HDMI audio extractor chip with I2S pinout

[mavelazquez1983]

I'm looking to feed I2S from HDMI audio or specifically the ARC port of newer televisions to a Twisted Pear B3pro. After looking around a while I realized there's nothing out there (that I could find) diy wise that could do it. So I knew there were plenty of audio extractor boxes, most of them were toslink. If I was going to compromise I would use coax spdif out from one of these boxes. I had one of these from Amazon basics that cost $20 and it did the job well feeding my receiver for a few years. I decided to take the cover off and see what was insideView attachment 1084986

I looked up the chip inside and found out that it is made by this company
https://www.semiconn.com/ep92a3e

The cool thing is that is has I2S output but I could not locate a data sheet to see what and where those pins might be. I've sent an email to that company to see if they'll send me one. If someone knows where to find it please post it.

What's even better is this set of pads labeled JR1 has the right amount of pads for I2S. Could this be I2S? The unit in question is here

https://www.amazon.com/AmazonBasics-Audio-Stereo-Extractor-Converter/dp/B07KRWYN4R/ref=sr_1_1_sspa?crid=1CD2F4FRBU141&keywords=hdmi+audio+extractor&qid=1661568784&sprefix=hdmi+audio+extractor,aps,117&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFRSFkyS0NVMUdXODYmZW5jcnlwdGVkSWQ9QTA2ODc1OTIyQ0pZM0UyVlNUR1I0JmVuY3J5cHRlZEFkSWQ9QTA0MjczMDMyUUFISE82S0UxVjZSJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

View attachment 1084989

I don't have the knowledge or tools to try and figure out what JR1 is. Does anyone have a schematic of this unit? I would think it's mass produced under several makers and models.

Any thoughts? Help?

Hello, I hope you all have already figured out that those 5 pins are for the JTAG connector to program the Chip

 

[sbelyo]

I sort of abandoned this as I sold the DAC I was going to use

 

[MRamone]

Hello, I hope you all have already figured out that those 5 pins are for the JTAG connector to program the Chip

the question is who has the information necessary to program it

 

[yomav]

Good find - so if the 3E has the same pinout as the 2E then on the JR1 connector :

pin1 ??? Not used (maybe power?)
pin2 SCK
pin3 GND
pin4 SD
pin5 WS

This is making the assumption that the track disappearing under the IC goes to pin94. Definitely worth looking with a 'scope.

So I'm using display port. So was thinking. I could get a display port splitter. Then use a display port to HDMI converter. Then run that thru an HDMI audio extractor. Then the output on the extractor goes to my receiver. Would this give me HDMI audio without a second display showing up in windows?

 

[uriy-ch]

Yes, it works. You have 8 outputs but accessing them by pair is not guaranteed. It will depend on how the OS manages the outputs.
I can push noises on all channels independently with any DAWs tho.

Do I understand correctly that this board acts as an I2S master?

 

[PureBasic]

It’s a I2S master only IIRC but don’t take my words for granted. I haven’t looked at this board since years.

 

[phofman]

Since HDMI signal is a clock master, running the I2S interface as slave would require some asynchronous reclocker to align the HDMI and external I2S master clocks. Very unlikely to be a part of such device.

 

[uriy-ch]

As I understand it, in order for such an extractor to be able to extract sound, the smart TV needs to have an HDMI ARC output that can be connected to this extractor.
But it is not entirely clear whether this extractor will be able to extract sound if it is connected between the TV box and the TV.

 

[phofman]

In standard HDMI the audio is part of the combined stream and must be extracted from the stream. In ARC the audio is passed as an SPDIF stream via separate wires.

I do not know what model you mean, but e.g. EP92A2P (I cannot find datasheet for EP92A3) can output HDMI audio to I2S and SPDIF, while ARC audio only to SPDIF:

 

[uriy-ch]

I do not know what model you mean

I'm talking about this extractor. But I don't know what chip it's made on.
https://www.aliexpress.us/item/3303...rPageLogUid=7jDVsa3LModU&gatewayAdapt=glo2usa

In ARC the audio is passed as an SPDIF stream via separate wires.

What format is the multichannel stream in or is it only stereo?

 

[phofman]

What format is the multichannel stream in or is it only stereo?

eARC supports many channels (do not know the number exactly). Nice description is https://www.graniteriverlabs.com/en-us/technical-blog/hdmi-earc-compliance-test . The audio signal is transferred via the same HEAC +/- differential pair, encoding is standard IEC 60958-1.

I do not know what chip that model uses, but my 2 cents the eARC stream is just passed onto the digital coax output.

 

[MRamone]

I'm talking about this extractor. But I don't know what chip it's made on.
https://www.aliexpress.us/item/33031920347.html?spm=a2g0o.productlist.0.0.13d86a459DB94Z&algo_pvid=133e4260-2eb4-47fc-b1f8-7c63d23b5063&algo_exp_id=133e4260-2eb4-47fc-b1f8-7c63d23b5063-3&pdp_ext_f={"sku_id":"67365152884"}&pdp_npi=2@dis!USD!38.99!35.87!!!!!@2103143616619644037023691e20c3!67365152884!sea&curPageLogUid=7jDVsa3LModU&gatewayAdapt=glo2usa

What format is the multichannel stream in or is it only stereo?

The device you link is not earc capable. Could be -i don't know- that it passes undecoded compressed 5.1 channels via ARC through optical/coax.
The device below is earc capable: it takes earc multichannel and outputs multichannel via hdmi.

US $42.42 | 192KHz HDMI Audio eARC Extractor Converter 7.1CH 4K 60Hz eARC TV Projector supported HDMI ONLY Toslink Coaxial Converter

https://a.aliexpress.com/_Ez7h2ag

In theory you could do:
TV earc > device I linked > hdmi > device you linked > multichannel i2s.
But I never tried it.
Another possibility is to open the device I linked and tap the i2s signals that run between the input and output chip. I show the internals and another guy reported having done it successfully here:

https://audiosciencereview.com/foru...erything-you-know-about-hdmi-earc-here.55559/

 

[uriy-ch]

Another possibility is to open the device I linked and tap the i2s signals that run between the input and output chip.

If the receiver decodes HDMI audio, then of course inside this receiver the signal to its DACs goes via I2S, and they can be intercepted by opening the receiver, I understand that.

But I want to find some ready-made product that can pins output I2S, from eARC or from HDMI TV box, but without modernization, like I2S output the device I gave earlier.

 

[MRamone]

"ready-made product that can pins output I2S, from eARC"
I have never seen such device, unfortunately.