Re: Somewhat OT: MythTV / DVB in Israel
2012/1/14 Udi Finkelstein linux...@udif.com On Fri, Jan 13, 2012 at 11:50 AM, Shachar Shemesh shac...@shemesh.bizwrote: On 01/12/2012 02:27 PM, Udi Finkelstein wrote: yielding about 30% higher bitrate for the same bandwidth Complete and utter nitpicking. If you nitpick, make sure your are correct first... Bitrate is the number of bits per second (usually measured in kilo bits per second, or kbps, or sometimes mbps). This means that bit rate and bandwidth are, for all practical purposes, one and the same. I meant every word I said. And your assumption that bitrate and bandwidth is the same is definitely wrong! Every heard the of the distinctions between baud and bit/s? Just look at the evolution on modems from the 110bps half duplex to the 53600 full duplex (57600 is cheating because it relies on a digital line, so its not fail to compare it with earlier standards). As for DVB-T2, I will not go into the technical details , but feel free to look at: http://en.wikipedia.org/wiki/DVB-T2#System_differences_with_DVB-T What you (probably) meant to say was that the new encoding allows transferring the same video quality for 30% less bit rate. Sorry, wrong again... Unlike earlier DVB-T efforts in the world (e.g. UK's Freeview) that used MPEg2, The Israeli standard already used H.264 over the DVB-T physical layer from day one. The new transmissions will keep H.264 but will use the new DVB-T2 encoding for the HD channels. Udi ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il In general. the maximum bit rate which can go through a channel is its analog bandwidth, multiplied by log2 of the ratio of signal to noise (plus one, but usually that's negligible). i.e if you have 1Mhz analog bandwidth and your signal energy is 128 times your noise energy (what we call 7x3=21 DB), you get to a maximum theoretical of 1Mhz x 7 = 7 Mbps. why is that: if you take a signal and change it 1 million times a second - you will be transferring 1 million symbols a second, and will be using 1MHZ bandwidth. now lets say a symbol can be any amplitude between 0 and 127 (because the difference between levels must be bigger then the noise), then we can encode 7 bits per symbol, for a total of 7Mbit per second. i do not know of DVB-T. but if i compare DVB-S (2 bit per symbol) and DVB-S2 (usually 3 bits per symbol) - you see that DVB-S2 is more sensitive to noise but have x1.5 bitrate. there are other considerations: we need error correction. for that we pay, a simple example: we can send every bit three times, so if we have error, we still can take a majority vote and know the right value for the bit. this is of course a very not effective error correction scheme, it is a rate 1/3 (we use triple bandwidth). btw DVB-S2 has also a better error correction scheme. another consideration is the gap, either time domain, or frequency domain. for example: i have two channels. as analog filters has a transition region, between what they let pass and what they block, we need a gap which takes some analog bandwidth. just my 2c ( and 1$ experience ;-)) erez. ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On Jan 15, 2012, at 2:13 PM, Erez D wrote: Unlike earlier DVB-T efforts in the world (e.g. UK's Freeview) that used MPEg2, The Israeli standard already used H.264 over the DVB-T physical layer from day one. The new transmissions will keep H.264 but will use the new DVB-T2 encoding for the HD channels. The real question is which tuner cards/USB sticks will have DVB-T2 standard modems in them and which will only decode the DVB-T standard? Will any of them be supported by Linux? Geoff. -- Geoffrey S. Mendelson, N3OWJ/4X1GM My high blood pressure medicine reduces my midichlorian count. :-( ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On 01/12/2012 02:27 PM, Udi Finkelstein wrote: yielding about 30% higher bitrate for the same bandwidth Complete and utter nitpicking. Bitrate is the number of bits per second (usually measured in kilo bits per second, or kbps, or sometimes mbps). This means that bit rate and bandwidth are, for all practical purposes, one and the same. What you (probably) meant to say was that the new encoding allows transferring the same video quality for 30% less bit rate. Shachar -- Shachar Shemesh Lingnu Open Source Consulting Ltd. http://www.lingnu.com ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On 01/12/2012 10:08 PM, Steve Litt wrote: What do you guys think about Mythbuntu? I like the idea that it just works (supposedly). I