Download JWPlayer .ts files, merge them into a single file and then convert the file to .mp4

jwplayer_downloader.py

"""
For my Neuroengineering course presentation my group wanted to download some videos,
the problem is that those videos were played by the JWPlayer, so obtaining the video
files was a little tricky. What I noticed from observing the network traffic is that
JWPlayer downloads the video files in chunks (each chunk was 4 seconds long) and
in .ts format. My goal was to combine all of those small video segments into a single
one and then convert the file to .mp4. To combine the multiple video chunks into one
I used the "cat" command and to convert resulting .ts file to .mp4 I used the "ffmpeg"
tool.

This tool is purpose-specific, so you'll need to adapt it for your own case. We were
in a hurry and this a script that I quickly put up so that we could proceed with work.
I'm leaving this here in case someone else encounters a similar task, you can use
this file as a guide.

Tested only on Linux, but should work just fine on OSX. Might need adaptations for Windows.

Requirements:
  * Python 3.x
  * "ffmpeg" command-line tool.
"""
import sys
import urllib.request
from os import system, remove

# used to generate the correct file names, so that they
#  can be downloaded. This was purpuse-specific, so you might
#  wanna change that.
index_begin = int(sys.argv[1])
index_end = int(sys.argv[2])
out_file_name = sys.argv[3]

url = 'http://videos-f.jwpsrv.com/content/conversions/24tOJIfp/videos/vWqXqYoa-29646386.mp4-{}.ts'
file_name = 'vWqXqYoa-29646386.mp4-{}.ts'
file_names = []
for i in range(index_begin, index_end + 1):
    curr_file_name = file_name.format(i)
    curr_url = url.format(i)
    file_names += [curr_file_name]
    print('Downloading {}'.format(curr_url))
    urllib.request.urlretrieve(curr_url, curr_file_name)

print('All files downloaded')
print('Joining into a single .ts file...')


command = ''

for file_name in file_names:
    command += '{} '.format(file_name)

command = 'cat ' + command + '> {}'.format(out_file_name + '.ts')

system(command)

system('ffmpeg -i {}.ts -acodec copy -vcodec copy {}.mp4'.format(out_file_name, out_file_name))
print('Clenaing up...')

for file_name in file_names:
    remove(file_name)

remove('{}.ts'.format(out_file_name))

print('Done!')

In a similar vein, I had a video that was sparsely populated, so it would go 1, 5, 6, 10, 11, 12, 13, 15 etc. And sometimes the files were there but unplayable (They were less than 1kb), So I made this modification:

i = 0
failcount = 0
failmax = 10
fileminsizeb = 2048

while True:
    curr_file_name = file_name.format(i)
    curr_url = url.format(i)
    file_names += [curr_file_name]
    print('Downloading {}:'.format(curr_file_name), end="")

    try:
        urllib.request.urlretrieve(curr_url, curr_file_name)
    except:
        print(" error downloading.", end="")
        file_names.pop()
        i = i+1
        failcount = failcount + 1
        print("")
        if (failcount > failmax):
            break
        continue

    try:
        if( os.path.getsize(curr_file_name) < fileminsizeb ):
            print(f" File too small { os.path.getsize(curr_file_name) }", end = "")
            os.remove(curr_file_name)
            i = i+1
            failcount = failcount + 1
            print("")
            if (failcount > failmax):
                break
            continue
    except:
        print(f" Error resolving local path {curr_file_name}", end="")

    i = i+1
    failcount = 0
    print(" Success")