Copyright (c) 2011 - 2013 by Johns.  All Rights Reserved.
Copyright (c) 2018 - 2021 by zillevdr.  All Rights Reserved.
Copyright (c) 2020 - 2023 by rellla.  All Rights Reserved.

License: AGPLv3

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.


Why do we need another softhddevice version?
--------------------------------------------
This is basically a fork of https://github.com/zillevdr/vdr-plugin-softhddevice-drm.git
and is aimed to merge all upstream commits back again - if possible.

The target of this version are embedded devices, see supported hardware.

The difference to the original fork is, that it adds some additional features like
resized video, hardware accelerated OSD rendering, support for Rpi4/5 and Amlogic
devices and a few more things. Read the commit history for detailed info.
There are a bunch of changes in the code, especially the drm handling was re-written and has
changed a bit to fully respect the atomic modesetting API now. Though everything should work
like it does with the original code, it's not guaranteed, that some bugs crept in.

As a principle, this softhddevice version is only dealing with mainline versions and standards,
which means you can (and have to) use mainline (or to be mainlined) kernel, ffmpeg and  mesa version.
This code does not work with vendor provided software or even closed source binaries.

www.LibreELEC.tv is good source to look for what is possible with mainlined media related software.
In the LibreELEC project you can find at least patches all the software, even if some piece of code
isn't able to be mainlined or simply not already there. Because LibreELEC is a distribution to run
kodi on, you'll find everything you need.


How does it internally work?
----------------------------
Video decoding is done with ffmpeg. If your hardware has some hardware decoder
and/or deinterlacer which is supported by ffmpeg, the video is hardware decoded
(depending on the codec), otherwise software decoding/ deinterlacing is done.
The OSD is either composed with OpenGL/ES or with CPU (see below).
Both, video and OSD are rendered directly on seperate drm planes with kms.
When the video is hardware decoded, we don't need much CPU, because everything is done
with a zero-copy approach. That's the same for OpenGL/ES OSD.


Supported Hardware:
-------------------
	Allwinner
	Amlogic
	Raspberry Pi 4+5
	Rockchip


Known Bugs/ TODO:
-----------------
	- PASSTHROUGH is broken
	- forward/backward seeking is buggy in general
	- amlogic: few artifacts and brightness issues,
	  when replay starts on hw decoded channels (720p, 1080i)
	- attach/detach isn't implemented
	- grabbing is not implemented yet


Install:
--------
	git clone https://github.com/rellla/vdr-plugin-softhddevice-drm-gles.git
	cd vdr-plugin-softhddevice-drm-gles
	make
	make install


OpenGL/ES:
----------
	OpenGL/ES support is based on the work of Stefan Braun
	(https://github.com/louisbraun/softhddevice-openglosd)

	This enables GPU accelerated OSD rendering.
	OpenGL/ES support is enabled, if gles2, egl and gbm are found on the system
	To disable OpenGL/ES support (if autodetected), simply build with

	GLES=0 make

	In this case, VDR is using CPU based OSD rendering.


Requirements:
-------------
        No running X!

	vdr (version >=2.2.x)
		Video Disk Recorder - turns a pc into a powerful set top box
		for DVB.
		http://www.tvdr.de/

	ffmpeg
		v4l2-request (Rockchip, Allwinner)	WIP LE version

	alsa-lib
		Advanced Linux Sound Architecture Library
		http://www.alsa-project.org

	For OpenGL/ES support:
		gles2 (Mesa)
		egl (Mesa
		gbm (Mesa)
		freetype2
		glm - OpenGL Mathematics (GLM)
		libpng (to write debug OSD pngs)

Commandline arguments:
----------------------
	Use vdr -h to see the command line arguments supported by the plugin.

		-a audio_device
		-p device for pass-through
		-c audio mixer channel name
		-d display resolution (e.g. 1920x1080@50)
		-w workarounds
			disable-ogl-osd (to disable HW accelerated OSD)

Setup:	environment
------
	ALSA_DEVICE=default
		alsa PCM device name
	ALSA_PASSTHROUGH_DEVICE=
		alsa pass-though (AC-3,E-AC-3,DTS,...) device name
	ALSA_MIXER=default
		alsa control device name
	ALSA_MIXER_CHANNEL=PCM
		alsa control channel name

Setup: /etc/vdr/setup.conf
------
	softhddevice-drm-gles.MakePrimary = 0
	0 = no change, 1 make softhddevice primary at start

	softhddevice-drm-gles.HideMainMenuEntry = 0
	0 = show softhddevice main menu entry, 1 = hide entry

	softhddevice-drm-gles.MaxSizeGPUImageCache = 128
	how many GPU memory should be used for image caching

	softhddevíce-drm-gles.WritePngs = 0
	0 = do nothing, 1 = write osd on every flush to /tmp
	this is only for debugging purposes

	softhddevice-drm-gles.AudioDelay = 0
	+n or -n ms
	delay audio or delay video

	softhddevice-drm-gles.AudioPassthrough = 0
	0 = none, 1 = PCM, 2 = MPA, 4 = AC-3, 8 = EAC-3, -X disable

	for PCM/AC-3/EAC-3 the pass-through device is used and the audio
	stream is passed undecoded to the output device.
	z.b. 12 = AC-3+EAC-3, 13 = PCM+AC-3+EAC-3
	note: MPA/DTS/TrueHD/... aren't supported yet
	negative values disable passthrough

	softhddevice-drm-gles.AudioDownmix = 0
	0 = none, 1 = downmix
	Use ffmpeg downmix of AC-3/EAC-3 audio to stereo.

	softhddevice-drm-gles.AudioSoftvol = 0
	0 = off, use hardware volume control
	1 = on, use software volume control

	softhddevice-drm-gles.AudioNormalize = 0
	0 = off, 1 = enable audio normalize

	softhddevice-drm-gles.AudioMaxNormalize = 0
	maximal volume factor/1000 of the normalize filter

	softhddevice-drm-gles.AudioCompression = 0
	0 = off, 1 = enable audio compression

	softhddevice-drm-gles.AudioMaxCompression = 0
	maximal volume factor/1000 of the compression filter

	softhddevice-drm-gles.AudioStereoDescent = 0
	reduce volume level (/1000) for stereo sources

	softhddevice-drm-gles.AudioBufferTime = 0
	0 = default (600 ms)
	1 - 1000 = size of the buffer in ms


SVDRP:
------
	PLAY Url    Play the media from the given url.
	Tested extension: *.mp3, *.mp4, *.m3u, *.m3u8

	Play a local file:
	svdrpsend plug softhddevice-drm-gles PLAY /path_to_file/media_file.mp4

	Play a playlist inside ConfigDirectory:
	svdrpsend plug softhddevice-drm-gles PLAY playlist_name.m3u

	Play a media file from web:
	svdrpsend plug softhddevice-drm-gles PLAY http://www.media-server/path_to_file/media_file.mp4