MRV - copy rather than stream?

[nsayer]

Maybe it's too late, but I think a lot of the difficulty that DirecTV is having in getting MRV to work stems from the fact that they stream the shows rather than copy them.

TiVo has had MRV for a while now, and the mechanism they use is copying encrypted files over the network and then playing them locally from whatever device they've been copied to. If they were to go this route, then the functionality would be almost exactly the same as their existing on-demand functionality. The only difference would be where the stuff comes from.

Is it DirecTV's assertion that that mechanism is somehow illegal, immoral or fattening and that network streaming is the only way they can do MRV?

 

[cfb]

I think the recorded data stream is encrypted on the "owning" HR with a key that is unique to the receiver, perhaps something on the access card.

So the receiving HR would be unable to decrypt it, and I'd presume that passing the key from one HR to another is just past the line where directv is comfortable with exposing content.

This is also what prevents you from taking an esata drive off of one HR and plugging it into another and playing the content.

Theres also no mpeg2/4 encoder in the box (at least none i'm aware of), so they cant decrypt and recompress/encode the stream.

Unfortunately, I think dtv's method of streaming unencoded pure video is going to be a nice check box marketing item, but I dont think its going to work on most peoples current home networks unless the customer already has a bunch of wires run, has an 11n wireless network and some wireless n bridges kicking around, or is willing to invest $100-200 in new cabling or gear.

I'm expecting their CSRs to get thousands of calls from people having trouble with MRV and directv2pc playback when the products are released. I also wouldnt be surprised to see MRV yanked when the current CE goes NR, or at least require a hidden keyword search to enable it.

 

[JosephB]

I think the recorded data stream is encrypted on the "owning" HR with a key that is unique to the receiver, perhaps something on the access card.

So the receiving HR would be unable to decrypt it, and I'd presume that passing the key from one HR to another is just past the line where directv is comfortable with exposing content.

This is also what prevents you from taking an esata drive off of one HR and plugging it into another and playing the content.

Theres also no mpeg2/4 encoder in the box (at least none i'm aware of), so they cant decrypt and recompress/encode the stream.

Unfortunately, I think dtv's method of streaming unencoded pure video is going to be a nice check box marketing item, but I dont think its going to work on most peoples current home networks unless the customer already has a bunch of wires run, has an 11n wireless network and some wireless n bridges kicking around, or is willing to invest $100-200 in new cabling or gear.

I'm expecting their CSRs to get thousands of calls from people having trouble with MRV and directv2pc playback when the products are released. I also wouldnt be surprised to see MRV yanked when the current CE goes NR, or at least require a hidden keyword search to enable it.

The video isn't stored "unencoded" on the hard drive at any time. The DVRs work by recording bit for bit what comes down from the satellite. They have hardware decoders onboard that decrypt/decode the video as it's viewed, not as it's recorded. When it's streamed over to another DVR, it's streamed encoded. Raw HD video takes gigabytes per minute and an hour would fill the hard drive of an HR23. Not to mention that no transport method in anyone's home would be able to carry it.

From a usability standpoint, streaming is better because people can just look at the master list and click play, no waiting for it to copy over, no worrying about having it on many different DVRs. I think what DirecTV needs to do is a compromise between the two. Buffer it and just wait a second or two before starting to play it, longer than they do now. A buffering time at the beginning is better IMO than jitters throughout the recording.

 

[cfb]

I agree with most of what you said, and I think my post reflects that...in the 5th paragraph of my post I should have said 'unencrypted' instead of 'unencoded'. Typing when you have a 4 year old whacking you with a nerf sword does have its drawbacks.

Where we differ is where I think the 'decryption' of the recorded sat stream takes place for MRV, and unless I'm badly mistaken that happens at the source/recording dvr. The stream from that dvr to the receiver H2x/HR2x is then encrypted with DTCP over the wire and played back unencrypted at the local receiver.

Buffering might help, although if the underlying network is unable to keep up the buffering wont be a major benefit unless directv incorporates the "whoops, out of buffer...please wait" and pauses the playback while it refills the buffer. Pretty much what you get when you try to watch internet HD content on a PC using an internet connection thats too slow.

Plus you'd shoot the buffer to hell the first time you hit 30-skip/30-slip 5-6 times.

Transferring the show works on any network, with the only problems being if there is a shortage of disk space on the receiving unit. The only hole in that setup is that (if I'm right) the show would be stored in an unencrypted format on the receivers hard drive and that seems to be an automatic "NO!" for directv.

 

[rad]

IMHO DirecTV won't do the copy just because it doesn't fit their plans of having a 'media server' type box that feeds the other STB's, like AT&T does with U-verse (which they partner with). I really don't see the network component being the problem, at least for the MRV problems I see, since they happen on a 100Mbps direct connection between to STB's and I don't see issues when using my full network config playing content to DirecTV2PC client for same programs. Althought since DirecTV purchased the Replay patents, and they had a working MRV years ago that's much more full function then what we have now, I don't know why we're seeing such slow progress getting some of the 'day one' issues fixed by now.

