TIVO TX20: NEBIE- Can you get Digital channels or just analog with antenna?
lbbss
understand what it can do. I would like to record free tv shows from
my antenna to hard drive. I have been told that it can only record
in std deff. But my question is, does it have a atsc digital tuner,
which then converts it to std deff when recording, is this correct?
Now all the U.S. channels are digital only. I read this model has
free subscription, does that come through the air waves by means of
antenna?
Or is it more the case that this tivo has no tuner at all, so the only
tv you can get with it, is through the free subscription, and no
channels from local tv station (Buffalo and toronto).
Pardon my ignorance on the tivo, thanks for the help.
Doug McIntyre
>I am looking to buy this tivo tx20 (used). But want to make sure I
>understand what it can do. I would like to record free tv shows from
>my antenna to hard drive. I have been told that it can only record
>in std deff. But my question is, does it have a atsc digital tuner,
>which then converts it to std deff when recording, is this correct?
>Now all the U.S. channels are digital only. I read this model has
>free subscription, does that come through the air waves by means of
>antenna?
Hmm, TX20 doesn't really ring any bells, but googling it, Toshiba has
a RS-TX20 model that must be what you are talking about. So not a box
made by TiVo, but more of the old-school partner type box.
AFAIK, only the TiVo made Series3 models (ie. S3 & TiVo HD/XL) have
ATSC tuners and are the only high-def ones. The older boxes had NTSC
tuners, but the spec sheet of this one implies it doesn't even have an
NTSC tuner.
Its made to be hooked up to the output of a cable tuner, or a
standalone tuner box. It would have to control that via an IR blaster,
so this box would have to know the control codes for that tuner box to
be useful (so checking compatibility would be necessary for you to
make sure things work the way you want).
There isn't any integrated boxes that I know of that would downrez an
ATSC signal and record it in std-def. You could hookup an external
ATSC tuner that puts out std-def signals, but I don't know of any
integrated ones.
The Free subscription is "TiVo Basic". That means you can record based
on channel and time of day, much like a VCR. It won't do any of the
fancy TiVo things like record by program name or wishlists or anything
like that, so it doesn't need to download anything "over the air".
I wouldn't pay much for this box, certainly not the $600 that the one
Amazon seller wants. It sounds like a TiVoHD would be a better fit for
you if the price is comparable if you want to record shows over the air now.
(amazon reseller wants $175 for one used). You would have to do the
subscription thing with that box, but thats true for just about any
thing that does recordings based on a program guide.
lbbss
not clear on how you get the free subscription, by way of an antenna,
it has to get to you somehow? Or does a subscription not mean tv
channels, but more of a tv guide, but not the actual tv program.
When you have a cable subscription, it comes to you through a physical
cable wire to your house. So how do you get the tivo free
subscription? I do have a external tuner box, that can convert to
std def. and the Tivo tv guide, I don't care about. I just want free
channels. This person is selling it for $30, but she does not know
how they work, so I can't as here about it. thanks again.
Gordon Burditt
>not clear on how you get the free subscription, by way of an antenna,
>it has to get to you somehow? Or does a subscription not mean tv
>channels, but more of a tv guide, but not the actual tv program.
A subscription gets you functioning software and guide data. It
does not get you TV signals. (In much the same way, a subscription
to the dead-tree edition of TV Guide magazine does not include a
television set, an antenna, or a cable feed.)
You can get TV signals in various ways, none of which have anything
to do with a TiVo subscription:
- Over the air, with a converter box.
- From a cable subscription (cable box)
- From a satellite subscription (box)
In order for your rs-tx20 to control the channel, it needs to be
able to control the associated box, usually by generating remote-control
IR signals, and it needs to know the codes for whatever that box
is.
>When you have a cable subscription, it comes to you through a physical
>cable wire to your house. So how do you get the tivo free
>subscription? I do have a external tuner box, that can convert to
>std def. and the Tivo tv guide, I don't care about. I just want free
>channels. This person is selling it for $30, but she does not know
>how they work, so I can't as here about it. thanks again.
If you only want channels, and do not need to record, connect the
box to the TV and forget about the TiVo. If you do want to record,
get the TiVo (or some other recorder), but it does not arrange
delivery of TV signals.
Wes Newell
Don't waste your time with this. There are a few commercial HDTV (OTA
ATSC 8VSB) recorders available that you can buy. I haven't looked at any
lately as I use a PC with 3 dual ATSC tuners in it that allows me to
record up to 30 shows at once (although I've never recorded more than 6).
