How to synchronize 2 streams ?

[JPingouix]

Hello,
I hope I am in the right forum... If not, please tell me where to go.

I have a Raspberry Pi (i.e. like a PC running Linux Debian) playing audio files to its standard output: a Yamaha sound bar on its HDMI output.
In the same time, it sends the stream on http port 8080, so another Raspberry (PC, or Sonos, or something else) is able to catch and play it in another room.
Of course, there is a delay of a few seconds between the local and the remote sound. I am not able to found a way to avoid it. It would be fine to put some delay after sending the stream on the LAN and before playing it on the HDMI output, has anyone any idea how to do it ?
Thanks in advance for any help!

[JPingouix]

I have found just a beginning of solution: I launch 2 cvlc:

- The 1st one sends stream to http 8080, but NOT to HDMI.
- The second one reads the stream from localhost:8080 and sends it to "display" (i.e. HDMI)

This is acceptable on another Raspberry Pi, but the sound on Sonos remains a few seconds in late. I don't know how to put a delay in the second stream to avoid it.