What Is the BK-104A?

The OREI BK-104A is an 8K 1x4 HDMI 2.1 splitter with audio extraction. It takes one HDMI source and duplicates the same audio/video signal to up to four HDMI displays at the same time, while also providing separate optical and analog audio outputs.

The HDMI source connects to HDMI IN, and up to four TVs, monitors, projectors, or displays connect to HDMI OUT 1 through HDMI OUT 4. Audio can also be extracted through the OPTICAL port or the L/R 3.5mm stereo output.

The BK-104A supports HDMI 2.1, HDCP 2.3 / 1.4, 48Gbps FRL bandwidth, 18Gbps TMDS bandwidth, resolutions up to 8K@60Hz 4:2:0 12-bit, 8K@30Hz 4:4:4 12-bit, and 4K@120Hz 4:4:4 12-bit. It also supports HDR, HDR10, HDR10+, Dolby Vision, HLG, VRR, ALLM, QMS, QFT, SBTM, advanced EDID management, automatic downscaling, HDR-to-SDR conversion, and audio extraction through optical and analog outputs. The application diagram shows one DVD or Blu-ray player connected to HDMI IN, 8K TVs connected to HDMI outputs, an audio amplifier connected to OPTICAL, and 2.0 speakers connected to L/R.

The BK-104A is useful for 8K TVs, 4K@120Hz gaming displays, home theaters, AV receivers, soundbars, powered speakers, game consoles, Blu-ray players, conference rooms, digital signage, and commercial AV installations where one HDMI source needs to be shown on up to four displays with separate audio output.

IMPORTANT — BK-104A Is a 1x4 HDMI Splitter with Audio Extraction

The BK-104A duplicates one HDMI source to four HDMI outputs and can extract audio separately.

This product mirrors one HDMI source. It does not create independent video outputs and does not extend a PC desktop across four screens.

IMPORTANT — Supports 8K@60Hz and 4K@120Hz

The BK-104A supports high-bandwidth HDMI 2.1 video formats.

To get 8K@60Hz, 8K@30Hz, or 4K@120Hz, the HDMI source, HDMI cables, displays, and selected EDID mode must all support the required signal.

IMPORTANT — HDMI 2.1 Gaming Features

The BK-104A supports several HDMI 2.1 gaming and video features.

These features depend on the HDMI source, game console or PC, display, HDMI cable, and EDID setting.

IMPORTANT — Automatic Downscaling Is Supported

The BK-104A supports automatic downscaling and conversion on all outputs.

It can downscale:

1. 8K to 4K
2. 8K to 1080p
3. 4K to 1080p 
    
   Before downscaling, the splitter compares the EDID information from the connected displays and selects the minimum resolution needed to downscale and output.

IMPORTANT — Automatic HDR-to-SDR Conversion Is Supported

The BK-104A supports automatic HDR-to-SDR conversion on all outputs.

This is useful when one display supports HDR and another display only supports SDR.

Auto Downscaling and Conversion Examples

The manual shows examples of how the BK-104A handles mixed display setups.

The manual also notes that if the source is downscaled and converted to 1080p DVI according to the display EDID, that output will not have sound.

IMPORTANT — Downscaling Limitations

Downscaling will not work in these conditions:

If downscaling does not work, reduce the source resolution, change the HDMI output format, or select a compatible EDID setting.

IMPORTANT — DVI Output Has No Sound

If the BK-104A converts the signal to 1080p DVI based on a connected display’s EDID, that output will not carry sound.

This is expected because DVI does not carry HDMI audio.

If a TV unexpectedly receives DVI output:

1. Try a different HDMI input on the TV
2. Replace the HDMI cable
3. Restart the source and splitter
4. Try a different EDID setting
5. Confirm the display reports HDMI audio support

Advanced EDID Management

The BK-104A includes a three-position EDID DIP switch with eight settings.

A switch in the UP position represents 1. 
A switch in the DOWN position represents 0.

Understanding Copy EDID Mode

DIP code 111 copies the connected output display EDID. This is the factory-default setting.

Use this mode when:

1. You want the source to follow the connected display capability
2. The main display supports the desired resolution and audio format
3. You want automatic negotiation based on connected display EDID
4. You are unsure which fixed EDID setting to use 
    
   If other displays have lower capability, automatic downscaling and HDR-to-SDR conversion may adjust their output.

Selecting an EDID Mode

The manual does not provide additional guidance for choosing between FRL12G and FRL10G. Use the setting that is compatible with your HDMI source, displays, and HDMI cables.

After changing EDID, restart or reconnect the HDMI source if it does not renegotiate automatically.

IMPORTANT — Audio Extraction Is Supported

The BK-104A includes optical and analog audio extraction.

HDMI audio also passes through the HDMI outputs.

Supported HDMI Audio

The BK-104A supports HDMI audio pass-through formats including:

The selected EDID setting determines whether the source outputs 2.0CH, 5.1CH, or 7.1CH audio.

Supported Optical Audio

The OPTICAL output supports:

Use OPTICAL for digital audio devices such as soundbars, AV receivers, audio amplifiers, or digital audio processors.

