Extracting/splitting HDMI audio

MassiveJim · 24 Sep 2020 at 11:14

I have an LG C9 and a Marantz NR1504, because of this all of my sources are routed through the TV and use ARC to transmit sound to the receiver.
However there is a small issue that every now and then the sound will drop out for about a second and its highly annoying.

I was on the hunt for a newer receiver that supports eARC but have just discovered that LG haven't properly implemented eARC and there are issues with it.

So is it possible/easy to split the audio from a HDMI source and send it directly to the receiver ?

When I have searched online it seems to be a "box of tricks" that handles this, I don't know enough about the standards and cables to know exactly how it works but in my head you could have some kind of splitter cable that just took the audio channels so that you could send them seperately to a receiver.

Also apart from the HDMI output on my TV how can I get audio from the TV to the receiver (For netflix/Prime/TV/etc)

Please educate me

ik9000 · 24 Sep 2020 at 11:29

I've seen products that claim to do it, but not tried them myself. HDMI switch with audio outputs is what you're after. Whether it will be HDPC compliant I don't know. I think some of them are

Radox-0 · 24 Sep 2020 at 12:40

MassiveJim said:
I have an LG C9 and a Marantz NR1504, because of this all of my sources are routed through the TV and use ARC to transmit sound to the receiver.
However there is a small issue that every now and then the sound will drop out for about a second and its highly annoying.

I was on the hunt for a newer receiver that supports eARC but have just discovered that LG haven't properly implemented eARC and there are issues with it.

So is it possible/easy to split the audio from a HDMI source and send it directly to the receiver ?

When I have searched online it seems to be a "box of tricks" that handles this, I don't know enough about the standards and cables to know exactly how it works but in my head you could have some kind of splitter cable that just took the audio channels so that you could send them seperately to a receiver.

Also apart from the HDMI output on my TV how can I get audio from the TV to the receiver (For netflix/Prime/TV/etc)

Please educate me

What issues are there with eARC? I have a C9 and eARC receiver and with the latest update it works pretty great for me. Everything connects to TV then eARC to AVR which is hidden away as it turns on and off with the TV. With mentioned C9 latest update, TV pass's through LPCM signals fine so things like the PC can individually see and address each speaker connected to the AVR, amazing for gaming.

With that said, I know people look at HDFury devices when they do not go down the eARC route to split the Audio and video. Only thing is if its HDMI 2.0 passthrough (AFAIK) which is fine, but not sure what devices you want to use and if you may be wanting HDMI 2.1 (PS5, Xbox, 3xxx GPU etc) and its associated feature set.

Jez · 24 Sep 2020 at 12:43

Search amazon/ebay for "HDMI audio extractor"

I use one for my home cinema, as my receiver is high end, but very old and doesnt support HDMI video, etc. So i just bypass it for video with an HDMI switch box and extract audio from the output of that

lucid · 24 Sep 2020 at 13:35

MassiveJim said:
(1) So is it possible/easy to split the audio from a HDMI source and send it directly to the receiver ?

(2) When I have searched online it seems to be a "box of tricks" that handles this, I don't know enough about the standards and cables to know exactly how it works but in my head you could have some kind of splitter cable that just took the audio channels so that you could send them seperately to a receiver.

(3) Also apart from the HDMI output on my TV how can I get audio from the TV to the receiver (For netflix/Prime/TV/etc)

Please educate me

You've already answered your own first (1) question because you've found boxes that split the audio.

The answer to your second (2) question has a few parts. The most important bit is to understand what the TV does with the audio it gets. i.e. "does the sound format stay the same or does the TV change it?" The answer as far as ARC and Optical goes is it changes it. Any HD audio formats get dropped to the standard lossy versions, so Dolby True HD gets reduced to standard lossy Dolby Digital.

HDMI ARC is limited in what it can do with sound. There are also some additional limits often encountered because of the way TV manufacturers decide to handle DTS audio: Luckily, your C9 is one of the few TVs that will pass through DTS 5.1 unchanged.

eARC can pass HD audio, but as you'be found, LG hasn't set this up right on your TV.

Next, marry that bit of info up with the sound capabilities of your receiver. It can do everything up to HD audio. Being a 5.1 receiver though it doesn't have much use for anything that involves Dolly ATMOS. That's not a problem though because anything that is encoded for ATMOS will play in the highest grade 5.1 version by default.

Now look at your audio signal sources. You'll have apps on the TV (Netflix, Prime, catch-up TV maybe?). The TV sound itself from Freeview/Freesat if you're using those. Then there are any external sources you might have such as a console or video disc player.

