reddit_video_downloader.py

import json
import os
from requests import get, exceptions
from sys import argv as command_line_args

def get_user_agent():
    # some fake one I found :/
    return 'Mozilla/5.0 (iPad; U; CPU OS 3_2_1 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Mobile/7B405'

def say(text, type=''):
    if type == 'error':
        prefix = '\n[!] '
    else:
        prefix = '[>] '

    print(prefix + text)

def get_video(url):
    try: # checks if link is valid
        r = get(
            url + '.json',
            headers = {'User-agent': get_user_agent()}
        )
    except exceptions.MissingSchema:
        say('Please provide a valid URL', 'error')
        quit()

    if 'error' in r.text:
        if r.status_code == 404:
            say('Post not found', 'error')
            quit()

    try:
        json_data = json.loads(r.text)[0]['data']['children'][0]['data']
        say('Post Found!')
        say(f'Title: {json_data["title"]}')
        say(f'In sub-reddit: {json_data["subreddit_name_prefixed"]}')
        say(f'Posted by: {json_data["author"]}')
    except json.decoder.JSONDecodeError:
        say('Post not found', 'error')
        quit()

    try: # checks if post contains video
        video_url = json_data['secure_media']['reddit_video']['fallback_url']
        say(f'Video URL: {video_url}')
        r = get(video_url).content
        with open('download.mp4', 'wb') as file:
            file.write(r)
        get_audio(json_data)
        stitch_video()
    except TypeError:
        say('Only posts with videos are supported', 'error')

def get_audio(json_data):
    try:
        audio_url = json_data['secure_media']['reddit_video']['hls_url'].split('HLS')[0]
        audio_url += 'HLS_AUDIO_160_K.aac'
        r = get(audio_url).content
        with open('audio.aac', 'wb') as file:
            file.write(r)
    except TypeError:
        say('No audio found.', 'error')

def stitch_video():
    os.system("ffmpeg -i download.mp4 -i audio.aac -map 0 -map 1:a -c:v copy -shortest output.mp4")

def help_page():
    print(f"""
        Usage : {os.path.basename(command_line_args[0])} <URL_TO_POST_WITH_VIDEO>
    """)

num_of_args = len(command_line_args)
if num_of_args in [0, 1]:
    help_page()
else:
    get_video(command_line_args[1])