From 9fc70f3f6d6794e5fc6a8a0b6039818c8ba8298a Mon Sep 17 00:00:00 2001
From: pukkandan <pukkandan.ytdlp@gmail.com>
Date: Sat, 11 Mar 2023 22:46:47 +0530
Subject: [PATCH] [extractor/youtube] Construct fragment list lazily

Building fragment list for all formats take significant time for large videos
---
 yt_dlp/extractor/youtube.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/yt_dlp/extractor/youtube.py b/yt_dlp/extractor/youtube.py
index 3af05e2ed..cc0b5401d 100644
--- a/yt_dlp/extractor/youtube.py
+++ b/yt_dlp/extractor/youtube.py
@@ -3798,11 +3798,11 @@ def _extract_formats_and_subtitles(self, streaming_data, video_id, player_url, l
                     **dct,
                     'format_id': f'{dct["format_id"]}-dashy' if all_formats else dct['format_id'],
                     'protocol': 'http_dash_segments',
-                    'fragments': [{
+                    'fragments': LazyList({
                         'url': update_url_query(dct['url'], {
                             'range': f'{range_start}-{min(range_start + CHUNK_SIZE - 1, dct["filesize"])}'
                         })
-                    } for range_start in range(0, dct['filesize'], CHUNK_SIZE)]
+                    } for range_start in range(0, dct['filesize'], CHUNK_SIZE))
                 }
                 if not all_formats:
                     continue