Guide data is sent with each digital broadcast, so there's really no need
to subscribe to any guide data (although I pay $20 a year for a 14 day
guide service). There are lots of options for ATSC recorders, but the
best by far is to use a PC. It's cheaper and much more versatile.
--
Want the ultimate in free OTA SD/HDTV Recorder? http://mythtv.org
My Tivo Experience http://wesnewell.no-ip.com/tivo.htm
Tivo HD/S3 compared http://wesnewell.no-ip.com/mythtivo.htm
AMD cpu help http://wesnewell.no-ip.com/cpu.php
Peter Pan
news:6d8dc845-56ba-4b24...@a32g2000yqm.googlegroups.com...
Only has an analog tuner built in, but can get video from a cable box (have
used mine with DTV, dish, FIOS, and now comcast), use an ir blaster for
control, the guide is 3 days worth of info that either comes via dial-up or
if you have a wireless network can use that instead... does do one cool
thing, you can play and/or burn standalone dvd's (I record stuff and then
burn dvd's for my sister to watch on her elcheapo dvd player, handy since i
have hbo/starz/etc) ... some (not all) have a server built in (wireless
network and browser lets you xfer stuff to/from it, handy if you want to
download stuff off the internet and play it on your tv)
biggest bummer on my old unit is the hard disk is dying, but for $30, hey
why not......
lbbss
signal that way (antenna connects to tv, from tv out to tivo). Can
the tivo accepts a digital signal and convert it to std def for
recording purpose?
Doug McIntyre
I've never seen a TV that converted ATSC in and put out any signal on
the jacks. They all are inputs, not outputs.
Of course, the signal is there internally somewhere, but the only way
to get at it would be to tap into the internal circuits of the TV and
bring it out safely and properly.
Peter Pan
news:4b0ea7ae$0$33857$8046...@newsreader.iphouse.net...
some tv's have a vcr out jack, you may want to look for that....
Peter Pan
you have a friggen plasma tv, but ONLY use it for Over The Air Stuff? no box
(cable, sat, even converter for the hundreds more hd channels)
why do you insist on using rf?
Wes Newell
> "lbbss" <lab...@yahoo.com> wrote in message
> news:cec6a65f-b489-4cde-
a1e6-6f5...@v30g2000yqm.googlegroups.com...
>> What about hooking up my plasma tv to the tivo and getting the tv
>> signal that way (antenna connects to tv, from tv out to tivo). Can
>> the tivo accepts a digital signal and convert it to std def for
>> recording purpose?
>
> you have a friggen plasma tv, but ONLY use it for Over The Air Stuff? no
> box (cable, sat, even converter for the hundreds more hd channels) why
> do you insist on using rf?
Maybe because that's how you hook up an antenna to a TV, and it's a free
HDTV source. I get 56 channels here free. Out of them I only actually
record from about 12 of them. But from just those I record about 10-12
hours a day. More than I could watch without a DVR.
JEDIDIAH
Much better signal quality.
Assuming he's got a nice strong signal coming from his antenna, he's going
to get a much better result from his over the air channels. They are going
to be at full/original resolution and not downgraded. Cable companies love
to re-compress the signals they redistribute. It lets them shove more of
them onto whatever bandwidth they have.
Most of what's on "cable" is not going to showcase what an HD plasma TV can do.
Quite a bit of the "need" for HD with cable is artificially generated by crap SD signals.
--
In a "stable" but "inconsistent" system, the end user only |||
has to adapt once rather than needing to adapt any time a / | \
new version of the relevant shovelware is released.
lbbss
knows nothing about technical stuff. If she has cable or satellite
tv, can I connect it with it from the cable to the tivo, and from the
tivo to the tv both with a coax cable? What do I do after that, just
plug the power and see if a menu comes up. Then it likely is ok?
She said it work when her ex last used it, but selling it as is, feel
free to test it out. Any advise on how to do a bare minimum test?
Thanks.
Doug McIntyre
Yes, just booting it up and making sure you see it boot and can get to
the menu and/or watch live video through it should be test enough.
The only other thing would see if it crashes over time, but if it
boots up, it should be working well enough for you.
GMAN
>On Wed, 25 Nov 2009 18:44:54 -0800, lbbss wrote:
>
>> thanks for that info. Yes, that is a toshiba rs-tx20. I am still not
>> clear on how you get the free subscription, by way of an antenna, it has
>> to get to you somehow? Or does a subscription not mean tv channels,
>> but more of a tv guide, but not the actual tv program. When you have a
>> cable subscription, it comes to you through a physical cable wire to
>> your house. So how do you get the tivo free subscription? I do have
>> a external tuner box, that can convert to std def. and the Tivo tv
>> guide, I don't care about. I just want free channels. This person is
>> selling it for $30, but she does not know how they work, so I can't as
>> here about it. thanks again.
