Can DirecTiVo be made to tune & record HDTV bitstreams?

[HDTiVo]

There must be some sort of "serviceID" associated
with HDTV channels so that a DirecTiVo (and other
non-HD receivers) don't show them in the guide
or tune to them.

Does anyone know how to change some code on
a DirecTiVo so that you could select chan 199?

Then maybe we could record the bitstream to HD
and use TiVoNet to pull it off and play it back
on some other device with an HD ATSC/MPEG2
decoder system.

Has anyone tried this yet?

[BubbaJ]

AFAIK no one's tried this yet.. do a search there's some old posts about this topic

[AlphaWolf]

Actualy the thing on that...I think around 4 months or so somebody figured out how to make it actualy record the hdtv feed, but since video extraction wasn't quite possible at the time, it wasn't actualy verified as being possible. The mpeg decoder would puke when it tried to play back the data because it didn't like the video format or something. Now that video extraction is nearly in the state of perfection, who knows? shall we revive this old subject?

[KRavEN]

Once the current extraction effort is complete, I'm going to direct my full attention to getting this ability. We allready know how to manually tune to a channel and there a scripts to manually record, I think we just have to put 2 and 2 together. It would also be nice to populate the guide so you could schedule the recordings too, maybe Juppers can lend a hand with his expertise in that area.

[BubbaJ]

~20Mbit/sec
/8 = 2.5MByte/sec
*60 = 150MByte/min
*60 = 9000MByte/Hr
*2 = 18000MByte
so ~18GB for a 2 hour movie, presuming that they're using the full available bandwidth. My miniDV Camcorder uses more than that, but for lower resolution uncompressed footage.

[HDTiVo]

~16gb for 2 hours is about right for
a 2 hour movie in HDTV.

The ATSC standard specifies 19.3Mbit/sec
for broadcast (and some claim that DirecTV
sends a full bitrate ATSC datastream)
regardless of the format encoding.
So: ~8gb/hour applies to 1920x1080i HDTV.

Some software DVD players on a high end PCs
can playback ATSC datastreams.

It is possible that DirecTV sends channel 199
in some proprietary format, but it is certainly
worth a try to see if we can record, extract
and make it playable.

[HDTiVo]

I used mvchannels.tcl to bring up chan 199 (HDnet)
on the program guide.

When the channels is tuned the current program
schedule shows up but then a
"Channel not available" bar flashes on the
bottom of the screen. It seems like the
DSR6000 is trying to tune the channel, then
fails, then retries in a loop.

Since this is an HD channel, I wouldn't expect
it to be able to display anything, but I was
hoping that it would at least allow me to
record the datastream for later extraction.

If I hit the "record" button it just gives
me the TiVo "bong" noise.

Any ideas or is it time to give up?

[Juppers]

You can tune the HD channels, but they will make your unit rather unhappy, typically ending in a restart. Guide data should be simple enough though. The trick will be making it always stay on the background tuner so the decoder doesn't puke on itself. I also doubt the UI record functions will work. Maybe a TiVoweb scheduled recording, or a creative use of DT and channel definition updating. Like move the guide information to a normal channel you never watch, then dt the HD channel onto the background tuner so it grabs that stream instead of the normal stream. This does deserve some more conjecture and experimentation. I have been putting off the decryption mod til my turbonet arrives. Guess I need to go ahead and add that one.

[HDTiVo]

If I schedule a "future" recording it does
put it in the Todo list, and the program
shows up in "now playing" for the first
minute when showtime comes on but after a
minute it just deletes the entry and gives up.

[lsmod]

Originally posted by HDTiVo
~16gb for 2 hours is about right for
a 2 hour movie in HDTV.

The ATSC standard specifies 19.3Mbit/sec
for broadcast (and some claim that DirecTV
sends a full bitrate ATSC datastream)
regardless of the format encoding.
So: ~8gb/hour applies to 1920x1080i HDTV.


My experience with a HiPix card and a Dish5000/HDTV Modulator tells me that Dish sends about 10-15Mb/s for HBO and Showtime, more for KCBS-DT (LA) when they're carrying HD.

19.3 is an absolute max, but I'd guess that actual programming will be less than that. And neither Dish nor Direct are sending ATSC (which is a transport specification), but they also aren't rate-shaping or re-encoding the HD MPEG-2 programs. AFAIK, that 10-15Mb/s is what HBO and SHO are uplinking. (It certainly jives with what I saw when I played with BUD's for a living. ;)

As to 199 being a proprietary format, it is, but so is the rest of DirecTV.

Let me say this differently. All DTV programming is MPEG-2 compressed, but the transport is proprietary. (This is the core of the extraction work.) HD is no different, just more data to paint more pixels.

-Z

[koreth]

I'd love to be able to extract the HD stream, put all the appropriate ATSC headers and filler in, and feed it to my HiPix card as a series of .ts files. If this can be made to work it'll be quite cool.

