Using the .sh files used to work just fine but now it only works properly when "Render To File". When running the script any title causes the rendered output to be a white screen for the duration that the title text occurs.

I am certain it is probably an upgraded/conflicting package issue but have no clue what it would come down to.
Does anyone have any idea on how to solve or troubleshoot this?

Hello,
What distro / packages are you using? (AppImage? source build?)
Running the scripts from shell may miss all the environment setup from Kdenlive executable...

Thanks for the reply vpinon! How can I check the environment? Just to make it more clear the video is all playable and normal except any portions which have a text title are completely white. I would be so grateful to find the solution on why the .sh scripts don't work anymore. Even old .sh scripts that worked fine have the same problem now so I am confident the .sh script generation is no different and not the issue.

I am using 4:17.04.3+git201707101839~ubuntu16.04.1 from the Ubuntu PPA on Linux Mint 18.2 (Ubuntu 16.04)
Previously when I had 17.04.1 everything was fine but even reverting manually on another system has not fixed the problem.
I strongly suspect a new or upgraded package has broken things.

ii libmlt++3 6.5+git201704252005~ubuntu16.04.1 amd64 MLT multimedia framework C++ wrapper (runtime)
ii libmlt-data 6.5+git201704252005~ubuntu16.04.1 all multimedia framework (data)
ii libmlt6 6.5+git201704252005~ubuntu16.04.1 amd64 multimedia framework (runtime)
ii kdenlive 4:17.04.3+git201707101839~ubuntu16.04.1 amd64 non-linear video editor
ii kdenlive-data 4:17.04.3+git201707101839~ubuntu16.04.1 all non-linear video editor (data files)

I also ran melt manually and was getting these errors:

No LADSPA plugins were found!

Check your LADSPA_PATH environment variable.
[(null) 0x36b68a0] The MLT Qt module requires a X11 environment.
Please either run melt from an X session or use a fake X server like xvfb:
xvfb-run -a melt (...)
[producer_xml] failed to load transition "qtblend"
[(null) 0x36b68a0] The MLT Qt module requires a X11 environment.
Please either run melt from an X session or use a fake X server like xvfb:
xvfb-run -a melt (...)
[producer_xml] failed to load transition "qtblend"
[(null) 0x36b68a0] The MLT Qt module requires a X11 environment.
Please either run melt from an X session or use a fake X server like xvfb:
xvfb-run -a melt (...)
[producer_xml] failed to load transition "qtblend"
[mp3 @ 0x7f04f1ae9fa0] Estimating duration from bitrate, this may be inaccurate
[mp3 @ 0x7f05844e3e40] Estimating duration from bitrate, this may be inaccurate

This error shows the problem "The MLT Qt module requires a X11 environment".
Are you running a Wayland session or trying to render from a text console?

I am running the .sh files directly from SSH in a bash terminal, the same result also happens if running locally from the terminal.
Do you have any idea why they no longer render properly?

If running ssh from a X session, maybe you could try forwarding X (ssh -X or -Y).
Locally, you should run a graphical terminal (from an X session; as the same user).

Is there a way to make things work like before? I would always run the script from SSH with no X forwarding.
Would it help to show the rendered video so you can see the problem and I could send you the .sh, .mlt and .kdenlive file as I really do think there is a bug or some library has caused this weird issue.

Thanks vpinon!

Qt's need for X is very ancient, event back to Qt4 times...

I see a change in MLT last week: in /usr/share/mlt/core/loader.dict
the following line was added:
*.txt=qtext,pango
try removing this line if it is present?

Thanks I checked and removed it "*.txt=pango,qtext" but there is no difference in the rendering issue:

Contents of file below (after removing the suggested line). I also notice the xml tag is not closed at the end am guessing it is intentional?
=========

http://*=avformat,webvfx:plain:
https://*=webvfx:plain:
plain:http://*=webvfx:plain:
plain:https://*=webvfx:plain:
<?xml*=xml-string
*.mlt=xml
*.westley=xml
*.kdenlive=xml
*.melt=melt_file
*.inigo=melt_file
*.asf=avformat
*.avi=mcdv,avformat,libdv
*.bmp=pixbuf,qimage
*.dv=mcdv,avformat,libdv
*.dif=mcdv,avformat,libdv
*.exr=qimage
*.gif=pixbuf,qimage
*.graphics=xml
*.htm=webvfx:plain:
*.html=webvfx:plain:
*.jfx=xml
*.jef=xml
*.jpg=pixbuf,qimage
*.jpeg=pixbuf,qimage
*.kdenlivetitle=kdenlivetitle
*.kino=xml
*.kra=qimage
*.mp3=avformat
*.mov=mcdv,avformat,libdv
*.mpg=mcmpeg,avformat
*.mpeg=mcmpeg,avformat
*.mpl=pango
*.ogg=avformat,vorbis
*.pcx=pixbuf,qimage
*.pgm=pgm,pixbuf,qimage
*.png=pixbuf,qimage
*.psd=qimage
*.qml=webvfx:plain:
*.story=xml
*.svg=pixbuf,qimage
*.swf=avformat,swfdec
*.tga=pixbuf,qimage
*.tif=pixbuf,qimage
*.tiff=pixbuf,qimage
*.vob=mcmpeg,avformat
*.wav=avformat
*.wmv=avformat
*.xcf=qimage
*.xml=xml
*=avformat

Just FYI I reinstalled Linux Mint fresh and reinstalled the same version of kdenlive and it is still doing it. I suspect another related library has changed or been updated.

I fetched the .mlt file that is created when rendering from the GUI and compared to the the .mlt creating with the .sh script file and notice they do differ in format and also absolute path is used in the GUI .mlt to the movie clips. I'm now re-rendering manually specifying the GUI created .mlt with the .sh script and will report the result. If the GUI .mlt works properly then we know there is a bug in the .mlt created with the .sh script.

The result is still the same so it cannot be the .mlt files or .sh files. There is some difference in something between what gets rendered from the GUI vs the shell script. Titles with text just change the screen to complete white for the duration when rendering from the shell.

vpinon or anyone does anyone have an idea for a possible solution?
Thanks everyone!

For me it has been said several times that QGraphics module from Qt needs a graphics session (X11) to work.
So either you forward a display through ssh, or you run a VNC server on your host, or maybe a dummy framebuffer...

Running in a X session, script rendering works well;
without X melt works except Qt module (and maybe others like OpenGL etc)

But I don't understand why it worked normally from the SSH shell the whole time until suddenly? I would like to be able to do it headless without an X session. Could this be a mlt project problem or do you think it is kdenlive?