Raspberry Pi as a DVR? / TV recorder?


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by bobdotexe » Thu Apr 12, 2012 5:57 pm
Dose any one know if any Digital tv tuners or capture cards will work with the raspberry pi? I was thinking about using it to record, or  stream(locally) live TV.
I currently have one of thous usb easycap cards, But I was thinking about getting a tv tuner.


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by nullstring » Thu Apr 12, 2012 6:17 pm
I've heard multiple reports that TV tuners will work with various routers running OpenWRT. If they can handle it, I don't see why the RPI couldn't.

The issue comes in when you realize that all OTA broadcasts in the USA are encoded in mpeg2, which the RPI doesn't support. This puts a damper in our plan. =(

[I was originally going to do this. RPI -> way way cheap DVR]

I don't know much about the broadcasts in other parts of the world, but I hear many of them are also mpeg2
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by patrikg » Thu Apr 12, 2012 7:13 pm
Maybe this company ??

http://sundtek.com/shop/home/

They support linux boxes like dreambox.

/Patrik
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by Jim Manley » Thu Apr 12, 2012 7:15 pm
AIUI, it"s a matter of whether the MPEG2 content is protected, right? Or, are there no codecs (yet?) for MPEG (of any flavor) on the Pi?
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by nullstring » Thu Apr 12, 2012 8:08 pm
Jim Manley said:


AIUI, it"s a matter of whether the MPEG2 content is protected, right? Or, are there no codecs (yet?) for MPEG (of any flavor) on the Pi?


It has nothing to do with protection.

There is other threads/blog post that outline this better than I can in a few words.. but..

RPI foundation has only acquired licenses for mpeg4 (XVID) and h.264 and therefore the RPI can't (hardware) decode any other content.

This would include HD ATSC broadcasts which are in mpeg2.

To be clear, working hardware codecs exist for the RPI to decode mpeg2, VC-1, etc.

It's not a matter of software or hardware. It's a matter of paying licensing fees to MPEG and the RPI foundation to allow consumer use of mpeg2 technoligy. (Which are apparently not cheap. If you find the previous thread/blog post it'll have more details)
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by poing » Thu Apr 12, 2012 8:16 pm
Correct me if I'm wrong but I always understood that sticks like the SundTek just pass on the data and any decoding takes place at the viewing end (TV, computer)? They also record just the stream AFAIK.

So I think you could use the stick on a RPi where the antenna enters the house and then move the data over the LAN to where you want to watch. Recording takes place at the RPi on a HD.

See here with a post from SundTek: http://www.raspberrypi.org/for.....g-software
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by nullstring » Thu Apr 12, 2012 8:34 pm
poing said:


Correct me if I'm wrong but I always understood that sticks like the SundTek just pass on the data and any decoding takes place at the viewing end (TV, computer)? They also record just the stream AFAIK.

So I think you could use the stick on a RPi where the antenna enters the house and then move the data over the LAN to where you want to watch. Recording takes place at the RPi on a HD.

See here with a post from SundTek: http://www.raspberrypi.org/for.....g-software


Thats is completely correct.

The decoding happens on the computer (or other device.) Not the TV.

But what that means is you couldn;t hook the RPI to the TV and expect to be able to view any of your recorded TV show... so you'd need another device just for that.
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by Jim Manley » Thu Apr 12, 2012 9:03 pm
So, who pays the MPEG license fees for freeware like MythTV on Linux - the receiver/tuner card/stick manufacturers? MP3 is an MPEG layer, but, a lot of people aren"t paying any license fees for that, AFAIK. I recall that DIRECTiVo recorded encrypted MPEG2 directly off the satellite, then hardware decrypted/decoded the recordings during playback, since they had a business relationship (and both paid MPEG fees, I guess). Does broadcast ATSC encode MPEG and, if so, where are the fees paid there, by the broadcasters? Do you only pay fees if you"re selling something that uses it?
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by mole125 » Thu Apr 12, 2012 9:12 pm
The end users are legally required to pay the appropriate fees if the manufacture hasn't.

So far the license holders haven't been bothered to sue individual users for patent infringement.