Netflix and Prime output Dolby Digital 5.1 (DD5.1) as it core high quality format. ATMOS is supported by DD+
Freeview and Freesat output DD5.1 at best
Sky Q the V6 Virgin Tivo boxes output DD5.1 as best core format, and DD+ for ATMOS
Consoles can output multichannel uncompressed pcm in up to 7.1 format, or be set to convert that to DD5.1 or DTS5.1 . I know there was talk of games having DTS:X which is the ATMOS version of DTS-HD Master Audio, an uncompressed HD audio format.
BD players and UHD 4K disc players will output Dolby Digital TrueHD and DTS-HD Master Audio and the ATMOS and DTS:X versions

All of the above in contingent on the programme you're watching or the game you're playing or disc you're watching having the audio encoding.

So, pulling all this together means that to get the best sound from your external sources such as a disc player or Firestick or console, you should put the signal through the receiver and let it deal with sound.

Routing everything via the TV and using either HDMI ARC or Optical Audio will still give you DD5.1 and DTS5.1 as the best audio from the TVs own streaming apps and internal tuners which is really all you need. However, ARC and Optical won't handle HD audio, so that means you're losing sound quality from any source that carries Dolby True HD or DTS-HD MA.

There's no problem having the TV use either ARC or Optical. They both deliver the same quality of sound. HDMI ARC has the advantage of being able to communicate with the amp so that the TV can control the amp volume.

Trying an audio stripper on the eARC output of the TV might work so long as the TV sees it as a valid eARC sink device. TBH though, it seems like a lot of hassle to go through just to get HD audio from a source that could easily be connected to the amp first then the TV without all the cost and hassle of an audio stripper.

MassiveJim · 24 Sep 2020 at 20:27

lucid said:
You've already answered your own first (1) question because you've found boxes that split the audio.

The answer to your second (2) question has a few parts. The most important bit is to understand what the TV does with the audio it gets. i.e. "does the sound format stay the same or does the TV change it?" The answer as far as ARC and Optical goes is it changes it. Any HD audio formats get dropped to the standard lossy versions, so Dolby True HD gets reduced to standard lossy Dolby Digital.

HDMI ARC is limited in what it can do with sound. There are also some additional limits often encountered because of the way TV manufacturers decide to handle DTS audio: Luckily, your C9 is one of the few TVs that will pass through DTS 5.1 unchanged.

eARC can pass HD audio, but as you'be found, LG hasn't set this up right on your TV.

Next, marry that bit of info up with the sound capabilities of your receiver. It can do everything up to HD audio. Being a 5.1 receiver though it doesn't have much use for anything that involves Dolly ATMOS. That's not a problem though because anything that is encoded for ATMOS will play in the highest grade 5.1 version by default.

Now look at your audio signal sources. You'll have apps on the TV (Netflix, Prime, catch-up TV maybe?). The TV sound itself from Freeview/Freesat if you're using those. Then there are any external sources you might have such as a console or video disc player.

Netflix and Prime output Dolby Digital 5.1 (DD5.1) as it core high quality format. ATMOS is supported by DD+
Freeview and Freesat output DD5.1 at best
Sky Q the V6 Virgin Tivo boxes output DD5.1 as best core format, and DD+ for ATMOS
Consoles can output multichannel uncompressed pcm in up to 7.1 format, or be set to convert that to DD5.1 or DTS5.1 . I know there was talk of games having DTS:X which is the ATMOS version of DTS-HD Master Audio, an uncompressed HD audio format.
BD players and UHD 4K disc players will output Dolby Digital TrueHD and DTS-HD Master Audio and the ATMOS and DTS:X versions

All of the above in contingent on the programme you're watching or the game you're playing or disc you're watching having the audio encoding.

So, pulling all this together means that to get the best sound from your external sources such as a disc player or Firestick or console, you should put the signal through the receiver and let it deal with sound.

Routing everything via the TV and using either HDMI ARC or Optical Audio will still give you DD5.1 and DTS5.1 as the best audio from the TVs own streaming apps and internal tuners which is really all you need. However, ARC and Optical won't handle HD audio, so that means you're losing sound quality from any source that carries Dolby True HD or DTS-HD MA.

There's no problem having the TV use either ARC or Optical. They both deliver the same quality of sound. HDMI ARC has the advantage of being able to communicate with the amp so that the TV can control the amp volume.