Supported Analog Audio

The L/R analog output supports:

If the 3.5mm analog output does not produce sound, set the HDMI source audio output to PCM, LPCM, or Stereo.

IMPORTANT — Optical and Analog Audio Have Limits

Use HDMI to a compatible AV receiver if you need advanced audio formats such as Dolby Atmos, Dolby TrueHD, or DTS-HD Master Audio.

IMPORTANT — This Model Does Not Support CEC

The manual’s FAQ states that turning off all displays with a single TV remote is not possible because this model does not support CEC.

If CEC control is required, use a model that specifically lists CEC support.

Ports and Panel Layout

Step-by-Step Setup

1. Connect the HDMI source device to HDMI IN on the BK-104A. 
   Examples include a Blu-ray player, game console, streaming device, cable box, satellite receiver, desktop PC, laptop, DVR, NVR, or media player.
2. Connect the main display to HDMI OUT 1.
3. Connect HDMI OUT 2, HDMI OUT 3, and HDMI OUT 4 to additional displays as needed.
4. Connect OPTICAL to a soundbar, AVR, amplifier, or digital audio device if digital audio extraction is needed.
5. Connect L/R to powered speakers or an analog stereo audio device if stereo analog audio is needed.
6. Set the EDID DIP switch.
7. For default EDID behavior, use DIP code 111.
8. Connect the included DC 5V/2A power adapter.
9. Power on the HDMI source, displays, splitter, and audio equipment.
10. Check that the Power LED is on.
11. Check the IN LED to confirm the source is detected.
12. Check OUT 1–4 LEDs to confirm connected displays are detected.
13. Test video, refresh rate, HDR/SDR behavior, HDMI audio, optical audio, and L/R audio.

HDMI Cable Requirement — Critical

Use the correct HDMI cable for the resolution being used.

For 8K and 4K@120Hz, use certified Ultra High Speed HDMI 2.1 cables.

Poor or unsuitable HDMI cables may cause:

1. No video
2. Flickering
3. Black screen
4. One output not working
5. 8K@60Hz not working
6. 4K@120Hz not working
7. HDR issues
8. VRR issues
9. HDCP handshake issues
10. Audio dropouts 
     
    For troubleshooting, test each HDMI cable directly between the source and display.

Power Requirement — Critical

The BK-104A uses a DC 5V/2A power adapter.

Use the included power adapter or a compatible replacement with the correct voltage, polarity, connector, and current rating.

Understanding the Application Example

The application diagram shows:

1. DVD or Blu-ray player connected to HDMI IN
2. 8K TV 1 and 8K TV 4 connected to HDMI outputs
3. Audio amplifier connected to OPTICAL
4. 2.0 speakers connected to L/R
5. Power supply connected to DC 5V 
    
   This demonstrates the main use case: one HDMI source shown on up to four HDMI displays while audio is extracted to external audio equipment.

Package Contents

The package includes:

HDMI, optical, and 3.5mm audio cables are not listed as included.

Supported Video and Audio

The BK-104A supports video formats including:

Supported HDMI audio formats include:

Supported extracted audio formats include:

Supported Technical Specifications

What Source Devices Is the BK-104A Compatible With?

The BK-104A is compatible with HDMI source devices such as:

1. 8K media players
2. 4K Blu-ray players
3. DVD players
4. Streaming devices
5. Cable boxes
6. Satellite receivers
7. HDMI 2.1 game consoles
8. Gaming PCs
9. Desktop PCs
10. Laptops with HDMI output
11. DVRs
12. NVRs
13. AV receiver outputs
14. HDMI switch outputs
15. HDMI matrix outputs 
     
    The source must output a supported HDMI format.

What Displays Is the BK-104A Compatible With?

The BK-104A can connect to HDMI displays such as:

1. 8K TVs
2. 4K@120Hz TVs
3. 4K TVs
4. 1080p TVs
5. Gaming monitors
6. Computer monitors
7. Projectors
8. Commercial displays
9. Digital signage displays
10. Classroom displays
11. Conference room displays
12. Home theater displays 
     
    Automatic scaling and HDR-to-SDR conversion help support mixed-resolution and mixed-HDR display setups.

What Audio Devices Is the BK-104A Compatible With?

The BK-104A can connect to audio devices such as:

1. AV receivers
2. Soundbars with optical input
3. Amplifiers
4. Digital audio processors
5. Powered speakers
6. Analog stereo systems
7. 3.5mm audio devices 
    
   Use OPTICAL for digital audio and L/R for analog stereo audio.

Frequently Asked Questions

Q: What is the OREI BK-104A used for? 
A: It is used to split one HDMI source to up to four HDMI displays while also extracting audio through optical and analog outputs.

Q: Is the BK-104A a splitter or extender? 
A: It is an HDMI splitter. It does not extend HDMI over CAT cable by itself.

Q: How many HDMI inputs does it have? 
A: It has one HDMI input.

Q: How many HDMI outputs does it have? 
A: It has four HDMI outputs.

Q: Does it show the same content on all displays? 
A: Yes. All connected displays show the same HDMI source.

