Audio level setting

[darwindesign]

@Oxidant-veroplus

I know CEC is like a fax protocoll: Bidirectional connection protocoll between devices.
The data send over is digital , so basicly sampled audio channels coded in 1 or 0.
If you want to change a audio loudnes(volume) of sound you need to make the digital signal analog and resample the analoge signals. And send that over.

No, your conflating two completely separate things. CEC is like a really fancy two way remote control. All communication for CEC happens on one singular wire that is connected on all the devices and there is no other data that is sent or received on this line other than a bunch of control type communication. There is no audio being sent via CEC, there is no communication about protocols or anything else. It is just a bunch of this is who I am, can I take this identification, can everybody switch to me please, etc. It is just like a smart remote control pushing the buttons for you.

@Oxidant-veroplus

What i didn’t understand was why music, mp3 file, which is stereo 2.0 channel compressed PCMdata, doesn’t trigger the PCM volume change posibility as the compressed mp3 file is decoded back in two channels LPCM data by kodi and send over to the AVR. Right?

It does. Anything that isn’t set as a passthrough format get decoded to LPCM. Kodi’s internal volume control affects any of this audio.

@Oxidant-veroplus

So pasthrough all kind Dolby digital enabled doesnt send the mp3 file through right?

If you enable DD and transcode and have channels set to 2.0 (I’m pretty sure I’m repeating myself here) and you play a mp3 file then that file get decompressed at which point any of Kodi’s normal processing happens and then that modified audio then gets recompressed into an AC3 file that gets sent out.

It really seems like you have this idea that the whole process is more complicated than it really is. It is really not much different than the optical connection than your already familiar with. With toslink you have two uncompressed channels of audio that have the ability to transmit up to a certain data rate. You can encode compressed multichannel audio into these channels and send them along which is what regular AC3 and DTS is. With HDMI it is still basically the same thing, but with newer versions you have a lot more channels of audio and more bandwidth, but it is still the same thing. You still can only send the uncompressed audio or compressed formats that have been encoded onto that signal which still is (outside of niche) just DTS and Dolby formats.

[Oxidant-veroplus]

Sorry writing in a not native language is more difficult then face to face talking you easily roams off in a miscommunication. (i forgot the space between CEC sentence and the audio sentence which inclined it wasn’t two seperate subjects.)

I didn’t say CEC contained audiosignals i ment to say all audio which send through a hdmi cable is digital data. as far as i can read about it.
in better English: from wiki kodi page:

Following isn’t to learn you something (you know more then i ever can scrape from internet)
It’s explaining what i found about hdmi and cec and pcm and arc to learn myself more background: (you triggered me to dive in deep and i wanted to see every step explained as much as i grasp/understand can’t help myself if a question scratches the inside of my skull it stays there itching until i find a (close enough) answer even when it doesn’t matter in use of gear.)
google drift:
connector pin layout

Shows 3 channels and each channel has + 0 - 2.0 => 3x2 is 6 is 5 plus 1 => 5.1
https://www.alpha-audio.nl/achtergrond/bitstream-versus-lpcm (i hope you can see it in English or translate.)
shows how pcm/lpcm is made and transmitted. (a sampled analog signal in binairy code., each channel is a row of 1’s and 0 's depending on the bitdepth groups of 8 16 bits (is there higher?) to define a sample. AC-converting is already done by the maker of the source unles you have a analoge record player that has a analog signal as output.
the only time the audio is analoge is just before the amplifier section for the speaker output. (i think all other manipulation of the sound channels is now digital so sending it around is digital data.

With bitstreaming, the drive is essentially in direct contact with the receiver via the hdmi cable. The data passes without processing through the hdmi cable to the receiver which decodes and then converts it. This has the advantage of sending a signal over the hdmi cable that is immune to jitter: DTS, DTS HD (MA) and Dolby data consists of data packets rather than samples.
(pasthrough modes of kodi right?)

