@echo off
REM Batch Script for downloading videos with yt-dlp from YouTube and other websites, accepting URL as input via command line.

REM Clear any previous download commands to avoid conflicts
setlocal ENABLEEXTENSIONS
set LC_ALL=C & SET _='' & setLOCAL ENGLISH

REM Accept a video URL as command-line argument (no prompt) and verify its presence
IF "%~1"=="" (
    ECHO No input provided. Usage: scriptname "https://www.youtube.com/watch?v=VIDEO_ID" & GOTO EndScript
) ELSE (SET InputUrl=%~1 & ECHO %InputUrl%)

REM Define yt-dlp path and format for downloading videos up to 1080p in MKV container with the best audio quality
set "YT_DL_CMD=yt-dl.exe --format "bestvideo[height<=1080]&bestaudio[ext=mp3,quality=5][codec:bestaudio]"

REM Run yt-dlp to download videos and extract the output filename for ffmpeg use
FOR /F delims== %%A IN ('%YT_DL_CMD%') DO SET "YT_DL_COMMAND=%%A"

SET "OUTPUTFILE=downloaded_video.mkv"

REM Execute yt-dlp command and pipe the output to ffmpeg for conversion if necessary
call :DownloadAndConvert "%InputUrl%" "%OutputFile%"
GOTO EndScript

:DownloadAndConvert
set "VideoUrl=%~1"
set "OutputFile=%~2"
REM Inform about processing download...
echo Processing download of %VideoUrl%...
%YT_DL_COMMAND% -o "%OutputFile%" "%VideoUrl%" && (
    REM Use ffmpeg to convert audio track if not already in AAC format and output MKV file
    ffmpeg -i "%OutputFile%.mp3" -c:v copy -c:a aac "%OutputFile%.aac" && (
        Echo Conversion to AAC complete. MKV video is ready with audio track in the same folder as MP3 file.
        REM The final .mkv file will be located at "%OutputFile%".mkv
    ) || (
        ECHO Failed to convert video, make sure ffmpeg is installed and available in PATH or provide full path for FFMPEG command here.
    )
GOTO EndScript

:EndScript
REM Documentation of the script can be found below this line
REM Usage instructions are provided above as a comment when running the batch file from the command prompt.
REM Ensure yt-dlp and ffmpeg executables are accessible or provide full paths in variables YT_DL_CMD and FFMPEG_COMMAND respectively before execution.