I pay DirecTV for HBO; does anyone know if that includes HBO's HD feed, or is there an extra charge for HD? (I know there are ways around paying, but I'm not interested in that.)

[HDTiVo]

You should be able to get the HD feed (ch509)
if you subscribe to the HBO package.

Some people in fact are getting HD-HBO even
though they didn't subscribe to HBO at all.

[lsmod]

Originally posted by koreth
I'd love to be able to extract the HD stream, put all the appropriate ATSC headers and filler in, and feed it to my HiPix card as a series of .ts files. If this can be made to work it'll be quite cool.


This, obviously, is the holy grail. It would mean that the last unrecordable HD feed (HDNet) was within my reach. ;)

There has been some implication that the HiPix doesn't really need the stream padded out to 19.3Mb/s. It probably does need a valid ATSC transport, though there was at least some effort towards using it for DVD playback at some point. Check the HTPC forum over at AVS Forum (http://www.avsforum.com/).


I pay DirecTV for HBO; does anyone know if that includes HBO's HD feed, or is there an extra charge for HD? (I know there are ways around paying, but I'm not interested in that.)

There's no extra charge for HBOHD or for HDNet. For a while there was a DirecTV Limited package that was like $8/mo that got you a handful of channels including HDNet. This was the choice of the HD fanatic, since you could get HBO, SHO, and CBS from Dish and HDNet from Direct.

I first signed up for DirecTV with a DTC100 as my receiver, and "HDTV" shows up if I look at my account online. So you might have to call them and add it. No idea whether they'll trip on adding HD if you don't have an HD capable IRD.

-Z

[MrBob]

Being new here and having done a search on HDTV I found some very interesting information here. But I have a basic question I hope someone can help me with. I have an Sony 43" HDTV. I receive my picture from a $49 roof top ant. I am in Minneapolis Minn and some of the TV channels are tran in HD. My question is I would like to time shift some of the programs. Is the TiVo the anwser? Can I buy an TiVo and put it in line between my HD encoder and my TV and store the HD information for playback later? Input?

[BubbaJ]

AFAIK there aren't and commercial HD PVRs yet.

Your best bet is to get a computer, big hard drive, and an HD tuner should be less than a grand total. even then, you won't be able to time shift a whole lot of true HD stuff. (most of what's coming over isn't true HD yet, so not really a big deal)

[AlphaWolf]

on a standalone tivo this would be impossible, the mpeg encoder simply wouldnt accept anything above 800x600 resolution.

On a dtivo this is possible because it doesnt encode the video, just stores it. So to answer your question, not likely, the only possible way would be to get it from tivo is through your directv streams.

One technical concern I have though, are modern hard drives fast enough to store high definition content? Possibly a 7200 rpm, but with a 5400 rpm drive, I would think 20 gigabytes in 2 hours is pushing it a little? I am no expert on the specs, its possibly well within range but just asking.

[lsmod]

I have the same 80GB D540X on ATA/33 in my HD-tuner PC as I have in the DTivo. It will be fine.

HD is sent at a maximum of 19.3Mb/s, and the HBO feed (as sent by Dish, but I don't think either D* or E* are doing any rate shaping) is only 15Mb/s at best. Most cheap 5400rpm drives can sustain 10 times that.

The issue is getting the tivo to record the stream without trying to play it. I got as far as trying to find a current channelmap.txt before I ran out of time the other night. (channelmap is required for dt to tune by channel)

-Z

[HDTiVo]

Yes, run of the mill 5400RPM IDE drives are
plenty fast enough to record ATSC HD content.

====

I got my DirecTiVo to show channel 199 in the
lineup and I can hit the "record" button and
it tries to record the show.

If I go to "now playing" I see the HD program
and a red dot indicating recording, but then
about 1 minute later the recording stops
and the show disappears. I think some part
of the DTiVo code checks that a recording
is working and decides that the HD show is
"invalid" and it aborts the recording.

I don't have the time or energy to try hacking
"myworld" (or whatever) to fix this right now
so I am hoping someone else will do it.

[BubbaJ]

hopefully suitable procedure for recording HD (modified not to show on screen) not tested

use a 2.5 machine, with dual tuners enabled
start 2 non HD programs, one recording in the background, the other playing in the forground
use dt to switch the channel recording in the background to a HD feed, if the channel you are watching changes, you hit the wrong tuner.

if doing this doesn't work, then the tivo probably has a bottleneck somewhere. it could be the 5505, the mediaswitch, or even possibly some overhead on the ppc..

[TheDoctor]

If you play around some with SimpleFpgaRecord on a Dtivo, it can be used to record directly to MFS bypassing many of the normal checks. I have not played with it in months, but I know that it takes many of the same arguments as dt. If I remember correctly I was able to use with the second tuner under 2.0, (they had to test it with something before they left the factory.) I was able to verify that short NTSC streams were recorded corectly.