>
>Don't waste your time with this. There are a few commercial HDTV (OTA
>ATSC 8VSB) recorders available that you can buy. I haven't looked at any
>lately as I use a PC with 3 dual ATSC tuners in it that allows me to
>record up to 30 shows at once (although I've never recorded more than 6).
>Guide data is sent with each digital broadcast, so there's really no need
>to subscribe to any guide data (although I pay $20 a year for a 14 day
>guide service). There are lots of options for ATSC recorders, but the
>best by far is to use a PC. It's cheaper and much more versatile.
>
>
>
Wes Newell
> How are 6 tuners getting you 30 recordable channels at once?
Each tuner receives the full bandwidth of each channel. So, with one
tuner, you can record up to 5 sub-channels since all five are in the same
bandwidth. If Tivo had a lick of sense, they would have incorporated this
into their recorders like the software I use does. Maybe they'll come out
with a software upgrade for it if you ask, but I doubt it. Like I said, I
don't use this feature since in my area all the networks have their own
stations, but in other areas stations broadcast more than one major
network. Southern OK is a good example where one station broadcast 3
major networks and another broadcast 2. Two tuners could record all 5 at
once. There are many stations that broadcast 5 sub-channels, and 2 tuners
could record all 10 at once. Just one more reason, besides cost, not to
use a Tivo-HD for OTA.
Spider Dawg
Each tuner can record a different channel, and each channel can have 5
program streams. With my hdHomerun, using the command line software that
ships with it, the usual 3-step procedure is: 1) a command to set the
channel 2) a command to set the program, and 3) a command to save to
disc. By skipping step 2, it will record the whole transport stream as
one file, and when playing back the video with VLC, mplayer, etc I can
switch between programs similar to an 8-track audio tape (yes, I'm that
old). It can also easily be split into one or more individual files.
Now, just because it *can* be done, I've never actually done it other
than for testing purposes. I don't watch nearly that much tv, and with
the command line software I use it's basically one or all, can't do just
2 or 3.
Jim
Bill Kearney
>>record up to 30 shows at once (although I've never recorded more than 6).
>>
It's just more fantasy (ie lies) from Wes.
The only way you'd get more than 6 recordings from 6 ATSC tuners would be if
each station had 5 subchannels on it and you wanted to record each of them.
Very few (if any) markets have ATSC stations with that many active
subchannels, let alone any programming worth recording from them.
Peter Pan
yes, but......
in the post you ask about sat/cable, the rf from those boxes are usually
analog (ch 3 or 4, and so they work on older tv's), but in the subject
(before the hyphen) you ask about a tx20 (it has analog rf tuner), but
(after the hyphen) you ask if you can get just digital OR just analog with
an antenna (most antennas can do both) so your q is a bit confusing..
if however, you want to use an antenna to receive outside signals, use the
rf instead of video on the tivo, and want them converted to analog for free,
consider getting a digital to analog converter box.... many were free when
broadcast stations went to digital...
Wes Newell
You call me a liar, and then turn around and prove yourself wrong.
Brilliant Bill. Your stupidity is only exceeded by your ego.:-)
I suppose your car will only do 70MPH because that's the speed limit. And
there's only 2 apples in a bushel because you can only hold one in each
hand. You're a riot.:-)
Peter Pan
news:slrnhh0kp1.4bi....@linux-dfkc.site...
> On 2009-11-27, GMAN <winnie...@100acrewoods.com> wrote:
>> In article <helchr$221$2...@news.eternal-september.org>, Wes Newell
>> <w.ne...@invalid.invalid> wrote:
>>>On Wed, 25 Nov 2009 18:44:54 -0800, lbbss wrote:
>>>
>>>> thanks for that info. Yes, that is a toshiba rs-tx20. I am still
>>>> not
>>>> clear on how you get the free subscription, by way of an antenna, it
>>>> has
>>>> to get to you somehow? Or does a subscription not mean tv channels,
>>>> but more of a tv guide, but not the actual tv program. When you have a
>>>> cable subscription, it comes to you through a physical cable wire to
>>>> your house. So how do you get the tivo free subscription? I do have
>>>> a external tuner box, that can convert to std def. and the Tivo tv
>>>> guide, I don't care about. I just want free channels. This person is
>>>> selling it for $30, but she does not know how they work, so I can't as
>>>> here about it. thanks again.