Back to your text:

@darwindesign

If you enable DD and transcode and have channels set to 2.0 (I’m pretty sure I’m repeating myself here) and you play a mp3 file then that file get decompressed at which point any of Kodi’s normal processing happens and then that modified audio then gets recompressed into an AC3 file that gets sent out.

that last : recompressed back in AC3 if it’s just stereo (mp3 for instance) i didn’t catch because i thought it only convert multichannel (5.1 7.1) like DTS hd/DD true hd in to 5.1 channel AC3 and not plain 2.0 stereo channels converted from mp3 towards PCM and be done with it.

spdiff/toslink: S/PDIF - Wikipedia
i understand the basics of Biphase mark code (channels of HDMI uses the same kind i think but splitted to get 2 channels + 0 -)
What i can’t find is how this is done with light(optical cable which i assume is one glasfiber). (there isn’t “negative light” only light and no light ) i assume they use intensity levels full bright and half-bright.

anyway: all this above shows bitstreaming is preferred (pasthrough-modes in kodi)
And in order to use multiple remotes for the same: volume control CEC needs to be active.
ARC does give some advantages but also headaches and confusion:

HDMI ARC and eARC: Audio Return Channel for beginners

Why PCM volume control of kodi is completely gone/not visible in the user interface if there is any kind of pasthrough is still unclear to me. (what triggered me to test every possible connection in order to see if i could get it back on screen.) A current status but grayed out (not active) would help. (like the web interface has) and in kodi/system/ audio/ settings stil available for adjustment even when it’s not active would make it even more easy check settings.
i understand it is connected to the transcoding program: e-AC3 to pcm =>kodi’s volume control => pcm to AC3 (bitstreaming out to AVR)
Bitstream itself has no user control in volume that is only later after the AVR digital/analog converter (reciever chip?) or maybe after the reciever chip there is a separate DAC/channel which is connected to the control and power amplifier. That big knob on the reciever (that part i don’t care yamaha sound expertise does that for me i just select and turn the big knob. )

resume:
TV audio: ARC hdmi port did cause strange effects wile plain optical spdiff/toslink worked like a charme. (only lipsync needs a tiny small adjustment) So netflix/ plain tv is or just tv speakers or if the reciever is active jumped to AV4 (toslink tv connection) and the tv speakers are muted and CEC can control the reciever’s volume.(even Yatse (android) can control my receiver.)

Nass related files managed by kodi library are mostly passthrough by hdmi 1.4 and CEC controls basics. rest can be done with the reciever-remote.
everything works like a charme.

On question i like to find a answer for is : mp3 (320bps) is lossy but for most ears good enough to listen music without a feel of wrong sound. So i didn’t stored flac-files. and always just listend by toslink connection music out my reciever (old yamaha rxv440rds)
https://www.yamaha.com/dealers/bestbuy/RX-V473/pop_tabs1.htm
shows mp3 enhancing but in order to use that kodi must sent mp3 unprocessed through the HDMI cable right?
i hope i understand you correct and mp3 gets converted to ac3, so do i lose that feature or not?
Does the mp3 properties remain in the ac3 in such a way that the reciever recognize “mp3”?

Not that it matters a lot if i don’t hear the difference but hence i dived in so deep i can grasp this oyster shell for the pearl too.

[darwindesign]

I hope you don’t mind too much if I kind of skip over some of your questions here as although they are somewhat relevant generally speaking, they are more general audio processing and transmitting stuff that isn’t really specific to Kodi or OSMC. There are other places on the internet where these types of questions and discussions are better suited. Well, except for this, because I can’t help myself…

@Oxidant-veroplus

What i can’t find is how this is done with light(optical cable which i assume is one glasfiber). (there isn’t “negative light” only light and no light ) i assume they use intensity levels full bright and half-bright.

That is just a strand of unextraordinary clear plastic inside of a dark sleeve that is butted up to a LED that is no different than what you would find as an indicator light on the front of a million different electronic devices and which is read on the other end by a light sensor which is close to the same thing your TV uses to pick up the signal from your remote control. It reads if there is light there or not on a timed interval to get a proper string of 0’s and 1’s. You really don’t need to know this to use a toslink connection. It was also much more impressive in the '80’s.