Trying an audio stripper on the eARC output of the TV might work so long as the TV sees it as a valid eARC sink device. TBH though, it seems like a lot of hassle to go through just to get HD audio from a source that could easily be connected to the amp first then the TV without all the cost and hassle of an audio stripper.

Is there a simple cable that will extract the hdmi audio (hdmi splitter) I can run one cable from source to TV and one to the receiver

I use Netflix on the TV a lot which means I'm getting compressed audio (along with these annoying sound drop outs) I assume the only way to get better audio is to watch Prime/netflix etc on a seperate source such as a firestick.

Sources are xbox (series x is on preorder) and a HTPC
currently have a ps4 on loan from a mate as well

Radox-0 · 25 Sep 2020 at 02:30

lucid said:
You've already answered your own first (1) question because you've found boxes that split the audio.

The answer to your second (2) question has a few parts. The most important bit is to understand what the TV does with the audio it gets. i.e. "does the sound format stay the same or does the TV change it?" The answer as far as ARC and Optical goes is it changes it. Any HD audio formats get dropped to the standard lossy versions, so Dolby True HD gets reduced to standard lossy Dolby Digital.

HDMI ARC is limited in what it can do with sound. There are also some additional limits often encountered because of the way TV manufacturers decide to handle DTS audio: Luckily, your C9 is one of the few TVs that will pass through DTS 5.1 unchanged.

eARC can pass HD audio, but as you'be found, LG hasn't set this up right on your TV.

Next, marry that bit of info up with the sound capabilities of your receiver. It can do everything up to HD audio. Being a 5.1 receiver though it doesn't have much use for anything that involves Dolly ATMOS. That's not a problem though because anything that is encoded for ATMOS will play in the highest grade 5.1 version by default.

Now look at your audio signal sources. You'll have apps on the TV (Netflix, Prime, catch-up TV maybe?). The TV sound itself from Freeview/Freesat if you're using those. Then there are any external sources you might have such as a console or video disc player.

Netflix and Prime output Dolby Digital 5.1 (DD5.1) as it core high quality format. ATMOS is supported by DD+
Freeview and Freesat output DD5.1 at best
Sky Q the V6 Virgin Tivo boxes output DD5.1 as best core format, and DD+ for ATMOS
Consoles can output multichannel uncompressed pcm in up to 7.1 format, or be set to convert that to DD5.1 or DTS5.1 . I know there was talk of games having DTS:X which is the ATMOS version of DTS-HD Master Audio, an uncompressed HD audio format.
BD players and UHD 4K disc players will output Dolby Digital TrueHD and DTS-HD Master Audio and the ATMOS and DTS:X versions

All of the above in contingent on the programme you're watching or the game you're playing or disc you're watching having the audio encoding.

So, pulling all this together means that to get the best sound from your external sources such as a disc player or Firestick or console, you should put the signal through the receiver and let it deal with sound.

Routing everything via the TV and using either HDMI ARC or Optical Audio will still give you DD5.1 and DTS5.1 as the best audio from the TVs own streaming apps and internal tuners which is really all you need. However, ARC and Optical won't handle HD audio, so that means you're losing sound quality from any source that carries Dolby True HD or DTS-HD MA.

There's no problem having the TV use either ARC or Optical. They both deliver the same quality of sound. HDMI ARC has the advantage of being able to communicate with the amp so that the TV can control the amp volume.

Trying an audio stripper on the eARC output of the TV might work so long as the TV sees it as a valid eARC sink device. TBH though, it seems like a lot of hassle to go through just to get HD audio from a source that could easily be connected to the amp first then the TV without all the cost and hassle of an audio stripper.

Genuine question, what has LG not set up right properly? seen this mentioned a few times and not had any issues myself with eARC and LG OLEDs, but hardly use a wide range of formats so likely easily missed I expect more then anything. (not that I should actively look for issues heh)

Cheers

lucid · 25 Sep 2020 at 03:03

Radox-0 said:
Genuine question, what has LG not set up right properly? seen this mentioned a few times and not had any issues myself with eARC and LG OLEDs, but hardly use a wide range of formats so likely easily missed I expect more then anything. (not that I should actively look for issues heh)

Cheers

There are (at least) a couple of problems. LG seems to have had a long-running issue with how it has implemented the handshake between devices using ARC. It doesn't affect everything, but users are reporting issues with certain equipment combinations and Dolby Digital 5.1 when HDMI CEC is enabled which is what's required to get ARC working.

There are also some problems with eARC too. These are different. eARC uses the redundant connections that should have been used for HDMI Ethernet support rather than sharing the data channels of other connections. This means that CEC doesn't need to be switched on for eARC to work. However, with DD5.1 again, there are reports of significant lip sync issues (this is also reported for ARC).