installed mythbuntu a couple of years ago. It was so much the opposite of just works that, to this day, both me and my wife record by setting the Yes receiver to automatically switch to the right station (via the usual order a viewing of a show), while independently telling the computer to record at the same time. The script used literally does little more than at starttime cat /dev/video0 program.mpg; at stoptime killall cat. In fact, the only other thing is loading a bunch of settings to the encoder via v4l. Now, if someone has a script for setting up mythtv with Yes and configuring the blaster, I'd love to have it. I got stuck at the EPG stage and never got past it, and frankly, we're kinda used to our existing system, stone aged though it undoubtedly is. Shachar -- Shachar Shemesh Lingnu Open Source Consulting Ltd. http://www.lingnu.com ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On Thu, Jan 12, 2012 at 10:08 PM, Steve Litt sl...@troubleshooters.comwrote: On Thursday, January 12, 2012 07:21:31 AM Ohad Levy wrote: I'm a mythtv user, and I used to use the DVB-T broadcast in Israel, the quality of the broadcast depends a lot of where you live. What do you guys think about Mythbuntu? I like the idea that it just works (supposedly). mythtv NEVER just-works. don't care what distro. Thanks SteveT * My new 99 cent Kindle book : http://www.amazon.com/dp/B006QTBLA2 * * Steve Litt : http://www.troubleshooters.com * . ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
Hi Shachar,
On Fri, Jan 13, 2012 at 11:50:42AM +0200, Shachar Shemesh wrote:
On 01/12/2012 02:27 PM, Udi Finkelstein wrote:
yielding about 30% higher bitrate for the same bandwidth
Complete and utter nitpicking.
Some more nitpicking.
Bitrate is the number of bits per second (usually measured in kilo bits
per second, or kbps, or sometimes mbps). This means that bit rate and
bandwidth are, for all practical purposes, one and the same.
Not exactly. Bandwidth is a signal processing term. Udi, thus, refers to the
spectral bandwidth. See
http://en.wikipedia.org/wiki/Bandwidth_%28signal_processing%29.
What you (probably) meant to say was that the new encoding allows
transferring the same video quality for 30% less bit rate.
I think Udi meant to say that with the new encoding you can have 30% more bps,
or digital bandwidth, while using the same spectral bandwidth, or RF
bandwidth.
baruch
--
~. .~ Tk Open Systems
=}ooO--U--Ooo{=
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Somewhat OT: MythTV / DVB in Israel
Hi all, I'm about to cancel my incredibly expensive HOT Triple and get Internet-only instead. I'm not that bothered about TV but I do have a MythTV box lying around from the old country, and I'd be happy to see if I could get it working here. It would just need a PCI tuner card or two. As I see it in Israel there are terrestrial, cable, and satellite options. I don't have any terrestrial aerial or satellite dish connection in my flat, so I'd be much happier to use the cable connection if I can (see below). Questions to start with: 1) If I was to cancel my HOT subscription for television, are any channels at all provided over the cable for free? As a reference point, in the UK, if you cancel your Sky satellite subscription, a limited number of channels are still available, unencrypted, over the satellite link and set-top-box. 2) If not, if I went for terrestrial, does anybody know of a DVB-T PCI card that works with Linux and the broadcast standard in Israel? (I understand it's MPEG-4 / H.264.) If I needed to get a terrestrial aerial fitted to the building, is that government-subsidized (don't laugh, it is in some countries IIRC)? Antony ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On 01/12/2012 10:44 AM, Antony Gelberg wrote: Hi all, I'm about to cancel my incredibly expensive HOT Triple and get Internet-only instead. I'm not that bothered about TV but I do have a MythTV box lying around from the old country, and I'd be happy to see if I could get it working here. It would just need a PCI tuner card or two. As I see it in Israel there are terrestrial, cable, and satellite options. I don't have any terrestrial aerial or satellite dish connection in my flat, so I'd be much happier to use the cable connection if I can (see below). Questions to start with: 1) If I was to cancel my HOT subscription for television, are any channels at all provided over the cable for free? As a reference point, in the UK, if you cancel your Sky satellite subscription, a limited number of channels are still available, unencrypted, over the satellite link and set-top-box. no. if you disconnect from the cable company's TV service - you don't get any channels from *them* any longer. 