Video Downloader

Sample YouTube Data

Channel Name: Royalty Free Music - No Copyright Music
Channel URL: https://www.youtube.com/channel/UCQsBfyc5eOobgCzeY8bBzFg
Example Video: https://www.youtube.com/watch?v=6c2hT_f5Q2g

Table: url_dump

Column Name	Column Properties
id	- Integer - Primary Key - Auto-Incrementing
url	- YouTube video link (Example: https://www.youtube.com/watch?v=6c2hT_f5Q2g)
created_date	- Date and Time field - Must NOT be blank - Defaults to 'now'
download_date	- Date & Time when the video file was last downloaded

Table: youtube_links

Column Name	Column Properties
video_id	Auto incrementing positive number
url	Example: https://www.youtube.com/watch?v=6c2hT_f5Q2g
title	Running Backwards - Pentium Beats
publish_date	Mar 19, 2021
channel_name	Royalty Free Music - No Copyright Music
channel_url	https://www.youtube.com/watch?v=6c2hT_f5Q2g
download_date	Date & Time when the video file was last downloaded
processed_date	Date & Time when the file was last processed
filename_video
filename_audio
filename_description
filename_subtitles_en
filename_info_json
filename_thumbnail_webp
filename_thumbnail_jpg
video_codec	x264, x265, xvid, ...
video_resolution	1920x1080, 1080x720, ...
video_frame_rate	number of frames per second (25fps, 30fps etc)
audio_codec	mp3, aac, m4a, ...
audio_sample_rate	44KHz, 48Khz, ...

Reference Links

• SQLite - Syntax Documentation
• SQLite - Date And Time Functions
• youtube-dl - Youtube-DL GitHub Page

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Cron and Crontab

Windows Users (only)

If you are a Windows user, please refer to the following article which explains how you can add a cron job or scheduled task on Windows (not relevant for Mac / Linux users).

• How to add a cron job or scheduled task on Windows

Schedule jobs with crontab on macOS

Running scripts on your computer is great. Running them automatically is even greater. If you are on a Mac (or Linux), you can use our good friend crontab, which is a scheduling tool that will run jobs (scripts) at regular intervals.

Create / Edit crontab jobs

Use the following command to open crontab in edit mode:

crontab -e

You add a job to crontab by editing the job list. A job is specified in the following format (first line):

Useful Link

• Crontab Guru
• How to save output or errors to a file with Linux shell redirection
• BASH Shell Redirect Output and Errors To /dev/null
• How to redirect standard error in bash

Setting the script to run in crontab

On the Mac, we can use crontab -e to open an editor in Vim. Type i to enter Insert Mode which will allow you to edit the cron document. Once done, hit the Escape key to exit out of the Insert Mode. Next, type :wq to save and exit the crontab.

Here is an example python script that will execute every minute.

* * * * * say "Hi"; echo "Hello there. Can you see me on the terminal?"

Note: To comment out a crontab job, simply add a hash tag # in front of the line (crontab job).

List active crontab jobs

Use the following command to list all your active crontab jobs:

crontab -l

Delete all the cron job

Use the following command to delete all the cron jobs:

crontab -r

Log the output of a crontab jobs

Consider the following crontab job example.

* * * * * cd /Users/captaincodeau/My_Git_Code/My_Video_Downloader_AARV; echo "Yo" 1>> cron/logs/output.txt 2>> cron/logs/errors.txt

Here the 1>> redirects the standard output (if there is any) to cron/logs/output.txt and 2>> redirects the standard error (if there is any) to cron/logs/errors.txt.

Note that the >> represents 'append mode' and a single > represents 'write mode'.

Now try the following...

Copy the contents of cron/sample_cron.txt and paste them in your crontab using the command crontab -e. Remember to update the path with the appropriate path (as per your directory structure).

* * * * * cd /Users/captaincodeau/My_Git_Code/My_Video_Downloader_AARV; echo "Yo" 1>> cron/logs/output.txt 2>> cron/logs/errors.txt

After about a minute, you will find 2 new files in your /cron/logs directory. Checkout the contents of each file.