std::string &title, std::string &channel_url, std::vector<MediaChapter> &chapters) {
         livestream_url.clear();
         video_formats.clear();
         audio_formats.clear();
+        subtitle_urls_by_lang_code.clear();
         title.clear();
         channel_url.clear();
         chapters.clear();
@@ -2315,6 +2356,7 @@ namespace QuickMedia {
             if(status_json.isString() && (strcmp(status_json.asCString(), "UNPLAYABLE") == 0 || strcmp(status_json.asCString(), "LOGIN_REQUIRED") == 0)) {
                 const Json::Value &reason_json = playability_status_json["reason"];
                 fprintf(stderr, "Unable to play video, status: %s, reason: %s\n", status_json.asCString(), reason_json.isString() ? reason_json.asCString() : "Unknown");
+                return PluginResult::ERR;
             }
         }
 
@@ -2359,6 +2401,13 @@ namespace QuickMedia {
             }
         }
 
+        const Json::Value &captions_json = json_root["captions"];
+        if(captions_json.isObject()) {
+            const Json::Value &player_captions_tracklist_renderer_json = captions_json["playerCaptionsTracklistRenderer"];
+            if(player_captions_tracklist_renderer_json.isObject())
+                parse_caption_tracks(player_captions_tracklist_renderer_json["captionTracks"], subtitle_urls_by_lang_code);
+        }
+
         const Json::Value &playback_tracing_json = json_root["playbackTracking"];
         if(playback_tracing_json.isObject()) {
             if(playback_url.empty()) {
@@ -2472,6 +2521,12 @@ R"END(
         }
     }
 
+    void YoutubeVideoPage::get_subtitles(SubtitleData &subtitle_data) {
+        auto it = subtitle_urls_by_lang_code.find("en");
+        if(it != subtitle_urls_by_lang_code.end())
+            subtitle_data = it->second;
+    }
+
     static bool parse_cipher_format(const Json::Value &format, YoutubeFormat &youtube_format) {
         std::map<std::string, std::string> cipher_params;
         const Json::Value &cipher_json = format["cipher"];
-- 
cgit v1.2.3