>>>
the guide is just that, a guide only, and comes via a dial-up or network
connection... not extra free channels.....
JEDIDIAH
>
>
>>> I use a PC with 3 dual ATSC tuners in it that allows me to
>>>record up to 30 shows at once (although I've never recorded more than 6).
>>>
>> How are 6 tuners getting you 30 recordable channels at once?
>
> It's just more fantasy (ie lies) from Wes.
>
> The only way you'd get more than 6 recordings from 6 ATSC tuners would be if
> each station had 5 subchannels on it and you wanted to record each of them.
I record stuff on my OTA _3 channels on a pretty regular basis actually.
I would not be surprised if I were to enable multirec and I ended up with
more than 1 show recording per tuner. Then there's the odd situation where
there's more than one "real" channel on a particular frequency. My area has
at least one of those.
> Very few (if any) markets have ATSC stations with that many active
> subchannels, let alone any programming worth recording from them.
>
With unencrypted QAM that would be pretty mundane.
--
It's a great paradox. |||
/ | \
Mac users aren't supposed to be capable of organizing their
own files with the Finder or browse the storage on a digital
camera yet they can be expected to track down their own QT
extensions with no real help from Apple.
GMAN
>On Fri, 27 Nov 2009 17:49:03 +0000, GMAN wrote:
>
>> How are 6 tuners getting you 30 recordable channels at once?
>
>Each tuner receives the full bandwidth of each channel. So, with one
>tuner, you can record up to 5 sub-channels since all five are in the same
>bandwidth. If Tivo had a lick of sense, they would have incorporated this
>into their recorders like the software I use does. Maybe they'll come out
>with a software upgrade for it if you ask, but I doubt it. Like I said, I
>don't use this feature since in my area all the networks have their own
>stations, but in other areas stations broadcast more than one major
>network. Southern OK is a good example where one station broadcast 3
>major networks and another broadcast 2. Two tuners could record all 5 at
>once. There are many stations that broadcast 5 sub-channels, and 2 tuners
>could record all 10 at once. Just one more reason, besides cost, not to
>use a Tivo-HD for OTA.
>
once. (Never mind, i just reread your post) Most stations here in Utah i have
seen broadcast crap or weather info there. There is even one religoius station
here that broadcasts the same signal on the 4 subchannels.
All the major stations here have their own main channel.
Wes Newell
It used to be that way here, but recently, the NBC station started
broadcasting USA sports on a sub-channel and the ABC station started
broadcasting movies on one too. I just found the ABC movie channel by
accident the other day. The local ION station also has qubo on a
subchannel. That would be great for kids while recording an HD movie on
their main channel. Still, the better application for it would be as I
described above. A single ATSC dual tuner card recording 5 networks at
once would keep initial tuner cost down.
JEDIDIAH
>
>
> On Sat, 28 Nov 2009 18:53:06 +0000, GMAN wrote:
>
>> In article <hepbvd$32e$4...@news.eternal-september.org>, Wes Newell
>> <w.ne...@invalid.invalid> wrote:
>>>On Fri, 27 Nov 2009 17:49:03 +0000, GMAN wrote:
>>>
>>>> How are 6 tuners getting you 30 recordable channels at once?
>>>
>>>Each tuner receives the full bandwidth of each channel. So, with one
>>>tuner, you can record up to 5 sub-channels since all five are in the
>>>same bandwidth. If Tivo had a lick of sense, they would have
>>>incorporated this into their recorders like the software I use does.
>>>Maybe they'll come out with a software upgrade for it if you ask, but I
>>>doubt it. Like I said, I don't use this feature since in my area all the
>>>networks have their own stations, but in other areas stations broadcast
>>>more than one major network. Southern OK is a good example where one
>>>station broadcast 3 major networks and another broadcast 2. Two tuners
>>>could record all 5 at once. There are many stations that broadcast 5
>>>sub-channels, and 2 tuners could record all 10 at once. Just one more
>>>reason, besides cost, not to use a Tivo-HD for OTA.
>>>
>> Why would you want to record all of the SD sub channels of a TV station
>> all at once. (Never mind, i just reread your post) Most stations here
>> in Utah i have seen broadcast crap or weather info there. There is even
>> one religoius station here that broadcasts the same signal on the 4
>> subchannels.
>>
>> All the major stations here have their own main channel.
...one of the great things about a PVR is that it goes out and finds
those things that you would never consider looking for yourself due to
your own pre-conceived notions.