The RecordForever script gives some clues as to usage. The ext2 path filename contains the fsid number. The mfs path name determines where the stream is stored.

[TheDoctor]

under 2.0

-i1 is tuner 2


bash-2.02# /tvbin/SimpleFpgaRecord -i1 /movie1 354 1000
Debug Pid: 171
THE CHANNEL NUMBER IS :354
contiguous memory addr 0x80186000
contiguous memory length 2621440
contig memory virt addr = 0x30148000
/movie1 354 1000
/movie1 354 1000
/movie1 354 1000
Successfully Created Writer Transform

I broke recording aftedr a few minutes... machine rebooted... when it recovered
I had...

mls output:

movie1 tyStream 321834 04/11/02 20:08 131072 x 1024(0)

Valid stream, wrong channel (expected since channel map is out of date.)

tried again with smaller size...

bash-2.02# /tvbin/SimpleFpgaRecord -i1 /movie1 354 10
Debug Pid: 189
THE CHANNEL NUMBER IS :354
contiguous memory addr 0x80186000
contiguous memory length 2621440
contig memory virt addr = 0x30148000
/movie1 354 10
Successfully Created Writer Transform

Broke after a minute or so and machine rebooted, got...

Directory of / starting at 'a*'

Name Type FsId Date Time Size
---- ---- ---- ---- ---- ----
movie1 tyStream 322222 04/11/02 20:26 131072 x 16(0)

Stream does appear to be recording something before running into an old stream. The size variable appears to be chunk count.
Hope the above may be of some help.

[AlphaWolf]

I am curious as to what limits the directivo can handle so far as the recording videostream goes. If echostar and dtv merge, could a software update possibly make directivos be compatible with dishnet (without reguard to the access card)?

[mrblack51]

good question. hardware wise, i would think yes. the reason being that both dtv and dish use the sti5500 in their receivers (specifically, the rca420re uses one, as do the 2700s and a few others AFAIK). in any event, presuming the tuner hardware would work for both (not sure on that one, the lnbs are cross compatible, but dtv and dish use different methods to switch between satellites), it should be possible. obviously a software rewrite would be required to add the needed functionality, as well as the compatibility stuff.

overall, yes in theory, but i doubt they would do that instead of just doing a full hardware swapout

[AlphaWolf]

I just made an attempt at this and got some pretty strange results. I set a manual recording for shrek on HBOH, fired up jdiners tytool, and began extracting while it was recording (copied the resulting m2a/m2v files elsewhere so that I could play them while it was still extracting). Turned out that instead I ended up extracting a movie called "bring it on" (which I have never heard of, and the split files were called Shrek-.m2v and Shrek-.m2a) on an encore channel..If I switch to the tuner thats recording the HD feed (supposedly), in the info box it says that its being recorded (with a blank screen too), but then theres that directv message box at the bottom that says channel unavailable. I wonder how the tuner got thrown off to an encore channel? (BTW, I also made an attempt on channel 199, and ended up with some unexpected 480x480 recording)

[zx7r]

Would it be benefiicial to maybe turn off the 2nd tuner and try recording a HD channel with only 1 tuner? I imagine the movie that you did manage to capture "Bring it on" was 480x480?


zx7r

[qtipwax]

There seems to be some fox sports channels that are in HD format also. I watch alot of baseball and the HD sign has started to appear on some of the games. The last one I recall was Houston vs Seattle. Don't know if it was the Houston area fox or the Seattle area fox that was transmitting.

Qtip

[mrblack51]

Originally posted by qtipwax
There seems to be some fox sports channels that are in HD format also. I watch alot of baseball and the HD sign has started to appear on some of the games. The last one I recall was Houston vs Seattle. Don't know if it was the Houston area fox or the Seattle area fox that was transmitting.

Qtip

um, dtv only carries 4 HD chans: showtime, HBO, HDnet, and i think Discovery HD (maybe not). regardless, the only way you wont see HD on fox sports net for a while unless you can pull it in OTA.

[HDTiVo]

HDnet has some sort of deal with Fox sports
to cover some of their games in HD
(and use their scoreboard overlays).

If it was in HD then it was chan 199/HDnet.
There is no Fox-HD channel on DTV.

I really wish this manual DTiVo recording
would work on the HD channels.

I got the same "wrong channel" recordings
on my tests. It seems like we have such
a good idea and are "so close", but alas
doomed to failure.

[AlphaWolf]

So can anybody come up with any technical reasons why this could still be possible? So far it looks to me like we have all of the hardware needed in a tivo, but getting the software to get the hardware to do the right things is an issue.

[mrblack51]

as far as i can tell, a channel is a channel. but, as evidenced by the music channels, some are treaded differently from the start. the question is whether the 'DTV half' of the equation is preventing the tuning to the HD chans, or if its the TiVo interface that is doing it