Generally, for broadcast TV systems, firstly, the mpeg license fees will have to be paid by the encoder manufacturer which is used to encode the tv into mpeg streams. License fees will also need to be paid by the set top box manufacturer in order to pay to use the algorithms to decode the transport streams.
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by poing » Thu Apr 12, 2012 9:16 pm
Additionally, I have two old CRT TVs (with analog cable) and was thinking of upgrading to digital DVB-T. Most TVs nowadays have a built-in DVB-T tuner and a CAM (Conditional Access Module) for a smart card that comes with the subscription.

As DVB-T is MPEG2 also I guess the TV itself must be able to decode the MPEG2 stream. What I don't know is if it can do that also from it's Ethernet port (assuming a model that has one of course).

The ideal situation is of course where the computer attached to the TV stick also has a CAM module with the smart card so everyone in the house can watch subscription channels with the one card. But is this possible with a RPi without MPEG2 decoding? (I guess this borders on illegality although locally I can use up to three smart cards with the basic subscription.)
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by poing » Thu Apr 12, 2012 9:18 pm
mole125 said:


Generally, for broadcast TV systems, firstly, the mpeg license fees will have to be paid by the encoder manufacturer which is used to encode the tv into mpeg streams. License fees will also need to be paid by the set top box manufacturer in order to pay to use the algorithms to decode the transport streams.


This was probably invented by one of those blokes that learned coding on a BBC Micro ;-)

I want to get smart too, where's my RPi?
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by Jim Manley » Thu Apr 12, 2012 9:25 pm

Does broadcast ATSC encode MPEG and, if so, where are the fees paid there, by the broadcasters?


Ah, I see that MPEG LA, LLC, also owns the patent(s) for ATSC. That explains why I saw so many job openings for video processing software engineers in/around Denver, where MPEG LA, LLC, is located (along with Dish, et al).
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by nullstring » Thu Apr 12, 2012 9:37 pm
Jim Manley said:


So, who pays the MPEG license fees for freeware like MythTV on Linux - the receiver/tuner card/stick manufacturers? MP3 is an MPEG layer, but, a lot of people aren"t paying any license fees for that, AFAIK. I recall that DIRECTiVo recorded encrypted MPEG2 directly off the satellite, then hardware decrypted/decoded the recordings during playback, since they had a business relationship (and both paid MPEG fees, I guess). Does broadcast ATSC encode MPEG and, if so, where are the fees paid there, by the broadcasters? Do you only pay fees if you"re selling something that uses it?



Using "freeware" mpeg decoders without paying any fees is arguably illegal. Many people don't pay these fees, but they are suppose to. However, it's impractical (and possibly even unnecessary) to track down all these users and force them to pay fees.

[Disclaimer: IDK if I had the details as to where the illegality actually is. (use, distribution, etc etc. not sure)

However, hardware vendors and paid software vendors can't get around the fees so easily.

So, yes, DirectTV (or one of it's vendors) pays MPEG fees.

Same thing with the ATSC broadcasters.

Same thing with any ipod, cell phone, bluray player, etc, etc.
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by Jim Manley » Thu Apr 12, 2012 9:40 pm
mole125 said:

The end users are legally required to pay the appropriate fees if the manufacture hasn"t.

So far the license holders haven"t been bothered to sue individual users for patent infringement.


Obviously, these guys can"t afford the RIAA"s and MPAA"s "quality" of lawyers :) Although, apparently, the RIAA has recently given up suing individuals who have no money (huh, I guess there _is_ a difference between business school and law school) and instead are going to focus on "education" of infringing individuals - shades of "1984"! Does anyone else feel a sudden chilly draft? :(
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by poing » Thu Apr 12, 2012 9:43 pm
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by nullstring » Thu Apr 12, 2012 10:11 pm
Jim Manley said:


mole125 said:


The end users are legally required to pay the appropriate fees if the manufacture hasn"t.

So far the license holders haven"t been bothered to sue individual users for patent infringement.


Obviously, these guys can"t afford the RIAA"s and MPAA"s "quality" of lawyers :) Although, apparently, the RIAA has recently given up suing individuals who have no money (huh, I guess there _is_ a difference between business school and law school) and instead are going to focus on "education" of infringing individuals - shades of "1984"! Does anyone else feel a sudden chilly draft? :(


Actually, this falls under the photoshop argument.