>
> It used to be that way here, but recently, the NBC station started
> broadcasting USA sports on a sub-channel and the ABC station started
> broadcasting movies on one too. I just found the ABC movie channel by
> accident the other day. The local ION station also has qubo on a
> subchannel. That would be great for kids while recording an HD movie on
> their main channel. Still, the better application for it would be as I
> described above. A single ATSC dual tuner card recording 5 networks at
> once would keep initial tuner cost down.
>
--
Microsoft: Because the world doesn't have enough peasants. |||
/ | \
Unknown
<w.ne...@invalid.invalid> wrote:
Yep. I don't do OTA but regularly record all 3 HDTV streams in a
single unencrypted TWC channel using a single tuner. Here that means
the national networks in most cases and a few locals tossed in, in
some cases. All HD, none is a sub-channel.
I've noticed that ABC here has a secondary HD channel - also carried
by TWC. So far, nothing of interest - but it's in the guide that I
use, just in case.
The stand alone recorders have a long way to go in this regard - along
with the disk capacity to accommodate it.
Bill Kearney
> with the disk capacity to accommodate it.
It wouldn't take any added disc capacity to store the sub-channels.
Wes Newell
And I'm curious how you came up with this wrong assumption. When you
record a program, only the data for that program is stored to disk.
That's why when you record an SD DTV show, the file size is so much
smaller than the HD program.:-)
JEDIDIAH
>
>
> On Wed, 02 Dec 2009 18:21:04 -0500, Bill Kearney wrote:
>
>>> The stand alone recorders have a long way to go in this regard - along
>>> with the disk capacity to accommodate it.
>>
>> It wouldn't take any added disc capacity to store the sub-channels.
>
> And I'm curious how you came up with this wrong assumption. When you
> record a program, only the data for that program is stored to disk.
> That's why when you record an SD DTV show, the file size is so much
> smaller than the HD program.:-)
...it doesn't sound like you've worked with OTA digital much then.
The amount of bandwidth that broadcasters waste with old reruns is astounding.
--
Nothing today, likely nothing since we tamed fire,
is genuinely new: culture, like science and |||
technology grows by accretion, each new creator / | \
building on the works of those that came before.
Judge Alex Kozinski
US Court of Appeals
9th Circuit
Wes Newell
> On 2009-12-03, Wes Newell <w.ne...@invalid.invalid> wrote:
>>
>>
>> On Wed, 02 Dec 2009 18:21:04 -0500, Bill Kearney wrote:
>>
>>>> The stand alone recorders have a long way to go in this regard -
>>>> along with the disk capacity to accommodate it.
>>>
>>> It wouldn't take any added disc capacity to store the sub-channels.
>>
>> And I'm curious how you came up with this wrong assumption. When you
>> record a program, only the data for that program is stored to disk.
>> That's why when you record an SD DTV show, the file size is so much
>> smaller than the HD program.:-)
>
> ...it doesn't sound like you've worked with OTA digital much then.
>
> The amount of bandwidth that broadcasters waste with old reruns is
> astounding.
Been recording it since 2005. And I know for a fact that all the data is
not stored to HD from a broadcast stream. Only the part for the sub-
channel being recorded. I have no idea what you are talking about.
Perhaps this was intended for Bill.
JEDIDIAH
>
>
> On Thu, 03 Dec 2009 08:14:06 -0600, JEDIDIAH wrote:
>
>> On 2009-12-03, Wes Newell <w.ne...@invalid.invalid> wrote:
>>>
>>>
>>> On Wed, 02 Dec 2009 18:21:04 -0500, Bill Kearney wrote:
>>>
>>>>> The stand alone recorders have a long way to go in this regard -
>>>>> along with the disk capacity to accommodate it.
>>>>
>>>> It wouldn't take any added disc capacity to store the sub-channels.
>>>
>>> And I'm curious how you came up with this wrong assumption. When you
>>> record a program, only the data for that program is stored to disk.
>>> That's why when you record an SD DTV show, the file size is so much
>>> smaller than the HD program.:-)
>>
>> ...it doesn't sound like you've worked with OTA digital much then.
>>
>> The amount of bandwidth that broadcasters waste with old reruns is
>> astounding.
>
> Been recording it since 2005. And I know for a fact that all the data is
> not stored to HD from a broadcast stream. Only the part for the sub-
> channel being recorded. I have no idea what you are talking about.
> Perhaps this was intended for Bill.
Broadcasters aren't terribly efficient about how they encode their SD
signals. This quickly becomes pretty obvious if you deal with this stuff
and have an interest in maximizing recording capacity. It's pretty trivial
to see that the bitrates they send out stuff in is excessive and wasteful.
