HDMI-CEC Remote control

[shoefone]

Apologies for replying to an old thread.

I was working with this today and got a bash script working to use the play/pause/fwd/back buttons on a TV remote. Running this as a service from boot works for me. After an album is started in moode, I can use my TV remote to play/pause/stop/skip back/skip fwd/rewind/ffwd.

I don't have anything yet for the UI, I am sure that will be more complicated. My thinking now is that something along the lines of using the up/down/left/right/select CEC codes to, say, tab through and select the links on the Chrome UI would probably do it. But some quick playing around with chrome didn't reveal anything that usable. Something to do!

I put in all of the CEC user codes defined in the spec, for future-proofing. My TV only supports a few of them, but I suspect others' TVs will support more and that this could likely be extended.

It's based on a script I found elsewhere (see the notes at the top of the script). I carried over the GPL license since I used a few of the lines of code direct from the other script. 

I'll put this on the git as well, though I'm not sure what the best practice is on that. 

Here is the (extremely verbose ) script:

Code:

# cec_mon_script_v2.0.sh
# Monitors CEC transmissions from TVs to control play/pause/ffwd/etc functions in moode audio. Does not control UI navigation (yet!)
# This has been tested by running it standalone, as well as as a service, according to https://www.wikihow.com/Execute-a-Script-at-Startup-on-the-Raspberry-Pi

# This script started from the example posted at
# https://ownyourbits.com/2017/02/02/control-your-raspberry-pi-with-your-tv-remote/
# The basic structure and a few lines of code from that are in this script
# Original copyright:
# Copyleft 2017 by Ignacio Nunez Hernanz <nacho _a_t_ ownyourbits _d_o_t_ com>
# GPL licensed (see end of file) * Use at your own risk!

# This is based in part on information from the CEC spec, found at
# https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/xtreamerdev/CEC_Specs.pdf

# The basic method is to read the log output from cec-client, line by line
# Traffic messages from the log output are parsed to see if they correspond to a known button event
# If they do, a call to music player daemon (mpc) is made, which corresponds to the desired user action
# To do this, a filter_key() function is defined which decides if there is a match between the known button event descriptor and the log message
# The log output us monitored in an infinite loop; any matches to filter_key() cause a mpc call to be made

# This regex is simple but tricky (to me at least!)
# It looks for lines beginning with 'TRAFFIC', which is a message->level string in cec-client (found in the CecLogMessage function)
# It then compares the last chars of the message against the chars of the message descriptor and control code sent to it (the $2 variable)
# The message descriptor and control code sent to it will match one of the items in the list of control codes manually defined below
# The TRAFFIC log items from cec-client define three things.
# UNKNOWN:MESSAGE_DESCRIPTOR:USER_CONTROL_CODE
# The first is unknown (always 02 on the tested system)
# The second defines, among other things, the button state (always 44 or 8B on the tested system), defined in table 13 of the spec
# The third defines the user action, defined in table 27 of the spec

filter_key(){ grep -q "TRAFFIC.*$1" <( echo "$2" ) ; }

# SCANJUMP defines how many seconds to jump when the rewind/ffwd buttons are pressed
# Format is HH:MM:SS
SCANJUMP="00:00:05"

# These are the Message Descriptor values based on the CEC spec
# Only one is included; it indicates that the button has been released
# Many others are defined in the spec (CEC Spec v1.3a, table 13)
Button_Up="8B"

# These are named User Control Code values based on the CEC spec
# Only a few of these are used in this version of the script (2.0)
# The others are either not available as control codes on the TV used for testing,
# or are available but have not been implemented (eg the up/down/left/right/select)
# TODO: implement moode audio UI navigation using these control codes

Select="00"
Up="01"
Down="02"
Left="03"
Right="04"
Right_Up="05"
Right_Down="06"
Left_Up="07"
Left_Down="08"
Root_Menu="09"
Setup_Menu="0A"
Contents_Menu="0B"
Favorite_Menu="0C"
Exit="0D"
Num_0="20"
Num_1="21"
Num_2="22"
Num_3="23"
Num_4="24"
Num_5="25"
Num_6="26"
Num_7="27"
Num_8="28"
Num_9="29"
Dot="2A"
Enter="2B"
Clear="2C"
Next_Favorite="2F"
Channel_Up="30"
Channel_Down="31"
Previous_Channel="32"
Sound_Select="33"
Input_Select="34"
Display_Information="35"
Help="36"
Page_Up="37"
Page_Down="38"
Power="40"
Volume_Up="41"
Volume_Down="42"
Mute="43"
Play="44"
Stop="45"
Pause="46"
Record="47"
Rewind="48"
Fast_forward="49"
Eject="4A"
Forward="4B"
Backward="4C"
Stop_Record="4D"
Pause_Record="4E"
Angle="50"
Sub_picture="51"
Video_on_Demand="52"
Electronic_Program_Guide="53"
Timer_Programming="54"
Initial_Configuration="55"
Play_Function="60"
Pause_Play_Function="61"
Record_Function="62"
Pause_Record_Function="63"
Stop_Function="64"
Mute_Function="65"
Restore_Volume_Function="66"
Tune_Function="67"
Select_Media_Function="68"
Select_AV_Input_Function="69"
Select_Audio_Input_Function="6A"
Power_Toggle_Function="6B"
Power_Off_Function="6C"
Power_On_Function="6D"
F1_Blue="71"
F2_Red="72"
F3_Green="73"
F4_Yellow="74"
F5="75"
Data="76"

while :; do
 # Try to capture Ctrl-C, in case the script is run directly
 trap break SIGINT
 cec-client | while read cec_line; do
   # Convert string to uppercase to avoid any system-specific differences
   # in how hex codes are represented (lowercase in tested system)
   cec_line=${cec_line^^}
   # Try to capture Ctrl-C, in case the script is run directly
   trap break SIGINT
   # The meat of the program: match output from cec-client against a known pattern, and issue a mpc command based on that
   if  filter_key "${Button_Up}\:${Pause}" "$cec_line"; then
     mpc pause
   fi
   if  filter_key "${Button_Up}\:${Play}" "$cec_line"; then
     mpc play
   fi
   if  filter_key "${Button_Up}\:${Stop}" "$cec_line"; then
     mpc stop
   fi
   if  filter_key "${Button_Up}\:${Backward}" "$cec_line"; then
     mpc prev
   fi
   if  filter_key "${Button_Up}\:${Rewind}" "$cec_line"; then
     mpc seekthrough -$SCANJUMP
   fi
   if  filter_key "${Button_Up}\:${Fast_forward}" "$cec_line"; then
     mpc seekthrough +$SCANJUMP
   fi
   if  filter_key "${Button_Up}\:${Forward}" "$cec_line"; then
     mpc next
   fi
 done
done

# License
#
# This script is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This script 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this script; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place, Suite 330,
# Boston, MA  02111-1307  USA