YouTube Downloader 1.1.0
========================

Saves a YouTube video to your PC as an MP4. Nothing happens until you
click a button.

INSTALL
1. Download YouTubeDownloader-Setup-1.1.0.exe and double-click it.
2. Windows asks for permission (the administrator prompt). Click Yes.
   The program installs into Program Files, the same as other programs.
3. Click through Setup. Near the end a window shows each step while it
   sets up the program's own Python and download engine. This takes a
   minute or two the first time.
   If FFmpeg, Deno or uv are missing, Setup adds them with winget, which
   comes with Windows 10 and 11.
4. Open YouTube Downloader from the desktop icon or the Start menu.

Setup always makes a desktop icon and a Start menu folder (YouTube
Downloader, Read me, Uninstall). It does not open the program by itself
unless you tick "Open YouTube Downloader now" on the last page.
Running Setup again repairs or updates the install. It never deletes
anything.

USE
1. Copy a video's address from YouTube. Click Paste, then Look Up.
2. Pick a quality. Each line says what it plays in:
     H.264  plays everywhere, every editor (AVPrep2, AVPrep3, Premiere,
            phones). YouTube offers it up to 1080p.
     VP9 / AV1  anything above 1080p. Needs a modern player or editor.
   The size shown is YouTube's own estimate.
3. Choose the Save to folder once. It is remembered.
4. Click Download. Stop works at any time; the unfinished piece stays in
   the folder, and clicking Download again with the same quality carries
   on from where it stopped.
5. Play or Show in Folder when it finishes.

A file never replaces an existing one. A second copy of the same video
is saved as "Title (2).mp4".

ABOUT THE SEPARATE PIECES
For anything above 360p, YouTube sends the picture and the sound as two
files, and FFmpeg joins them into one MP4. By default the download engine
removes those two working pieces after a successful join, the same as
every yt-dlp front end. Tick "Keep the separate picture and sound files"
before clicking Download if you want them kept.

WHEN DOWNLOADS START FAILING
YouTube changes its site often. Click Update Engine, close the window,
open it again, and try again. That fixes most failures. Show Details
displays the engine's own messages. Update Engine does not need the
administrator prompt: each update goes into its own dated folder under
%LOCALAPPDATA%\YouTube Downloader\engine, and the program uses the newest
one. The bottom line says "(updated copy)" when it is using one.

The bottom line of the window shows whether FFmpeg and Deno were found.
Deno runs YouTube's player code; without it some videos fail or show
fewer qualities. If either says NOT FOUND, run Setup again.

WHAT IT DOES NOT DO
Playlists, channels, audio only, captions. One video at a time. A
playlist address is refused with a message. Age-restricted and
members-only videos need a signed-in account, and this program does not
sign in.

USE IT FOR
Your own uploads, Creative Commons material, public-domain footage, and
anything you have permission to use. Downloading doesn't change who owns
the video.

WHERE THINGS ARE
C:\Program Files\YouTube Downloader          the program (read-only)
  app.py                 the program
  .venv\                 its own Python environment and download engine
  python\                the Python 3.11 that .venv runs on
  tools.json             where Setup found FFmpeg, Deno and uv
  install-log.txt        what Setup did, step by step
  setup-runtime.ps1      the runtime step Setup runs
%APPDATA%\YouTube Downloader\config.json
                         your folder, last quality and window size
%LOCALAPPDATA%\YouTube Downloader\engine\   engine updates
%LOCALAPPDATA%\YouTube Downloader\cache\    the engine's cache
Videos go to your Downloads folder until you choose another.

COMING FROM VERSION 1.0
The first time 1.1.0 opens, it copies your 1.0 settings from
%USERPROFILE%\YouTube Downloader\config.json. The 1.0 folder and its two
shortcuts are left alone. Once you are happy with 1.1.0 you can delete
that folder and the old shortcuts yourself.
The 1.0 zip (install.cmd, per-user install) is still on the download
page for anyone who cannot use the administrator prompt.

REMOVING IT
Settings > Apps > YouTube Downloader > Uninstall, or Uninstall in the
Start menu folder. Uninstall removes the program files Setup copied and
the icons. It leaves the Python environment (.venv and python folders,
tools.json, install-log.txt) in C:\Program Files\YouTube Downloader and
your settings in %APPDATA%, so nothing you made is deleted without you
deciding to. Delete those folders yourself if you want them gone.
FFmpeg, Deno and uv stay installed; other tools use FFmpeg.

Jeff A. Pierson . jeffapierson.com/journal_tools/
(c) 2026 Jeff A Pierson. Sharing and reposting permitted if the document
remains unaltered and attribution is retained. Commercial use requires
written permission.