Audio Status #63

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1. trainman419 commented on Mar 7, 2023

   

   trainman419

   on Mar 7, 2023

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   No, I haven't had anyone asking for audio status, so I haven't looked into it. If you can explain briefly what you're trying to do, I might be able to help.
2. utdream commented on Oct 3, 2023

   

   utdream

   on Oct 3, 2023

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   Audio status is only loosely implemented in the HDMI-CEC specification itself. It rarely (never?) works on TV's and only works on things like sound bars. We need better implementation in the HDMI spec itself before it can really be implemented in an API like this IMHO.
3. r1ckdu commented on Jan 16, 2024

   

   r1ckdu

   on Jan 16, 2024

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   I know this is an old thread but I'd love to get an absolute volume reading. From what I have gathered the code that i need to evaluate is 15:71 (recorder to audio): "Give Audio Status"
   Returns 51:8e e.g. indicating that the volume is 14 and its muted -> hex sum of 80 + an integer of 0..127.

   This would be amazing to have because for my application I need an absolute volume scale.

   @trainman419 I have been able to do this using cec-client but I am not able to drive this from python...so this is where your python package came in ;)
4. nderr commented on May 15, 2024

   

   nderr

   on May 15, 2024

   Last edited by nderr

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   I poked around a little bit on this issue. You can add a wrapper for the libcec "GetAudioStatus" function without too much trouble, but as discussed here, libcec caches the first result and keeps returning it forever.

   The path of least resistance is probably to ask the audio system for the audio status directly, add a handler to grab the response, and cast the resulting parameter from bytes to int. For example, when I run the following...

   # audio_status_test.py
   
   import time
   import cec
   
   audio     = cec.CECDEVICE_AUDIOSYSTEM
   op_give   = cec.CEC_OPCODE_GIVE_AUDIO_STATUS
   op_report = cec.CEC_OPCODE_REPORT_AUDIO_STATUS
   
   recvd = False
   def cb(event, *args):
   
       print('event: ', event, ', data: ', args)
   
       par = args[0]
       init = par['initiator']
       comm = par['opcode']
   
       if init == audio and comm == op_report:
   
           byte_result = par['parameters']
           print(f'\n\nAudio Status: {int.from_bytes(byte_result,"big")}')
   
           global recvd
           recvd = True
   
   cec.add_callback(cb, cec.EVENT_COMMAND)
   cec.init()
   cec.transmit(audio,op_give)
   
   while not recvd:
       time.sleep(0.1)

   ...I get the following output.

   event:  4 , data:  ({'initiator': 0, 'destination': 15, 'ack': False, 'eom': False, 'opcode': 135, 'parameters': b'\x00\x009', 'opcode_set': True, 'transmit_timeout': 1000},)
   event:  4 , data:  ({'initiator': 0, 'destination': 1, 'ack': False, 'eom': False, 'opcode': 144, 'parameters': b'\x00', 'opcode_set': True, 'transmit_timeout': 1000},)
   event:  4 , data:  ({'initiator': 5, 'destination': 1, 'ack': False, 'eom': False, 'opcode': 122, 'parameters': b'$', 'opcode_set': True, 'transmit_timeout': 1000},)
   
   
   Audio Status: 36
   
5. utdream commented on May 17, 2024

   

   utdream

   on May 17, 2024

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   Yuk. That really sucks that libcec does that. I like your implementation of asking the device directly. Thank you!