@Oxidant-veroplus

Why PCM volume control of kodi is completely gone/not visible in the user interface if there is any kind of pasthrough is still unclear to me.

Controlling volume like this is a dirty hack. Your lowering the volume by limiting your dynamic range which increases your noise floor. This is not something that is generally done by most devices that transmit audio. Kodi included this ability to broaden the configuration choices in certain types of setups, but it is not an ideal choice for audio quality. If you have a remote that can control volume on the downstream device then this is what you want. Kodi changing between volume being controlled internally via said dirty hack, or via CEC has nothing to do with if passthrough is enabled. If there is a CEC amplifier device it can see then it uses it, as it should, because that is the better option. If your using a remote control that doesn’t send volume commands to Kodi itself, then it becomes irrelevant. If your using a universal remote then you should be sending volume commands directly to your TV/AVR/soundbar/etc depending on specifics of setup.

The why it is there in some of the apps and web interfaces is easiest explained by legacy limitations and nobody volunteering or caring to update when newer control protocols were put in place.

@Oxidant-veroplus

only lipsync needs a tiny small adjustment

Your AVR may have a relevant setting that can be turned on or off to fix that. It may have an auto setting that is auto making it wrong. Kodi can adjust it as well, even if you are using passthrough.

@Oxidant-veroplus

shows mp3 enhancing but in order to use that kodi must sent mp3 unprocessed through the HDMI cable right?

That would be if you were directly playing a mp3 file on your AVR. Lots of devices have this type of thing. Stick a file on a thumb drive and plug that into your AVR if you want to to hear what it does. This is not relevant to Kodi as, as previously stated, you can only send PCM over HDMI, you can’t send a MP3 file.

@Oxidant-veroplus

Does the mp3 properties remain in the ac3 in such a way that the reciever recognize “mp3”?

MP3=throw away some of the less noticeable parts of the audio, and squeeze down the rest.
MP3->PCM=Just an uncompressed version of exactly what was left behind when the MP3 file was made. Playing this file should be the same as playing the MP3.
MP3->PCM->AC3=Throw away some of the less noticeable parts of the audio that already had some less noticeable parts of the audio removed and then squeeze the down the rest.

This sounds bad, it probably is if you can hear it, probably doesn’t matter if you cant. Neil Young likely wouldn’t approve. Neil Young is also unlikely to come to your house for a listening party.

[Oxidant-veroplus]

@darwindesign

You really don’t need to know this to use a toslink connection. It was also much more impressive in the '80’s.

One string of 0 and 1’s is one channel, mono. I was wondering how they sqeezed in 2.0 (stereo.) but yes it red laser led light.

Lipsync can be adjusted on my tv, veroplus, AVR. I start by the AVR because that’s the last in the row.

Mp3 on a thumbnail is one of the things i think i try out to test how much difference i hear. Just for fun. I think Neil Young doesn’t know i am alive…
I am not afriad i miss out in the loss of musicdata. Hearing is less due age and clubhouse music in the 90ties.

[darwindesign]

@Oxidant-veroplus

One string of 0 and 1’s is one channel, mono. I was wondering how they sqeezed in 2.0 (stereo.)

Records used to be mono, then they were ubiquitously stereo, and then came quadraphonic. There was only ever one groove. The laser on a CD is only reading a single track and stereo sound came out. The reason toslink exists was to transmit that single stream of data from a CD to an external device. A single stream of data does not mean you are limited to mono.

@Oxidant-veroplus

but yes it red laser led light.

It is not a laser, just a very ordinary LED. People have a tendency to think fancy, high tech, complicated. My point was that sometimes it is just a light blinking through a piece of plastic.

@Oxidant-veroplus

Hearing is less due age and clubhouse music

I guess it should have been a bit less Apex Twins and a bit more Mark Farina