2) If not, if I went for terrestrial, does anybody know of a DVB-T PCI card that works with Linux and the broadcast standard in Israel? (I understand it's MPEG-4 / H.264.) If I needed to get a terrestrial aerial fitted to the building, is that government-subsidized (don't laugh, it is in some countries IIRC)? normally, you won't need any large antenna in order to receive DVB-T channels. in the worst case - you'll by a small active antenna to place on top of the tv - at least that's what is being advertised (and it works for me - i live inside a valley where the default tiny antenna that comes with the DVB-T doesn't work). as for a PCI card - i don't have an idea, but note one thing: the government made a decision to use a different type of broadcast in their future HD broadcasts, then the one originally assumed - check this before you buy any DVB-T equipment. --guy ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
as for a PCI card - i don't have an idea, but note one thing: the government made a decision to use a different type of broadcast in their future HD broadcasts, then the one originally assumed - check this before you buy any DVB-T equipment. Do you have any information about this? All I can find is that the number of channels was to be expanded from 5 to 12 and then a few weeks later the expansion was to be to 18. Details were few, they article said the original 5 would remain free (as in no monthly cost above your yearly TV tax), while the additional ones would be subscription. The articles I did find said the additional channels may be HDTV but the original hardware will support it. The original standard used (4:3) 520i, can be decoded with a 1.6gHz ATOM processor, the higher resolution standards will require a faster processor. It's hard to guess what MYTHTV needs, as you may be able to set it to save the video without decoding. Geoff. -- Geoffrey S. Mendelson, N3OWJ/4X1GM My high blood pressure medicine reduces my midichlorian count. :-( ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On Thu, Jan 12, 2012 at 12:18 PM, guy keren c...@actcom.co.il wrote: On 01/12/2012 10:44 AM, Antony Gelberg wrote: Hi all, I'm about to cancel my incredibly expensive HOT Triple and get Internet-only instead. I'm not that bothered about TV but I do have a MythTV box lying around from the old country, and I'd be happy to see if I could get it working here. It would just need a PCI tuner card or two. As I see it in Israel there are terrestrial, cable, and satellite options. I don't have any terrestrial aerial or satellite dish connection in my flat, so I'd be much happier to use the cable connection if I can (see below). Questions to start with: 1) If I was to cancel my HOT subscription for television, are any channels at all provided over the cable for free? As a reference point, in the UK, if you cancel your Sky satellite subscription, a limited number of channels are still available, unencrypted, over the satellite link and set-top-box. no. if you disconnect from the cable company's TV service - you don't get any channels from *them* any longer. 2) If not, if I went for terrestrial, does anybody know of a DVB-T PCI card that works with Linux and the broadcast standard in Israel? (I understand it's MPEG-4 / H.264.) If I needed to get a terrestrial aerial fitted to the building, is that government-subsidized (don't laugh, it is in some countries IIRC)? normally, you won't need any large antenna in order to receive DVB-T channels. in the worst case - you'll by a small active antenna to place on top of the tv - at least that's what is being advertised (and it works for me - i live inside a valley where the default tiny antenna that comes with the DVB-T doesn't work). I'm a mythtv user, and I used to use the DVB-T broadcast in Israel, the quality of the broadcast depends a lot of where you live. for example, in Ra'aana it was really bad reception, buying active (amplified) antenna's did not help much, and I did get the best quality using a 40cm directional passive antenna, but sadly that was not enough for WAF. Saying that, a friend of mine who lives in Ramat Gan, got it to work with just putting his finger where the antenna socket is. I heard that you can buy a one meter antenna or something, and that should be good enough, but I did not follow on it further, maybe someone here knows where you can buy such antennas. besides that, after mythtv is working (including EPG), you realize you can only see 10,11 and 22 (there are others that are not so relevant). Ohad as for a PCI card - i don't have an idea, but note one thing: the government made a decision to use a different type of broadcast in their future HD broadcasts, then the one originally assumed - check this before you buy any DVB-T equipment. --guy ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On Thu, Jan 12, 2012 at 1:35 PM, geoffrey mendelson geoffreymendel...