It doesn't help quality either. There are clearly better quality digital
copies of old SD shows out there on disc. These are usually quite effectively
(and better) encoded at lower bitrates.
--
iTunes is not progressive. It's a throwback. |||
/ | \
Unknown
Perhaps you can expound on this?
I record all streams in a cable channel now (it's an option of the
tuners I'm using). That's 17+ GBph. If I ask for only the stream of
interest, it's typically between 5 and 7 GBph for HDTV and about 2
GBph for SD.
I no longer use an antenna, but I do know that sub-channels require
more than zero bytes per second or hour.
Joe Smith
> On Wed, 02 Dec 2009 18:21:04 -0500, Bill Kearney wrote:
> >> The stand alone recorders have a long way to go in this regard - along
> >> with the disk capacity to accommodate it.
>
> > It wouldn't take any added disc capacity to store the sub-channels.
>
> And I'm curious how you came up with this wrong assumption.
Bill is correct.
A channel with no sub-channels is 18 Mbps.
A channel with two sub-channels can be 9+9 Mbps, 12+6 Mbps, 16+2 Mbps,
etc.
A channel with three sub-channels can be 6+6+6Mbps, 12+3+3 Mbps, etc,
etc.
The amount of disk space consumed is bounded at 18 Mbps * 1B/8b = 2.25
megabytes per second; less if any sub-channels are not being recorded.
-Joe
Joe Smith
> On Wed, 2 Dec 2009 18:21:04 -0500, "Bill Kearney"
>
The total bandwidth for all sub-channels of a single channel cannot
exceed 18 Mbps. That total is distributed among all the sub-
channels. More sub-channels on a single channel means the sub-
channels operate at a lower bitrate.
-Joe
Wes Newell
> On Dec 3, 12:10 am, Wes Newell <w.new...@invalid.invalid> wrote:
>> On Wed, 02 Dec 2009 18:21:04 -0500, Bill Kearney wrote:
>> >> The stand alone recorders have a long way to go in this regard -
>> >> along with the disk capacity to accommodate it.
>>
>> > It wouldn't take any added disc capacity to store the sub-channels.
>>
>> And I'm curious how you came up with this wrong assumption.
>
> Bill is correct.
>
No bill is not correct. How do I know? Well, I can do it with my
recorder, and I can tell you that every show you record takes disk space.
That it's a sub-channel doesn't matter one bit. So if I record 68.1 it
takes a certain amount of space, and if i record 68.3 at the same time,
it takes more space, or less if I record 68.3 alone.
> A channel with no sub-channels is 18 Mbps. A channel with two
> sub-channels can be 9+9 Mbps, 12+6 Mbps, 16+2 Mbps, etc.
> A channel with three sub-channels can be 6+6+6Mbps, 12+3+3 Mbps, etc,
> etc.
> The amount of disk space consumed is bounded at 18 Mbps * 1B/8b = 2.25
> megabytes per second; less if any sub-channels are not being recorded.
>
That's just BS. And it's real easy to prove. Just record X.1 and X.2 at
the same time. Now look at your file system. Now just record X.1 and look
at your file system. Both X.1 files will be approx. the same size. And
the X.2 file will be addition space required to record it. By your way
of thinking all my recordings from the same major channel would be the
same size. They aren't. The HD recording is considerably larger than the
SD recording. If you can read, here's the proof.
[wes@wes2 ~]$ ls -Hs1 /mnt/video/*.mpg
2951236 /mnt/video/1083_20091212233000.mpg
2353532 /mnt/video/1083_20091213020000.mpg
13920168 /mnt/video/1211_20091018140000.mpg
15030720 /mnt/video/1211_20091025160000.mpg
15313100 /mnt/video/1211_20091108140000.mpg
17849832 /mnt/video/1271_20091031143000.mpg
14277344 /mnt/video/1271_20091108150000.mpg
14256156 /mnt/video/1271_20091112190000.mpg
17841048 /mnt/video/1271_20091115143000.mpg
13603948 /mnt/video/1331_20091004030000.mpg
13563624 /mnt/video/1331_20091004130000.mpg
13597632 /mnt/video/1331_20091107123000.mpg
13288420 /mnt/video/1331_20091125190000.mpg
13560484 /mnt/video/1331_20091129190000.mpg
13618948 /mnt/video/1331_20091212130000.mpg
6663596 /mnt/video/1331_20091212200000.mpg
6629960 /mnt/video/1331_20091213030000.mpg
9318020 /mnt/video/1681_20091031200000.mpg
11879532 /mnt/video/1681_20091101193000.mpg
11541108 /mnt/video/1681_20091106173000.mpg
9251780 /mnt/video/1681_20091212140000.mpg
3190080 /mnt/video/1683_20091119200000.mpg
[wes@wes2 ~]$
The actual channel number is the first 4 digits. 1083 is channel 8.3. The
rest is date and time recording started. All of these are movies I
recorded OTA. None are less than 2 hours. a few are 2.5 hours, like the
ones that's 17GB (all are in K blocks). Note the difference in file
sizes. And all these stations broadcast in 1080i. Enough said.
