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Miracast has been described as "HDMI over WiFi"†, and as such I've recommended it to a couple of people asking about HTPC setups when unable to run wire.

After giving it more thought, I'm wondering a couple of things:

  1. Is this a really lossless signal?
  2. How does latency affect sound output not coming from the TV/receiver (coming from the HTPC)?

†: "A rough description would be “HDMI over Wifi” and in fact the setup is modeled closely to the HDMI standard."; para 2

Community
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Louis Waweru
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  • Reviewers: This question is on-topic for Super User as it involves an HTPC. – bwDraco Apr 23 '15 at 05:39
  • Of course it isn’t lossless. HDMI has over 3 GBit/s of bandwidth. There’s simply no such WiFi standard. – Daniel B Apr 23 '15 at 05:45
  • @DanielB Yikes! I was expecting some invention to compress that data being *mirac*le of it... – Louis Waweru Apr 23 '15 at 06:26
  • @DanielB However, the data begin transmitted over HDMI is completely uncompressed, 24-bit per color data (there are variations on this). That data can probably be compressed quite a bit. – Steve May 01 '15 at 19:38

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According to Wikipedia,

Miracast is "effectively a wireless HDMI cable, copying everything from one screen to another using the H.264 codec and its own digital rights management (DRM) layer emulating the HDMI system".

So, no, the Miracast protocol is not the same as HDMI, assuming this statement is correct. The HDMI data is sampled and compressed (H.264), transmitted to the received, and decoded back to HDMI. This also means that the compression is lossy.

Steve
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