@gmail.com wrote: as for a PCI card - i don't have an idea, but note one thing: the government made a decision to use a different type of broadcast in their future HD broadcasts, then the one originally assumed - check this before you buy any DVB-T equipment. Do you have any information about this? All I can find is that the number of channels was to be expanded from 5 to 12 and then a few weeks later the expansion was to be to 18. The decision was to use the new DVB-T2 standard for future HD broadcasts, (I assume they will keep the current SD broadcasts on the existing DVB-T channel). DVB-T2 uses a different encoding than DVB-T yielding about 30% higher bitrate for the same bandwidth, or so are the claims. This is very similar to the DVB-S vs DVB-S2 migration. As for MythTV for DVB-T on linux, try searching the www.hometheater.co.ilforums. I think there are people doing that there. udi ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On 2012 1 12 14:37, Udi Finkelstein linux...@udif.com wrote: On Thu, Jan 12, 2012 at 1:35 PM, geoffrey mendelson geoffreymendel...@gmail.com wrote: as for a PCI card - i don't have an idea, but note one thing: the government made a decision to use a different type of broadcast in their future HD broadcasts, then the one originally assumed - check this before you buy any DVB-T equipment. Do you have any information about this? All I can find is that the number of channels was to be expanded from 5 to 12 and then a few weeks later the expansion was to be to 18. The decision was to use the new DVB-T2 standard for future HD broadcasts, (I assume they will keep the current SD broadcasts on the existing DVB-T channel). DVB-T2 uses a different encoding than DVB-T yielding about 30% higher bitrate for the same bandwidth, or so are the claims. This is very similar to the DVB-S vs DVB-S2 migration. The difference between dvb-s and s2 are big. A dvb-s pci card would not support s2. However what done in Israel on dvb-t was To take the same protocol and just replace the mpeg2 with h264. So it is possible that A regular dvb-t card will support the Israeli broadcasts. (Still need to verify) As for MythTV for DVB-T on linux, try searching the www.hometheater.co.ilforums. I think there are people doing that there. udi ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On Jan 12, 2012, at 2:46 PM, Erez D wrote: The difference between dvb-s and s2 are big. A dvb-s pci card would not support s2. However what done in Israel on dvb-t was To take the same protocol and just replace the mpeg2 with h264. So it is possible that A regular dvb-t card will support the Israeli broadcasts. (Still need to verify) Thanks, That's a codec issue. The DVB-T signal still remains the same. The data streams (MPEG-TS) still are the same with different video encoding. This is not unusual, the original DVB-T transmissions, long ago, far, far away, were MPEG-2 encoded. Israel was one of the first, if not the first, country to adopt MPEG-4 encoding and definitely the first to use AAC (MPEG-4) audio encoding. How that will affect the first generation Israeli DVB-T box I have is a question for speculation at this point. What it does mean is that a PC using a DVB-T tuner/dongle will not be able to decode the new channels without a better CPU than the minimum needed now. Geoff. -- Geoffrey S. Mendelson, N3OWJ/4X1GM My high blood pressure medicine reduces my midichlorian count. :-( ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Somewhat OT: MythTV / DVB in Israel
On Thursday, January 12, 2012 07:21:31 AM Ohad Levy wrote: I'm a mythtv user, and I used to use the DVB-T broadcast in Israel, the quality of the broadcast depends a lot of where you live. What do you guys think about Mythbuntu? I like the idea that it just works (supposedly). Thanks SteveT * My new 99 cent Kindle book : http://www.amazon.com/dp/B006QTBLA2 * * Steve Litt : http://www.troubleshooters.com * . ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