 

[JosephB]

I agree with most of what you said, and I think my post reflects that...in the 5th paragraph of my post I should have said 'unencrypted' instead of 'unencoded'. Typing when you have a 4 year old whacking you with a nerf sword does have its drawbacks.

Where we differ is where I think the 'decryption' of the recorded sat stream takes place for MRV, and unless I'm badly mistaken that happens at the source/recording dvr. The stream from that dvr to the receiver H2x/HR2x is then encrypted with DTCP over the wire and played back unencrypted at the local receiver.

Buffering might help, although if the underlying network is unable to keep up the buffering wont be a major benefit unless directv incorporates the "whoops, out of buffer...please wait" and pauses the playback while it refills the buffer. Pretty much what you get when you try to watch internet HD content on a PC using an internet connection thats too slow.

Plus you'd shoot the buffer to hell the first time you hit 30-skip/30-slip 5-6 times.

Transferring the show works on any network, with the only problems being if there is a shortage of disk space on the receiving unit. The only hole in that setup is that (if I'm right) the show would be stored in an unencrypted format on the receivers hard drive and that seems to be an automatic "NO!" for directv.

It's never stored unencrypted anywhere, even on the original DVR. The DVRs record the bits exactly as they are broadcast. When you play it back, the bitstream is passed through the CAM and the decoders just as if it were a live broadcast. This is why integrated DVRs are so cheap compared to Tivo or cable DVRs with encoders, encryption modules, etc. The only difference I assume is that the keys are probably stored with the files so that if they change and you want to watch it later, the box knows how to decode it.

Decryption and decoding are not very hard on the boxes, and they aren't the bottleneck because they have dedicated hardware to do it. The access card handles decryption, so none of that is done at the CPU, and there is an MPEG2/MPEG4 hardware decoder on board, so that doesn't touch the CPU either.

 

[cfb]

I completely understand and agree with everything you said. I'm quite familiar with all of the hardware in the HR2x. The software is occasionaly a bit of a mystery, however.

The issue is that if the sending box is doing the decoding (and I think it is) and storing the content elsewhere after transmission isnt an option (and I dont think it is for directv) then streaming it in real time and playing that stream in real time with the anticipation of very little in the way of error conditions or sudden drops in throughput is the only option.

That puts a heavy burden on the network. My experience has been that a fairly solid 200Mb/s powerline, 802.11n wireless or wired are the only reliable network transports that can do this. Even then the wireless/powerline options might be iffy for a good size number of people.

I know some people under what must be very good circumstances have gotten MRV to run on the 85Mb/s powerline and 11g wireless networks, but I wouldnt expect that to be the norm.

I think the problem with this method upon release to the masses is that while all of us here are enthusiasts willing to spend some money on networking (or already have a pretty good network), joe sixpack maybe has an 11g router for his laptop or might only have a desktop computer plugged into a hardwired router. Perhaps joe picked up some of directv's 85Mb/s powerline adapters to get VOD to his DVR if he was really feeling techwhizzy.

I'd anticipate the percentage of users with wired networks to all their receivers or 11n/200Mb/s powerline AV networks to be in the single digit percentage range.

 

[JosephB]

I'm willing to bet when this gets released to the general public SWM is going to be the preferred method of transport, and then they can just burn a SWM channel to send it reliably without any issue.

 

[rad]

I'm willing to bet when this gets released to the general public SWM is going to be the preferred method of transport, and then they can just burn a SWM channel to send it reliably without any issue.

But then they've locked out all the subs that don't have a SWM setup, which is the majority. As I mentioned earlier, IMHO, the network (assuming a 100Mbps wired) can handle MRV without any problems. Through one 100Mbps uplink via a switch I've had two H2X MRV sessions plus a DirecTV2PC session to HR2X's on the other side of the uplink and saw no problems on the DirecTV2PC playback and the usual glitches on the H2X's. I've also seen the usual glitches with a HR23 and H21 directly connected to each other, no other devices/traffic on the connection. That leads me to there's still something that DirecTV needs to fix in the hardware/software on the HR2X or H2X's.

Not saying that there won't be a SWM solution, it would make sense that they did have one to make MRV installs easier.

 

[cfb]

Directv is a partner in MOCA, so thats a plausible option to do networking. Only problem is that existing receivers would need a moca bridge for each unit. Pricing on those is going to be in the $75-100 range, but the throughput will be good and more predictable than powerline or wireless. You might also need a different multiswitch or SWM for it to work.

MoCA :: Multimedia over Coax Alliance

 

[JosephB]

DirecTV has already announced that MRV will be working over SWM and it's speculated (and highly likely) that no additional equipment will be required.

 

[vurbano]

Is it DirecTV's assertion that that mechanism is somehow illegal, immoral or fattening and that network streaming is the only way they can do MRV?

Yes. You will never see it offered with D*. It hasnt been possible since the HR10-250 HD tivo and only because it was a tivo kernel and you had to hack it or replace the kernel and then break the encryption. IF it ever happens with the HR20 you will see it over at dealdatabase.com. To appease people they allow you to play musical chairs with external hard drives with no way of actually organizing your recordings. Stupidity. They wont even put out software to lock down recordings on a server that you could copy too. Its just really asinine.