Work-around if movie subtitles restart after the final subtitle is displayed

If I’m watching movies in a language I don’t understand, I want subtitles. On my computers this is possible as long as there is a subtitles file with the name suffix .srt and the same prefix name as the .mp4 video file in the same directory. I usually prefer to view movies on my TV with a bigger screen, so I copy the movie to a HDD that is normally connected to my TV (a FINLUX model 43-FUD-8020). However, the built-in media player in the TV does not show the subtitles in the .srt file, even when it is in the same directory as the .mp4 file. Therefore I use the MKVToolNix utility mkvmerge to put the movie and subtitles into a Matroska multimedia container (.mkv file), and the TV’s media player can play these .mkv files and does display the subtitles. In fact, so can my laptops and desktop running Linux (I have not tried on a machine running Windows 10, but I assume Windows 10 would have no trouble either).

To install in Lubuntu 20.10:

user $ sudo apt install mkvtoolnix

To install in Gentoo Linux:

root # emerge mkvtoolnix

To create a Matroska file containing the movie plus subtitles:

user $ mkvmerge -o movie_with_subtitles.mkv movie_without_subtitles.mp4 subtitles.srt

Normally the last subtitle in a movie does not occur at the very end of the movie. For example, there could be action without dialogue at the end of the movie, and/or final credits without dialogue. The media players on my laptops and desktop running Linux display the last subtitle and play the rest of the movie in the Matroska container as expected. However, the media player in my FINLUX TV displays the last subtitle and then displays the subtitles from the beginning again, at breakneck speed. Annoying to say the least. As the problem does not occur on my laptops and desktop with the same .mkv file, I assume the problem lies with the media player in the TV.

At first I suspected that the .srt file was the cause, but it correctly uses UTF-8 encoding and the syntax of the contents is correct. Anyway, just to be sure I ran it through an online cleaner for .srt files and re-generated the .mkv file, but that made no difference on the TV. Since there is no problem playing the .mkv file on my computers, I can only assume the TV’s media player is indeed at fault. I cannot do anything about the TV’s media player, so I came up with an acceptable work-around: I added a dummy subtitle at the end of the .srt file that is set to be displayed at the very end of the movie. For example, let’s say the movie duration is two hours, 12 minutes and twenty-two seconds but the last subtitle is at 01:56:38,201:

188
01:56:38,201 --> 01:56:40,286
The end justifies the means.

I edited the file and added a dummy subtitle at the end:

188
01:56:38,201 --> 01:56:40,286
The end justifies the means.

189
02:12:19,001 --> 02:12:21,999
THE END.

I then re-generated the .mkv file using the mkvmerge command and, lo and behold, after the subtitle displayed between at 01:56:38,201 and 01:56:40,286 the TV no longer displays any more subtitles until the very end of the movie when it displays ‘THE END’ and the video ends. Actually, in reality the movie must be very slightly longer than 02:12:21,999 because, after displaying ‘THE END’, the first six subtitles in the subtitle file are displayed in rapid succession before the media player stops playing, but that is no big deal.

I searched the Web quite a lot and was unable to find any mention of this particular problem, so I am posting my work-around here just in case it helps someone else experiencing the same problem.

‘IP configuration was unavailable’: a laptop cannot connect wirelessly to a router

I recently switched my ISP from BT to Virgin Media because the speed and reliability of the broadband connection were low. A Virgin Media Hub 3 was supplied as part of the package, and the TV, laptops (Gentoo Linux, Windows 10 and macOS), desktops (Lubuntu and Windows 10), tablets and phones (Android and iOS) could connect to the Hub 3 without any trouble. A few weeks later Virgin Media offered to upgrade the hub to a Hub 4. I don’t look a gift horse in the mouth, so I accepted the offer. The Hub 4 does indeed improve on the already excellent broadband speeds I was getting with the Hub 3. On the downside the Hub 4’s configuration software has a couple of bugs, but I was able to live with them.

In addition to the above-mentioned hub configuration bugs, one of my laptops (a Compal NBLB2 with Intel Wireless WiFi Link 5300 AGN adapter) running Linux could not connect to the hub via Wi-Fi, even though it had no trouble connecting to the Hub 3. All other devices so far can connect to the Hub 4, so I was scratching my head. The laptop has no trouble connecting to the Hub 4 via Ethernet cable.

