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# 19046 3-Feb-2008 11:09
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Hi all, I need some help to work out the best way to get satellite and streaming internet content to my lounge 42" HDMI telly.
I have some cabling challenges to overcome to achieve this, in that there is only 1 x RG7 coax feed carrying RF from a 6-way splitter co-located with my satellite receiver (a Sky decoder permanently tuned to Prime, as our house is one of those not able to 'see' the local TVNZ transmitter site (Te Aroha)). On the feeder side of the splitter, the terrestrial and satellite signals are combined on the same coax in the ceiling space, and then split out at the satellite decoder in the cupboard where the 6 way splitter is. The decoded prime signal is then re-combined onto the splitter on a different UHF channel (38) to feed all the TV outlets in the house. So, in short, I do have TV1,TV2, TV3, C4 and Prime at all TV outlets. (Incidentally, the Prime service for those who can't get it terrestrially is free off Sky after you have had the dish/decoder installed.)

The other problem I have is that the location of my wireless ADSL router is not located  near the splitter. The house is not cabled for ethernet either, which would be too difficult to install to the lounge where the HDMI telly is (Pana 700 series 42" plasma), unfortunately. A wireless option is possible between the ADSL router location and the TV splitter cupboard, and to other locations in the house, but see my later comment about quality of that option..

So what am I trying to achieve? I want to be able to deliver Freeview (off sateliite, coz I can't get a terrestrial signal of Te Aroha), and streaming internet content to the 42" plasma in the lounge, (preferably at HDef when available). I had planned to build a MythTV backend co-located  with the satellite receiver (so I can chain the satellite signal through a DVB-S card in the Myth TV box), pump internet content into the same box using 802.11g wireless connection from my ADSL router, and then deliver the  MythTV-managed content over wireless 802.11g to a frontend PC connected by HDMI to the plasma in the lounge.

But based on testing I've done so far, I'm concerned I won't be able to always maintain a good enough link to deliver an uninterrupted video stream between the backend and the frontend in the lounge. Although there is a possibility that the 'blocky' transmission I've seen (i.e a burst of video, then a pause, then another burst etc) is more to do with bottlenecks in my test server (1.2GHz processor with 768MB RAM)  than the wireless link (802.11g @ ~20MBps)? Is it reasonable to assume I should be able to maintain a good enough link over 11g? Even when I probably still have to halve my available wireless throughput as my test setup is streaming directly from a backend at the router location?

The only other option I can think of is to re-modulate the MythTV video output back onto the RF coax, rather than transport it over IP, but this seems a bit of a backward step. Anyone know whether MythTV can be configured to do that (i.e all content (not just decoded TV) out on a TV-out output? Maybe needs a separate video card?).

Or do I just have to forget about streaming internet, buy a standard freeview decoder, co-locate it with the Sky decoder, and sort out a remote control extender to change the channels from the lounge without having to go to the cupboard all the time?

Anyone else had to resort to these extremes? (Next time, I better buy a house that I can cable more easily!)

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  # 108277 3-Feb-2008 11:36
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Firstly what is stopping you running cat5e cable to the lounge? If you've got a concrete floor then running it under the house obviously isn't an option. Running cable down walls can be difficult but it can be done - was the existing coax run by somebody or installed when the house was built?

WiFi isn't great for streaming video as you have discovered and to be completely honest I would try and run cable rather than relying on WiFi for video.


So what am I trying to achieve? I want to be able to deliver Freeview (off sateliite, coz I can't get a terrestrial signal of Te Aroha), and streaming internet content to the 42" plasma in the lounge, (preferably at HDef when available). I had planned to build a MythTV backend co-located  with the satellite receiver (so I can chain the satellite signal through a DVB-S card in the Myth TV box), pump internet content into the same box using 802.11g wireless connection from my ADSL router, and then deliver the  MythTV-managed content over wireless 802.11g to a frontend PC connected by HDMI to the plasma in the lounge.



Freeview off DVB-S won't be in HD anyway, it will only be in SD. The DVB-T broadcasts will be in HD.

The other option could be to combine the recombine the sat feed on the coax running to the TV and split it there which would mean you could have the MythTV box sitting next to the TV with the DVB-S card. This would obviously depend on the signal levels you can get and with all the wiring at present may post some issues.



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  # 108281 3-Feb-2008 12:09
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From my experience WiFi is useless at streaming, even audio can have issues. Its one thing to surf or download files where small breaks in transmission are not noticed, but a few secounds break is a lot of video frames.

Where there is a will there is a way, as Steve said, someone got the coax (RG6 not 7) there in the first place, so you must be able to get a cat5e in.

Edit, is there a phone point at the site of the TV, if the house is a recent build that is probably cat5e, if so where does it go, could you patch it back.

Cyril

 
 
 
 


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  # 108340 3-Feb-2008 18:36
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cyril7: From my experience WiFi is useless at streaming, even audio can have issues.
Cyril


Ditto with Cyril on this. Transmission breaks just don't seem accceptable  when streaming audio or video. My experience is Wi-Fi just gets knocked out occasionally with interference such as Microwaves, even some vehicles passing by...



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  # 108503 4-Feb-2008 15:33
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Thanks for the replies. Yes, I agree wired would be best, so I will probably have to look for a serious way of achieving that, but it ain't gonna be easy. To transport my satellite RF signal to the TV location, I'm gonn a need another pair of TV+Satellite splitter/combiners and probably a satelite RF in-line amp. Any recommendations for a good source and brand? Will this still give me a decent signal/noise given that I will need to extend the distance between my LNB and the Decoder by probably another 25-30m? 