Wes Newell
True, but you only record the bits you need. For a station with 5 equal
sub-channels, you only record the portion that you select. So if you only
record 1 of them the space required is 1/5 of the stream. Record 2, 2/5
(in 2 separate files), etc.
Joe Smith
> On Sat, 12 Dec 2009 23:50:45 -0800, Joe Smith wrote:
>
> > A channel with no sub-channels is 18 Mbps. A channel with two
> > sub-channels can be 9+9 Mbps, 12+6 Mbps, 16+2 Mbps, etc.
> > A channel with three sub-channels can be 6+6+6Mbps, 12+3+3 Mbps, etc,
> > etc.
> > The amount of disk space consumed is bounded at 18 Mbps * 1B/8b = 2.25
> > megabytes per second; less if any sub-channels are not being recorded.
The fact remains that the total amount of bits per second transmitted
over the air on a single RF channel is fixed by the ATSC
specifications. Whenever more than one sub-channel is being used,
each one gets a lower bitrate than what a single sub-channel would
get. That part is undeniable.
> That's just BS. And it's real easy to prove. Just record X.1 and X.2 at
> the same time. Now look at your file system. Now just record X.1 and look
> at your file system. Both X.1 files will be approx. the same size.
No, that is not what I'm talking about at all.
1) Record KQED channel 9.1 for an hour during primetime when that San
Francisco station station has shut down most of its other sub-channels
(so that it can devote the maximum bit-rate to its 1080i programming).
2) Record KQED channels 9.1, 9.2 and 9.3 for an hour during the
afternoon. Notice that the size of the file for sub-channel 9.1 is
much smaller than the one recording during primetime.
The sum total for file sizes recorded during the afternoon will be
approximately the same size as the one primetime recording.
In regards for disk capacity:
A) Calculate the amount of disk space that would be required to hold N
hours of recordings, assuming that each station is using all the
bandwidth on a single 1080i broadcast.
B) Record those N hours of programming (one sub-channel only per
tuner).
C) Notice that the actual amount of disk space used is less than
calculated in "A". This is due to all the sub-channels that are not
being recorded by a single-subchannel-only tuner.
D) Upgrade hardware and software to record all the sub-channels of a
single tuned channel.
E) Record those N hours of programming, recording all sub-channels of
each tuner.
F) Notice that the actual amount of disk space used is more than "C",
and less than or equal to "A".
Bill Kearney wrote:
>> The stand alone recorders have a long way to go in this regard - along
>> with the disk capacity to accommodate it.
>
>It wouldn't take any added disc capacity to store the sub-channels.
Bill is correct. It would not take any more disk capacity to store
all the sub-channels assuming that the recorder was designed for the
best-case scenario, where all of the single-subchannel-only recordings
came in at the maximum bit-rate.
On the other hand, if the recorder was designed for the average
scenario, where single-subchannel-only recordings came in with only a
subset of the maximum bit-rate, then additional disk capacity would be
required.
Now, does that clear things up?
-Joe
Wes Newell
> On Dec 13 2009, 2:24 am, Wes Newell <w.new...@invalid.invalid> wrote:
>> On Sat, 12 Dec 2009 23:50:45 -0800, Joe Smith wrote:
>>
>> > A channel with no sub-channels is 18 Mbps. A channel with two
>> > sub-channels can be 9+9 Mbps, 12+6 Mbps, 16+2 Mbps, etc. A channel
>> > with three sub-channels can be 6+6+6Mbps, 12+3+3 Mbps, etc, etc.
>> > The amount of disk space consumed is bounded at 18 Mbps * 1B/8b =
>> > 2.25 megabytes per second; less if any sub-channels are not being
>> > recorded.
>
> The fact remains that the total amount of bits per second transmitted
> over the air on a single RF channel is fixed by the ATSC specifications.
> Whenever more than one sub-channel is being used, each one gets a lower
> bitrate than what a single sub-channel would get. That part is
> undeniable.