Other issues include LG's version of eARC not supporting PCM 5.1 and PCM 7.1 audio, so games consoles that use PCM send uncompressed HD audio run in to a brick wall. This seems to be an error of omission, but I haven't heard anything to suggest that LG has fixed the problem.

There are also compatibility issues with some brands of eARC capable AV receivers such as Denon's 2017 range.

Radox-0 · 25 Sep 2020 at 03:35

lucid said:
There are (at least) a couple of problems. LG seems to have had a long-running issue with how it has implemented the handshake between devices using ARC. It doesn't affect everything, but users are reporting issues with certain equipment combinations and Dolby Digital 5.1 when HDMI CEC is enabled which is what's required to get ARC working.

There are also some problems with eARC too. These are different. eARC uses the redundant connections that should have been used for HDMI Ethernet support rather than sharing the data channels of other connections. This means that CEC doesn't need to be switched on for eARC to work. However, with DD5.1 again, there are reports of significant lip sync issues (this is also reported for ARC).

Other issues include LG's version of eARC not supporting PCM 5.1 and PCM 7.1 audio, so games consoles that use PCM send uncompressed HD audio run in to a brick wall. This seems to be an error of omission, but I haven't heard anything to suggest that LG has fixed the problem.

There are also compatibility issues with some brands of eARC capable AV receivers such as Denon's 2017 range.

Did the PCM element not got solved natively with the CX and most recent fix for C9? I know prior to that PCM signals did not do multichannel via eARC to my AVR, but with recent update was resolved AFAIK? My HTPC using GTX1080Ti can address my 7.1 setup via the TV via eARC fine. https://www.flatpanelshd.com/news.php?subaction=showfull&id=1591857596 unless you mean something else (possible not the most upto date with TVs).

ahhh yeah, guess i have been fortune on the compatability side in that case with my bits in terms of lip sync and just working fine (touch wood). Always good to hear what still may be broken.

lucid · 25 Sep 2020 at 12:44

TBH, it's not something I spend a lot of time worrying about, you know, wondering and researching whether or not LG has fixed their own audio problems. All I really need to be is aware of the issues and how it might affect certain source signal and equipment combos. There's only so much time in a day, and only so many quirks and niggles that it's possible to keep in mind when planning installations or specifying gear.

They may well have fixed some stuff in later model releases, but have they done that for the older products too?

Radox-0 · 25 Sep 2020 at 12:50

lucid said:
TBH, it's not something I spend a lot of time worrying about, you know, wondering and researching whether or not LG has fixed their own audio problems. All I really need to be is aware of the issues and how it might affect certain source signal and equipment combos. There's only so much time in a day, and only so many quirks and niggles that it's possible to keep in mind when planning installations or specifying gear.

They may well have fixed some stuff in later model releases, but have they done that for the older products too?

Ahh yeah was only pointing that portion out as for me LPCM was important and great when it rolled out for the exact use cases you mentioned. Depends what you mean by older products, its been rolled out to all of last years 2019 models and is on the 2020 models.

lucid · 25 Sep 2020 at 14:23

Radox-0 said:
Ahh yeah was only pointing that portion out as for me LPCM was important and great when it rolled out for the exact use cases you mentioned. Depends what you mean by older products, its been rolled out to all of last years 2019 models and is on the 2020 models.

It was more of a general point encompassing all of the audio problems that LG have been having rather than the specific ones that are solely of interest to you.

Obviously eARC and its associated problems are a fairly recent development, but there are models going back to 2015 when people were spending £3000 and up for an OLED. It would be nice to see some support for them, particularly an update to WEB OS 2.0 on the 6 series panels.

Radox-0 · 25 Sep 2020 at 17:51

lucid said:
LG have been having rather than the specific ones that are solely of interest to you.

Not sure what you mean by specific ones solely of interest to me? You were the one who mentioned LPCM and not being aware of a fix. I only highlighted that they did, nothing more nothing less. That feature is actually of interest to plenty of people buying consoles and the shed loads more recently using HTPC's and Ampere GPUs with these TV's.

In regards to TV going years back, not been interested in this for long, but learned already buy as is and anything more is a bonus. Going to be left upset from what I have seen if you set expectations which while would be nice, not something I bank on. Those spending 3k on OLEDs back in the day were early adopters for which there is always going to be a premium.

Anyways going off topic, as I say was highlighting they did resolve the LPCM element on recent models including C9 which OP has.