Notwithstanding my particular situation, has anyone ever done what I mused? i.e re-'broadcast' MythTV over RF? Can MythTV do this using the TV-Out port available on some graphics cards?  

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  # 108633 5-Feb-2008 11:20
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I think the biggest problem with streaming over wi-fi is that it is normally done over UPD rather than TCP. I don't think it's really a bandwidth problem. UDP just blindly sends the packets though the air, there is no re-transmits for packets that don't make it there, Of course some packets will be lost in the air.

In the case of a video conference UDP (realtime) really is necessary but not with streaming 1-way media. I hope projects like mediaportal TVServer and and myth will create options to allow TCP for playing media. i.e. a "When clients xx connect use TCP" option. Not sure how this would be implemented. But as an example, try sharing (windows file sharing) your timeshifting folder, start  a channel and try playing the timeshift file off the share (which uses TCP) and I'll bet it plays fine, assuming you have a good wireless connection.




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  # 108696 5-Feb-2008 14:33
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I'm gonn a need another pair of TV+Satellite splitter/combiners and
probably a satelite RF in-line amp. Any recommendations for a good
source and brand? Will this still give me a decent signal/noise given
that I will need to extend the distance between my LNB and the Decoder
by probably another 25-30m?


How long is the currrent cable, it is possible to withstand 20-30dB cable/splitter loss (3dB/10meters, 2way splitter 5dB, 11dB 4way) without resorting to an amplifier. An amp should only be used if you have dropped to below 50dBuV or there abouts, if the quality/BER figure is still ok then dont add an amp. If you must add an amplifier then a 10dB one is all most applications require, 20dB is often too much and will cause overloading issues. DSE has a 10dB amp L4697, and 20dB L4698, but dont get one till you have clearly established you can get by with out it.

Cyril

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  # 108701 5-Feb-2008 14:50
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I can stream using my DM500 over TCP over Wifi with a good reception (~10 meters to the AP and one wall inbetween!).  I did however need a updated streamts module to improve the streaming, otherwise streaming TV3 off Freeview did create choppy recordings.  On my DM600 I have had flawless streaming using the modules included in the image, plus recording over the network to a windows share.

I still firmly believe cabling UTP & RG6 around the house is the way to go, it makes life easier.





 
 
 
 


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  # 109019 7-Feb-2008 10:31
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You could consider Ethernet over power - some products claim capability of 200Mbps, though this is dependent oin your wiring etc.

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  # 109024 7-Feb-2008 10:49
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There is a standard for Ethernet over powerline, and you can get speeds of 85 or 200Mb/s, however my experience with this technology is that once again is very prone to frame losses, so fine for non streaming applications, however not so ideal for streaming.

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  # 109196 7-Feb-2008 23:01
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Yeah, the powerline ethernet things retrain all the time when line conditions chance so  if you turn something on or off it gets a gap in transmission, and there seems to be no recovery of it at the lower levels so if you are using UDP then its just gone.

I have some of the old 14 meg ones and they only work when on the same phase, same is true for teh 85 meg ones from the limited testing I have done, would assume that its the case for the 200 meg ones too.




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  # 109212 8-Feb-2008 06:29
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Have not tried any of the older ones, but the 200Meg one I have works well with a dreambox, file copies are around the 60-70Mbit/sec and whilst streaming I've had no issues at all. YMMV.




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  # 109471 9-Feb-2008 13:02
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Cyril7, I've checked that I can extend my satellite signal over the existing RG6 to the TV and it works with the addition of a 10dB amplifier. After much mucking around, I've also now managed to find a way to install a Cat 5e cable between my router location and the TV splitter. Getting Cat5e to the lounge still remains a challenge without resorting to running a cable around the outside of the house. Ceiling access is impossible without ripping the roof off, sub floor access is similarly difficult (polished wooden floor boards laid over concrete), and exterior walls are textured plaster, which I don't want to compromise the watertightness of by drilling through.

The IP over AC idea I may try out longer term, but for now, I've decided to leave trying to get Cat5e into the lounge, and will simply co-locate a single Myth frontend/backend at the TV splitter location.

So my question now swings back to how to best feed the video output of the MythTV box back onto the RG6 TV cable. i.e in the same way that a Satellite decoder, PVR box or standard VCR would do.

Is there are a TV capture card available that  produces modulated TV output i.e has an antenna in/TV out loop through? Or am I best to run S-Video or DVI into a separate external VCR and use that device to mix the MythTV signal back with the standard TV channels?

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  # 109620 10-Feb-2008 11:49
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garryk,
I have used VCR as a modulating device satisfactorily but it does have the drawback that it is another "intelligent" device in the chain. If the power gets interrupted for example, the VCR is likely to drop the AV setting and you loose the signal until someone remembers to go set the VCR to the appropriate AV in setting. I prefer to use a dedicated modulator (available from Clipsal or Hills for round $120)

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  # 109639 10-Feb-2008 13:31
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garryk:

Is there are a TV capture card available that produces modulated TV output i.e has an antenna in/TV out loop through? Or am I best to run S-Video or DVI into a separate external VCR and use that device to mix the MythTV signal back with the standard TV channels?


No point running anything better then composite out to a modulator since thats all you get out the other end of it.

And I have never being able to get a noise free picture when mixing the modulator output with the off air signals because of all the noise coming in on the antenna.

So at best all you will have out the other end is a lousy composite signal with mono sound and quite possibly a grainy picture.

Add to that limitation in resolution that RF has over a direct connection and you will struggle to read anything smaller then 20pt on the screen, and forget working widescreen since there was no support on any tv out I have tried.




Richard rich.ms

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