>
True, and has absolutely nothing to do with the subject matter. The
amount of disk space a recording takes.
>> That's just BS. And it's real easy to prove. Just record X.1 and X.2
>> at the same time. Now look at your file system. Now just record X.1 and
>> look at your file system. Both X.1 files will be approx. the same size.
>
> No, that is not what I'm talking about at all.
>
Well, that was what the original poster was talking about.
> 1) Record KQED channel 9.1 for an hour during primetime when that San
> Francisco station station has shut down most of its other sub-channels
> (so that it can devote the maximum bit-rate to its 1080i programming).
> 2) Record KQED channels 9.1, 9.2 and 9.3 for an hour during the
> afternoon. Notice that the size of the file for sub-channel 9.1 is much
> smaller than the one recording during primetime. The sum total for file
> sizes recorded during the afternoon will be approximately the same size
> as the one primetime recording.
>
I don't know of any stations that shut down their subchannels as you
describe, but if they did what you said, what you said is correct.
> In regards for disk capacity:
>
> A) Calculate the amount of disk space that would be required to hold N
> hours of recordings, assuming that each station is using all the
> bandwidth on a single 1080i broadcast. B) Record those N hours of
> programming (one sub-channel only per tuner).
Ok, That's approximately 7GB per hour for a 1080i broadcast from a
station using its full bandwidth for the 1 channel.
> C) Notice that the actual amount of disk space used is less than
> calculated in "A". This is due to all the sub-channels that are not
> being recorded by a single-subchannel-only tuner.
If the station had more than one channel, then the 7GB would be divided
between the recordings. BTW, there's no such thing as a single subchannel
tuner. Any ATSC tuner is capable of recording any and all subchannels
broadcast over the frequency. That Tivo doesn't allow this is just a Tivo
thing. The tuner is receiving the entire bandwidth.
> D) Upgrade hardware
> and software to record all the sub-channels of a single tuned channel.
Again, you wouldn't have to upgrade the tuner. For a Tivo, you'd
certainly have to upgrade the software, and probably the controlling
hardware (CPU/ram/etc.)
> E) Record those N hours of programming, recording all sub-channels of
> each tuner.
> F) Notice that the actual amount of disk space used is more than "C",
> and less than or equal to "A".
>
Well, no kidding. That's what I was saying in the first place. But it has
nothing to do with the tuner. You're making something so simple hard to
follow.
> Bill Kearney wrote:
>>> The stand alone recorders have a long way to go in this regard - along
>>> with the disk capacity to accommodate it.
>>
>>It wouldn't take any added disc capacity to store the sub-channels.
>
> Bill is correct. It would not take any more disk capacity to store all
> the sub-channels assuming that the recorder was designed for the
> best-case scenario, where all of the single-subchannel-only recordings
> came in at the maximum bit-rate.
>
No, Bill is not correct, and neither or you. You just proved that
yourself. A station with 2 subchannels (.1 and .2) equally split would
only take 3.5GB to record one of them, and 7GB to record both of them.
Using 1 or 2 tuners doesn't matter.
Bill was saying it wouldn't take any more disk space to record the extra
subchannels, which is clearly stupid. I expect that from Bill though.
You're basically saying that if you record 1 channel of full bandwidth
and another split 5 ways, but record all 5 subchannels that the space
required would be the same, and that's correct. IOW's you're saying the
same thing I did only in a dumb way.
> On the other hand, if the recorder was designed for the average
> scenario, where single-subchannel-only recordings came in with only a
> subset of the maximum bit-rate, then additional disk capacity would be
> required.
>
> Now, does that clear things up?
Not at all. You've only muddied the waters. I'll simplify it.
If a channel has more than one subchannel, each one you record will take
addition disk space. The tuners used for this has no bearing on the
matter. The space will be the same using a single tuner for all
subchannels (something Tivo users can't do), or a separate tuner for each
subchannel. Now, was that too hard?:-)
Gordon Burditt
Are you sure? Or is it *up to* 18 Mbps? How do you transmit a
single *SD* channel at 18Mbps?
Gordon Burditt
>exceed 18 Mbps.
Can it be *LESS* than 18 Mbps?
>That total is distributed among all the sub-
>channels. More sub-channels on a single channel means the sub-
>channels operate at a lower bitrate.
One SD channel: 6 Mbps.
Two SD channels: 6 Mbps + 6 Mbps.
Three SD channels: 6 Mbps + 6 Mbps + 6 Mbps.
Note that the bit rate on the first subchannel did not go down when
the other two were added.