The hub’s 5G and 2.4G Wi-Fi bands originally had the same SSID (I’ll call it ‘VM1234567‘ here). I decided to rename the two bands ‘VM1234567_5G‘ and ‘VM1234567_2.4G‘ respectively, via the hub’s Settings in a Web browser. Very occasionally the laptop could connect to either SSID, but usually it could not connect and the following notification would pop up:

Wireless interface (wlan0)
IP configuration was unavailable

I did various things to try to get the laptop to connect, such as:

  • changing Wi-Fi channel selection in the hub from Auto to Manual and specifying different channels myself;
  • specifying the BSSID in the Desktop Environment’s GUI front-end to NetworkManager;
  • explicitly restricting the connection to the specific (and only) Wi-Fi interface (‘wlan0‘, in my case) in the DE’s GUI front-end to NetworkManager;
  • disabling IPv6 (Virgin Media does not use IPv6) in the DE’s GUI front-end to NetworkManager;
  • disabling the UFW firewall.

None of the above enabled the laptop to connect to the hub via Wi-Fi.

I installed the GUI Wi-Fi scanner LinSSID on my other Linux machines so I could check which 2.4G and 5G Wi-Fi channels were being used by the hub and by my neighbours’ hubs/routers. Note that LinSSID requires the utility iw to be installed and CONFIG_CFG80211_WEXT to be set in the kernel. The NetworkManager command ‘nmcli dev wifi list‘ can also be used to check which channels are being used. The channels selected automatically by the hub looked reasonable to me, and the different channels I selected manually did not improve the situation.

Now, coincidentally that laptop can dual-boot Windows 7, so I booted Windows 7 to see if it could connect to the hub via Wi-Fi. However, Windows 7 had the same Wi-Fi connectivity problem as Linux. The Network and Sharing Centre displayed the error message ‘The default gateway is not available’ and allowed me to run the so-called Troubleshooter, which fixed the problem in Windows 7. The laptop could then connect to the hub and to the Internet via the 5G Wi-Fi band (the hub’s DHCP server allocated IP address 192.168.0.145 to the laptop). So it appeared the lack of a specified default gateway was the problem in both OSs. This surprised me because I had never had to specify a default gateway on my machines, and still do not have to on the other machines. Anyway, I booted back into Linux and did the following:

STEP 1 (on the Compal laptop)

Connected to the hub via an Ethernet cable.

Opened the Hub 4 Settings page (192.168.0.1) in a Web browser.

Selected ‘Advanced settings’ > ‘DHCP’

Added the MAC address of the laptop’s Wi-Fi adapter and the IP address 192.168.0.145 to the Reserved list.

STEP 2 (on the Compal laptop)

Selected ‘System Settings’ > ‘Network’ | ‘Connections’

Selected Wi-Fi connection VM1234567_5G

Entered the following on the ‘IPv4’ tab:

Method: Manual
DNS Servers: 194.168.4.100,194.168.8.100
Search Domains: cable.virginm.net (The laptop connects without this entry, so I’m not sure if it makes any difference.)

Clicked ‘+ Add’ and added the gateway details as follows:

Address
192.168.0.145

Netmask
255.255.255.0

Gateway
192.168.0.1

Ticked ‘IPv4 is required for this connection’.

Set the following on the ‘Wi-Fi’ tab (this is optional):

BSSID: <hub’s MAC address corresponding to the SSID>
Restrict to device: wlan0 (<MAC address of the laptop’s Wi-Fi adapter>)

The BSSID can be found either by using LinSSID on a machine that can access the Wi-Fi network or by using the command ‘nmcli dev wifi list‘ in a terminal window. The MAC address of the laptop’s Wi-Fi adapter can be found using the commands ‘ip link‘ or ‘ifconfig‘.

Clicked on the down arrow in the ‘Restrict to device:’ box and selected the device (wlan0, in my case).

STEP 3 (on the Compal laptop)

Selected ‘System Settings’ > ‘Network’ | ‘Connections’

Selected Wi-Fi connection VM1234567_2.4G

Performed the same configuration steps as for VM1234567_5G except that the SSID V1234567_2.4G has a different BSSID (found using LinSSID or nmcli) to the SSID V1234567_5G.

The laptop’s 5G W-Fi connection now works very well with the Hub 4. The 2.4G connection can be slow (even when the signal is at 100%) and sometimes stalls, so I’m not sure I have fixed that connection completely, or even if it is fixable in this case. I still do not know why the problem occurs with the Hub 4 but not the Hub 3, and why it only happens with one specific machine. Anyway, the 5G connection now works fine, so I’m happy.