Q: Can it show different content on each display? 
A: No. It duplicates one HDMI input to all outputs.

Q: Can it extend my computer desktop across four screens? 
A: No. The manual states that this splitter only mirrors a laptop or PC screen and does not extend the PC display.

Q: Does the BK-104A support 8K@60Hz? 
A: Yes. It supports up to 8K@60Hz 4:2:0 12-bit.

Q: Does it support 8K@30Hz? 
A: Yes. It supports 8K@30Hz 4:4:4 12-bit.

Q: Does it support 4K@120Hz? 
A: Yes. It supports up to 4K@120Hz 4:4:4 12-bit.

Q: Does it support HDMI 2.1? 
A: Yes. It is HDMI 2.1 compliant.

Q: What HDCP version does it support? 
A: It supports HDCP 2.3 and HDCP 1.4.

Q: What video bandwidth does it support? 
A: It supports 48Gbps FRL bandwidth and 18Gbps TMDS bandwidth.

Q: Does it support HDR? 
A: Yes. It supports HDR, HDR10, HDR10+, Dolby Vision, and HLG.

Q: Does it support VRR and ALLM? 
A: Yes. VRR and ALLM are listed as supported.

Q: Does it support QMS, QFT, and SBTM? 
A: Yes. These HDMI 2.1 features are listed as supported.

Q: Does it support downscaling? 
A: Yes. It supports 8K to 4K and 8K / 4K to 1080p automatic downscaling.

Q: Does it support HDR-to-SDR conversion? 
A: Yes. Automatic HDR-to-SDR conversion is supported on all outputs.

Q: Can I connect mixed 8K, 4K, and 1080p displays? 
A: Yes. The splitter supports mixed display setups using automatic downscaling and HDR-to-SDR conversion.

Q: When does downscaling not work? 
A: Downscaling does not work when the input source is 8K DSC format or when the input resolution is not supported by the splitter.

Q: What happens if the signal is converted to 1080p DVI? 
A: The manual notes that if the source is downscaled and converted to 1080p DVI according to display EDID, that output will not have sound.

Q: What is the factory-default EDID mode? 
A: DIP code 111, which copies the connected output sink EDID.

Q: Which EDID setting supports 4K60 4:4:4 with stereo audio? 
A: Use DIP code 110.

Q: Which EDID settings support 8K HDR? 
A: DIP codes 101, 100, 011, 010, 001, and 000 support 8K HDR modes with different FRL and audio selections.

Q: Does the BK-104A support Dolby Atmos? 
A: Yes. Dolby Atmos is listed as supported through HDMI audio pass-through.

Q: Does it support DTS-HD Master Audio? 
A: Yes. DTS-HD Master Audio is listed as supported through HDMI audio pass-through.

Q: Does it support DTS:X? 
A: DTS:X is not specifically listed in the BK-104A manual.

Q: Does it extract audio to speakers? 
A: Yes. It has optical and 3.5mm analog audio extraction outputs.

Q: What audio does the optical output support? 
A: Optical output supports LPCM / Dolby / DTS 5.1CH.

Q: What audio does the analog L/R output support? 
A: Analog L/R output supports LPCM 2CH.

Q: Why is there no sound from the L/R output? 
A: Set the HDMI source audio output to PCM, LPCM, or Stereo.

Q: Can optical output Dolby Atmos? 
A: Dolby Atmos is not listed for optical output. Use HDMI to a compatible AVR for advanced audio formats.

Q: Does it support ARC or eARC? 
A: ARC and eARC are not listed.

Q: Does it support CEC? 
A: No. The FAQ states that this model does not support CEC.

Q: Can I turn off all displays with one TV remote? 
A: No. The manual states that this is not possible because the model does not support CEC.

Q: Does it support IR control? 
A: IR control is not listed.

Q: Does it support RS-232? 
A: RS-232 control is not listed.

Q: What power adapter does it use? 
A: It uses a DC 5V/2A power adapter.

Q: What is the maximum power consumption? 
A: Maximum power consumption is 6W.

Q: What HDMI cable should I use for 8K? 
A: Use an Ultra HDMI 2.1 cable up to 3m / 10ft.

Q: What HDMI cable length is recommended? 
A: The manual lists 3m / 10ft for 8K, 8m / 26ft for 4K60, 12m / 39ft for 4K24, and 15m / 49ft for 1080p. The FAQ recommends high-quality HDMI 2.1 cables under 30ft.

Q: What should I do if there is no video output? 
A: Check that HDMI cables are plugged in correctly, try changing HDMI cables, check if the front LEDs are lighting, and try a lower resolution from the source device.

Q: What should I do if one display has no video? 
A: Check that display’s HDMI cable, selected input, power, and OUT LED. Also test the display on another HDMI output.

Q: What should I do if 8K@60Hz or 4K@120Hz does not work? 
A: Confirm the source, displays, EDID mode, and HDMI cables support the required format. Use Ultra High Speed HDMI 2.1 cables for 8K and 4K@120Hz.

Q: Does the BK-104A need external power? 
A: Yes. Connect the included DC 5V/2A multinational power supply.