This archive contains libraries and scripts needed to restore DTS playback
as well as add Matroska DV support on LG Smart TVs, such as OLED CX models.

See RootMyTV/RootMyTV.github.io#72 for details.


License and disclaimers:
------------------------

GNU LGPL v2.1 or later (same as the GStreamer project and its plugins)

THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE
SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

THIS SOFTWARE IS *NOT* ENDORSED BY LG OR ANY OF ITS SUBSIDIARIES.


Limitations:
------------

- Root required (RootMyTV/RootMyTV.github.io#85)
- Only PCM stereo downmix supported (no multichannel, no passthrough).
- The libraries and scripts have been designed for LG OLED CX models.
  While there is a good chance that, if your TV is not too dissimilar to
  OLED CXs, you might also be able to restore DTS support there, any issue
  that arises from not running this software on an OLED CX is entirely
  yours to troubleshoot and support.


Installation:
-------------

- Open a root shell to your TV *using ssh* (not telnet!)
- Download, extract and run the installer by issuing something like:
  cd ~
  wget https://github.com/lgstreamer/dts_restore/archive/refs/tags/2.0.tar.gz
  tar -xzvf 2.0.tar.gz
  ./dts_restore-2.0/install.sh


Uninstallation:
---------------

- Open a root shell to your TV
- Run the commands:
  cd ~
  ./dts_restore-2.0/uninstall.sh
- Fully power off or reboot your TV.


Additional notes:
-----------------

- The DTS restoration process does not alter the original LG firmware
  content. All changes are applied in a temporary manner which means that,
  should you want reset media playback to its original behaviour, you can
  just remove the /var/lib/webosbrew/init.d/restore_dts init script or run
  uninstall.sh.
- If you still see the "This video does not support audio" message on first
  attempt, just close the video file and try again.
- If you want to adjust the stereo downmix settings, you can edit the
  [downmix] section from /var/lib/webosbrew/init.d/restore_dts (permanent)
  of /etc/gst/gstcool.conf (temporary).
- It is possible to disable DV support by simply creating a /tmp/dv_disable
  file on your system. If that file is found, then hybrid DV + HDR media
  will play as HDR. If using https://github.com/andrewfraley/magic_mapper
  you can map a DV enable/disable toggle by following the steps described
  at https://gist.github.com/pbatard/ea04494c0de63cd5d38b1f607ef64fbd.
- Depending on how they were mastered, hybrid DV + HDR media may use HDR
  rather than Dolby Vision. If that is the case, this is because the DV
  configuration used is *INCOMPATIBLE* with LG's implementation (meaning
  that trying to force DV over HDR would not work anyway).
- Depending on how they were mastered, hybrid DV + HDR media playing as
  DV may display a black screen when not started from the beginning (i.e.
  after performing a seek or resuming to a non 00:00:00 timestamp). If
  that is the case, use the disable DV switch above to play as HDR.


Source code:
------------

- libgstmatroska.so, libgstisomp4.so and libgstisomp4_1_8.so were compiled
  from the 1.14.4 LG 'gst-plugins-good' source for OLED CX models, with
  audio DTS demuxing re-enabled (and for Matroska Dolby Vision support added).
  The complete source for it, along with compilation instructions, can be
  found at: https://github.com/lgstreamer/gst-plugins-good
- libgstmpegtsdemux.so was compiled from the 1.14.4 LG 'gst-plugins-bad'
  source for OLED CX models, with audio DTS demuxing re-enabled.
  The complete source for it, along with compilation instructions, can be
  found at: https://github.com/lgstreamer/gst-plugins-bad
- libgstlibav.so was compiled from the 1.14.4 LG 'gst-libav' source for
  OLED CX models with the following changes applied for DTS (dca) decoding:
  * Force stereo downmix always.
  * Force integer output always.
  * Allow the reading of downmix coefficient from gstcool.conf.
  The complete source for it, along with compilation instructions, can be
  found at: https://github.com/lgstreamer/gst-libav