[Live-devel] High bit-rate (CBR) 4K streaming over a wireless link ...

[Shyam Kaundinya]

Hi

My product involves streaming high bit rate (>15M) 4K video over a high-bit rate wireless link. I use LIVE555 proxy server on both sides. Based on reviewing the forum articles, I have made the following changes, to accommodate the high bit rate and an unreliable link.


1. I replaced all occurances of

increaseReceiveBufferTo
and
sysctl net.core.rmem_max = the_maximum_buffer_size_that_you_need
with a large size value.

Re: the_maximum_buffer_size_that_you_need
What’s a good value to use here for 4K CBR at high-bit rate (>15M) ? 4K max uncompressed size is = 4096*2160*3=26,542,080. That seems somewhat excessive. I am not sure if using any other value would just be totally arbitrary. Is there a guaranteed minimum compression that a H.265 encoder can guarantee irrespective of what the scene is ? If so, I can arrive at my buffer size based on that information.


1. Do I need to also modify the

increaseSendBufferTo

and
sysctl net.core.rmem_max = the_maximum_buffer_size_that_you_need
as well to match the receivebuffer ?


1. At times I see significant latency on the Rx side. But when I disconnect and reconnect the client, it seems to go away. If I leave it running, the virtual memory used by live keeps on increasing steadily and then live crashes and exits. Any thoughts on what could cause this behavior ?

Regards
Shyam

[Shyam Kaundinya]

Oops! Typo here


#2 should read 

Do I need to also modify the

increaseSendBufferTo

and
sysctl net.core.wmem_max = the_maximum_buffer_size_that_you_need
as well to match the receivebuffer ?


From: Shyam Kaundinya <***@digitalforcetech.com>
Date: Tuesday, August 28, 2018 at 8:07 AM
To: "live-***@lists.live555.com" <live-***@lists.live555.com>
Subject: High bit-rate (CBR) 4K streaming over a wireless link ...

Hi

My product involves streaming high bit rate (>15M) 4K video over a high-bit rate wireless link. I use LIVE555 proxy server on both sides. Based on reviewing the forum articles, I have made the following changes, to accommodate the high bit rate and an unreliable link.


1. I replaced all occurances of

increaseReceiveBufferTo
and
sysctl net.core.rmem_max = the_maximum_buffer_size_that_you_need
with a large size value.

Re: the_maximum_buffer_size_that_you_need
What’s a good value to use here for 4K CBR at high-bit rate (>15M) ? 4K max uncompressed size is = 4096*2160*3=26,542,080. That seems somewhat excessive. I am not sure if using any other value would just be totally arbitrary. Is there a guaranteed minimum compression that a H.265 encoder can guarantee irrespective of what the scene is ? If so, I can arrive at my buffer size based on that information.


1. Do I need to also modify the

increaseSendBufferTo

and
sysctl net.core.rmem_max = the_maximum_buffer_size_that_you_need
as well to match the receivebuffer ?


1. At times I see significant latency on the Rx side. But when I disconnect and reconnect the client, it seems to go away. If I leave it running, the virtual memory used by live keeps on increasing steadily and then live crashes and exits. Any thoughts on what could cause this behavior ?

Regards
Shyam