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mikesm
01-21-2008, 11:38 PM
Hi. I am a newbie to the tivo hacking community, but have a lot fo experience building high end DVR systems, first with MCE and now with Sage. Given the functionality of s3tots, I was wondering if someone could comment on how hard it would be to turn a tivo S3 into a cablecard network encoder?

What I mean here is that a daemon would run on the S3, listen for commands on a socket from a PVR system like MythTV or SageTV, receive a command to tune to a specific channel, and then stream the MPEG2 data over it's ethernet port to the MythTV or SageTV server.

This would have several advantages:

1) You get all the benefits of a distributed DVR system like SageTv or MythTV, including automatic commercial skip, ease of burning to DVD, distributed client support and cheap extenders (at least with Sage), consolidated interface to ripped media, as well as recorded TV, etc...

2) No need to expand disk space on the Tivo, since the programs wouldn't need to be stored there anymore.

3) No tivo subscription would be needed, since the EPG and such are provided through the PVR system. All the tivo does in this scenario is manage the mapping of channels to specific carriers and subprograms, the cablecard security, and streaming the resulting content over the LAN.

Is there anything about the tivo system that would prevent this scenario from being actualized?

Sage supports network encoders for things the the R5000-HD modification to cable and DBS boxes, the older non- BDA HDHomerun, etc.... And this would be I think pretty easy to integrate into MythTV as well.

Comments?

bcc
01-22-2008, 07:46 PM
I don't see a technical roadblock to such a thing, so long as you aren't making real-time a requirement.

If you're thinking of packaging tivo hacks into a for-sale sagetv product, there may be licensing/copyright issues.

mikesm
01-22-2008, 08:41 PM
I don't see a technical roadblock to such a thing, so long as you aren't making real-time a requirement.

If you're thinking of packaging tivo hacks into a for-sale sagetv product, there may be licensing/copyright issues.

This wouldn't be a forsale product of course, but rather code that users with a modified box could run. There are also a lot of mythtv users out there looking for hd tuner solutions.

What do you mean by realtime? I wouldn't want the tivo writing to disk first, but just streaming the mpeg2 stream over the ethernet. A few secs of tuning/buffering delay isn't a problem, but are you saying it would have to be store and forward? If so, why?

Jamie
01-22-2008, 09:29 PM
I haven't verified this, but it wouldn't surprise me if "cablecard security" won't work without a tivo subscription. If I were TiVo, I'd be inclined to disable the cablecards when in doorstop mode.

Streaming to the network without going to disk first is not supported by the tivo software. You might be able to do it, but you'd either have to intercept the stream before it was written to disk, or reverse engineer enough of the undocumented device kernel interfaces to replace tivoapp with your own code. The first is probably easier than the second. I seem to remember a thread on the now defunct alt.org forums where someone did something like this. It would certainly be easier to "store and forward".

bcc
01-22-2008, 09:29 PM
This wouldn't be a forsale product of course, but rather code that users with a modified box could run. There are also a lot of mythtv users out there looking for hd tuner solutions.Probably not a problem then.
What do you mean by realtime? By realtime I mean streaming the content out the ethernet and playing/processing it elsewhere while the recording is actively being made. You could easily "catch up" to the end of the recording in such cases. The state of the tivo chunks (such as the # of valid chunks per segment) are not set as expected until the segment is written completely.
There may also not be enough CPU resources to record 2 HD streams simultaneously, extract 1 HD stream at a sustained 19Mbps and also play back something else at the same time.
I wouldn't want the tivo writing to disk first, but just streaming the mpeg2 stream over the ethernet.Well tivo always writes to disk, even when you're watching "live" tv.
are you saying it would have to be store and forward? If so, why?Think of it as a queue that you're better off never fully emptying if that makes you feel better :)

bcc
01-22-2008, 09:34 PM
I haven't verified this, but it wouldn't surprise me if "cablecard security" won't work without a tivo subscription. If I were TiVo, I'd be inclined to disable the cablecards when in doorstop mode.Thanks, I hadn't noticed that lack of Tivo subscription was one of the requirements.

newbie
01-23-2008, 02:27 PM
I haven't verified this, but it wouldn't surprise me if "cablecard security" won't work without a tivo subscription. If I were TiVo, I'd be inclined to disable the cablecards when in doorstop mode.




You can use the cablecard in a Tivo HD to tune to and watch a subscribed channel even if you don't have a tivo subscription.

Personal experience, as well as being told that from tivo phone representatives.

This sidesteps the question of such a tivo not being able to record anything.

Jamie
01-23-2008, 02:47 PM
This sidesteps the question of such a tivo not being able to record anything.It's still getting recording into the live buffer, isn't it? So, at least in theory, you could intercept the data is it is written to the live buffer by intercepting the right kernel calls.

mikesm
01-23-2008, 10:22 PM
You can use the cablecard in a Tivo HD to tune to and watch a subscribed channel even if you don't have a tivo subscription.

Personal experience, as well as being told that from tivo phone representatives.

This sidesteps the question of such a tivo not being able to record anything.

That's also my understanding of how the cablecard integration works. Its separate from the service.

In my proposed model, the tivo would get a command to tune to a channel and then effectively do a manual record.

If it has to write to a file, could it write to a filesystem that was mounted over the network? That's how some network encoders work today - they have the ability to mount a UNC filepath, and the record command passes the filename to be used for the writing...

SpoonsJTD
01-24-2008, 11:30 AM
I asked a similar question a while back in a different thread and got similar answers. I think this would be neat to have for the DirecTivo's as well. I'd love to stick my DTV boxes in a rack in the basement and use them simply as tuners. I've been waiting (and imagine i'll continue waiting for a while) for the DTV tuner card that was discussed two CES's ago.