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Newbie
Newbie
383 Views
Registered: ‎07-16-2020

HDMI 16-bit and 20-bit PCM audio support

I am looking to the Xilinx HDMI receiver and transmitter spec (pg235-v-hdmi-tx-ss.pdf and pg236-v-hdmi-rx-ss.pdf) and I am unable to find out if 16-bit and 20-bit audio is supported. In both spec, the AXI interface for PCM and non-PCM data has 24-bit of data (table 7). No where in the spec they talk about the audio format on the HDMI interface. In table 1 they say that audio sample packets (0x02) are supported without giving any limitation. For the output, there should be a way to tell the module which formats to output. I have not found the info.

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Xilinx Employee
Xilinx Employee
318 Views
Registered: ‎08-02-2007

@jostiguy 

Please see the latest PG236 Table 7 : https://www.xilinx.com/support/documentation/ip_documentation/v_hdmi_rx_ss/v3_1/pg236-v-hdmi-rx-ss.pdf

[27:4] Audio sample word for L-PCM/3D-Audio

[27:12] Audio sample word for HBR

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Newbie
Newbie
290 Views
Registered: ‎07-16-2020

Thanks. I saw in table 7 that 16-bit for HBR was supported. But there is no mention if 16-bit and 20-bit for PCM is supported.

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Xilinx Employee
Xilinx Employee
272 Views
Registered: ‎08-02-2007

@jostiguy 

It's mentioned in the paragraph before table 7 : The audiointerface transports 24-bits L-PCM or 16-bits HBR audio samples

For L-PCM audio type, the data bits are always 24 bits. Let me double check if 16-bit or 20 bit PCM is supported or not.

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Xilinx Employee
Xilinx Employee
245 Views
Registered: ‎08-02-2007

@jostiguy 

I've confirmed we support upto 24 bits for L-PCM & 3D Audio, 16 bits for HBR

Note : The L-PCM (Packet Type 0x02 and 0x0B) allows you to pack up to 24 bits of audio from the Audio Data Stream. The HBR (Packet Type 0x09) allows you to pack up to 16 bits of audio from the Audio Data Stream

So 16 bit and 20 bit should be supported

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Newbie
Newbie
239 Views
Registered: ‎07-16-2020

In input how do we know if the PCM samples are 24-bit, 20-bit or 16-bit?

In ouput how do we specify if the PCM samples are 24-bit, 20-bit or 16-bit?

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Xilinx Employee
Xilinx Employee
141 Views
Registered: ‎08-02-2007

@jostiguy 

You can check that with Channel Status. The 196 bit info that comes with the audio frame.

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