How can photoshop be so successful but also so expensive?

It's because they want students, etc. to pirate it. These people pirate it, get good at it, and then when they get hired... the employer has no choice but to pay for it... because it's cheaper/better to pay for a good product that they employee already knows how to use.

The loss of revenue of people who can't afford to buy it anyway is well worth it, since they become the standard.

The same thing works with mpeg. although illegal in some way, non-commercial users use mpeg for free. These user can't afford/would refuse to pay the lisceneses anyway. In return for letting them use it for free, it because the widespread standard of the internet.

What would happen if mpeg started to enforce patent laws? Alternative technologies could be developed to replace it. They would no longer be the standard upon encoding technologies and could possibly lose space in other market shares because of this.

My wording here isn't very good, but hopefully you get the point.
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by drgeoff » Thu Apr 12, 2012 10:25 pm
Jim Manley said:



Does broadcast ATSC encode MPEG and, if so, where are the fees paid there, by the broadcasters?


Ah, I see that MPEG LA, LLC, also owns the patent(s) for ATSC. That explains why I saw so many job openings for video processing software engineers in/around Denver, where MPEG LA, LLC, is located (along with Dish, et al).



MPEG LA does not own the patents.  They act as agents for the patent owners.  It is not a requirement that the patent owners use the services of MPEG LA but most do so because it makes things simpler for both licensors and licensees.
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by Jim Manley » Fri Apr 13, 2012 12:28 am
drgeoff said:


MPEG LA does not own the patents.  They act as agents for the patent owners.  It is not a requirement that the patent owners use the services of MPEG LA but most do so because it makes things simpler for both licensors and licensees.


Yeah, I got distracted during editing and wrote "owned" instead of "represented the owners". So, sue me, and good luck collecting even if you wasted the effort!
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by Cab121 » Thu Jan 17, 2013 1:34 am
Since MPEG-2 and VC-1 are now available. Is this a green light for the above plan?
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by ghans » Thu Jan 17, 2013 8:54 am
Nope , those devices need isynchronous USB transfers ,
and these need a whole load of fixing.
Nobody i know got capture cards to work.

ghans
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by Fireb4ll455 » Wed Mar 13, 2013 1:18 pm
What about using a networked tuner like the SiliconDust HDHomerun, http://www.silicondust.com/ ?

My follow-up question is if a networked tuner IS used, where will the TV shows be stored? Will an USB2 hard drive attached to the Rpi be sufficient?
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by ghans » Wed Mar 13, 2013 10:34 pm
I have heard reports of problems with the HDHomeRun ,
but theoretically it should work.

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by observing » Fri Mar 29, 2013 5:48 pm
This announcement from silicondust might be of interest to some of you:
http://www.engadget.com/2013/03/29/hdho ... -out-of-b/
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by Jim Manley » Sat Mar 30, 2013 12:24 am
The Pi hardware is never going to be able to handle the required bandwidth (over 25 Mbits/sec for starters). As we say in Joisey, "Fuhgeddaboudid!"
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by SeanHeron » Mon Apr 01, 2013 8:52 pm
Ok - I have a similar / more or less the same question as the OP. Unfortunately, reading this thread I still only have a vague idea of whether it's possible or not. I got that there are the following issues:
* A TV/Video tuner is required - USB tuner would be the first to spring to mind (I've thought that as well), however, these apparently don't work with the Pi (due to issues with implementation of USB protocol ??)
* Alternative - hook up a Video tuner via Network. However, here there was the statement that bandwidth is a problem; I don't quite understand in what manner though (not that I'm clued - I don't even have the device yet...): 24 MByte per second - for a 100 Mbit Network "card" that - ah wait. Of course, 100 Mbit is ~ 16 Mbyte max. Ok, and I'll assume that the Pi doesn't come with a Gigabit Ethernet... Question in that case - is the 24 Mbyte referring to HD, or just in general - ie if I don't need HD, might it be possible after all?
I think that's mostly it, thanks for any answers!

(P.S. pardon my english, I've been living "abroad" for the longest part of my life...)
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