Hello folks,
I try to find if it is possible to tap the digital signal from a hdmi cable.
No Im not interested in low signal levels and whatnot, im aware of these issues.
What is interesting is :
-Is it a clean PCM signal ?
-Is it a I2S signal ?
-Considered the TMDS (+/-/gnd), i guess one of these(TMDS 0/1/2) three, carry the audio.
I guess the signal is different depending on if it is DTS-HD / Dolby Digital / 5.1PCM or other. But what do I need to bring pure stereo or raw format into a chip/unit ?
I try to find if it is possible to tap the digital signal from a hdmi cable.
No Im not interested in low signal levels and whatnot, im aware of these issues.
What is interesting is :
-Is it a clean PCM signal ?
-Is it a I2S signal ?
-Considered the TMDS (+/-/gnd), i guess one of these(TMDS 0/1/2) three, carry the audio.
I guess the signal is different depending on if it is DTS-HD / Dolby Digital / 5.1PCM or other. But what do I need to bring pure stereo or raw format into a chip/unit ?
Welcome to the New World Order. Everything on the HDMI link is encrypted, to make sure you don't record it to make pirate copies. The fact that every bluray ever produced is available for free on bittorrent because bluray has been cracked to death is just extra irony.
If you want to extract useful data from it, you'll have to scrape it from the outputs of an HDMI decoder blessed with the Secret Key, for example in a receiver or TV.
If you want to extract useful data from it, you'll have to scrape it from the outputs of an HDMI decoder blessed with the Secret Key, for example in a receiver or TV.
NeTV Starter Pack ID: 609 - $119.00 : Adafruit Industries, Unique & fun DIY electronics and kits
Explanation: FPGA sitting between HDMI input and HDMI output doing MITMA.
Explanation: FPGA sitting between HDMI input and HDMI output doing MITMA.
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This worked for me:
Ligawo 6518985 HDMI Matrix 4x2 - 1080p 3D Toslink Coax 3,5mm Audio Audio & Video Gerte Matrix Switch Splitter HDMI Matrix Switch
Sony Bluray player converting DSD to PCM -> HDMI cable -> Ligawo splitter -> coax cable -> Rotel RSX 1056.
Rotel showing "176.4 kHz LPCM" and playing music.
Don't know why the signal is not encrypted...
My tv was connected to HDMI ouput of the splitter. Maybe this is needed for the HDCP protocol?
Must try, if this runs without TV connected...
Best regards
Ligawo 6518985 HDMI Matrix 4x2 - 1080p 3D Toslink Coax 3,5mm Audio Audio & Video Gerte Matrix Switch Splitter HDMI Matrix Switch
Sony Bluray player converting DSD to PCM -> HDMI cable -> Ligawo splitter -> coax cable -> Rotel RSX 1056.
Rotel showing "176.4 kHz LPCM" and playing music.
Don't know why the signal is not encrypted...
My tv was connected to HDMI ouput of the splitter. Maybe this is needed for the HDCP protocol?
Must try, if this runs without TV connected...
Best regards
I have what is probably internally this same box (made by port-ta), and it works fairly well, though it doesn't decode formats like Dolby/ac3 or dst. It just strips whatever audio signal is being carried in the HDMI signal and converts it to optical, coax, and analog. (In other words, if your source can pass such a signal to the output, and your audio device doesn't have a decoder, then what comes out of the audio ports of the switch sounds like pure noise.)
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