[mythtvnz] Kernel updates with TBS tuners -> HDHomeRun

[criggie]

On 1/11/18 9:58 PM, Stephen Worthington wrote:
> > "100baseTX high-speed network"
> So it only has 100 Mbit/s Ethernet.  So with four tuners, each recording multiple HD channels at once, you would be using a significant percentage of the 100 Mbit/s bandwidth.So I would want
> to have each Quatro on its own Ethernet card, if I was directly connecting them to a card.

I can't find NZ data, but here's some overseas info

Ofcom plans to put 4x HD 720p channels on mux B. The total bandwidth is 
27.2 Mbit/s which gives us 6.8 Mbit/s per channel. Ofcom say that this 
is mitigated by a 15% stat mux gain which gives us 7.82 Mbit/s per channel.
>From 
http://www.bbc.co.uk/blogs/bbcinternet/2009/06/whats_happening_with_freeview.html


24 Mbit/s used to carry actual content.
>From 
https://forums.digitalspy.com/discussion/344453/hd-channel-bandwidth 
seems to be UK again



and
For HD programmes, the BBC use H.264 coding, with an average bitrate of 
3.2Mbps and 192 kbps audio.
HD programmes use about 1.5 gigabytes per hour of video.
from http://www.astra2sat.com/televison/tv-bitrates/


To summarise, each channel is using under 10 Mbit of data all the time.  
So a 100 Mbit link should handle 10 channels at once.  Your points about 
gigabit being 10x 100 Mbit are fine and valid and I concur.


>   And they could use a better protocol that had error recovery.

Why?  You're not moving precious bits, you're moving live streaming TV.  
Its not supposed to be perfect, its supposed to be on-time.

If your local LAN is losing enough frames to cause issues, then changing 
to an error recovery protocol will make it even more delayed in local 
transmission.  This would be worse than losing the odd bit.


> The other major problem to watch out for is that their wall-wart power supplies always fail with age, and they also cause strange problems as
> they start failing, so it can take ages to work out what the problem is.  If I was ever to buy a SiliconDust device, I would consider
> replacing the power supply immediately with a known good one.

This is reasonable.  It would be perfectly okay to run a 12V line from a 
molex plug out the back of the case, then into an adapter and into your 
hdhomerun.



-- 

Criggie

http://criggie.org.nz/

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ourshack.com/pipermail/mythtvnz/attachments/20181102/bd09ac9f/attachment.html>