How-To: MacOS X Firewire HDTV recording - Page 3

The 6200 can be set up to change channels at a specific time for a specific duration. I use the MyHD card to playback the .m2t files without any problem. I recommend using a Firewire external drive to capture the files via the Mac and network it with the computer running MyHD.

Two alarms on one event: that's great, especially in combination with Watson TV plug-in.

Someone mentioned using the Mac as a remote control using iRed and the related hardware. This software can help write the scripts to change channels using iCal. I suppose a third alarm can be added? This would be useful in those cities where the date and time info sent by the stations are unreliable when using the STB to set up timed recordings.

Joe, could you elaborate on how the 6200 can be set up to change channels. Is this a function of the Mac software, something that is done with the 6200 OSD, or other method? If it could be added to the iCal functions as you mention, then we are almost there. The only better thing would be a TitanTV helper app for the Mac as the previous poster mentioned.

I have the MyHD as well. Have you ever tried to record to the PC's hard drive over a 100base-T network? I have my PC drives shared with the Mac, but do not currently have a firewire drive. I also have a gig-E switch, but have not changed from 100meg to gig-E yet. Could go gig if that would make a difference.

I also notice MyHD has a D-VHS option. Does this somehow control the Mac-6200 connection, or do you just need to play the captured file on the MyHD the same way you would a .TS captured by MyHD?

IF the STB responds to the Tuner protocols, you can use a Mac *now* to change the channel. Not easily of course...

AVCBrowser, in the Device Controller section, has a way to enter a hexidecimal AV/C command. You just need to figure out the command, the target address, the arguments -- encode that into hex -- and you got it!

Here's the document you need to figure this out...

AVC Digital Interface Command Set General Specification v3.0

According to one site, this has been superceded by two documents: AV/C Digital Interface Command Set General Specification Version 4.0 and the AV/C Descriptor Mechanism Specification Version 1.0 documents. One site sells v4.0 for a whopping $300 smackers. But many of the commands I tried from v3.0 got working replies.

This ain't for the faint of heart. You need to know hexidecimal, and bit encoding. It's pretty freakin ugly. And I had to reset my TV after messin' around with this, so make sure you target your target!

If you set VirtualDVHS to AVC Verbose Logging, you can see the actual hexidecimal AVC commands. I'll post some examples when I get home tonight, if anyone is curious.

If anyone else finds an easy reference to AVC commands + hex equivalents, please post it.

-Pie

I doubt the 6200 has a tuner subunit, but it could have a panel subunit, supporting the pass-through command, with the "deterministic tune" capability.

Can somebody with a functional FireWire equiped STB, use AVCBrowser to issue the "Subunit Info" command (one of the buttons on the GUI interface), and post the bytes from the response packet? This will tell us what subunits are part of their AV/C unit.

I guess what I mean is, I doubt the 6200 has a "fully implemented" tuner subunit. It may report it has a tuner subunit (via subunit info command) for device discovery reasons, but it is unlikely that its tuner subunit responds to the commands specified in the tuner subunit specification. That is a pretty complex subunit to implement.

Using the remote for the 6200, (recalling from memory) press menu and then select main menu/setup/timers to get to the 6200 screen to schedule channel changes.

From my Motorola 6200

The 28 specifies a tuner subunit
The 48 specifies a panel subunit

So it looks like your 6200 does indeed have a panel subunit.

While the tuner subunit is there only for device matching, the panel subunit possibly does have some useful functionality with regards to FireWire driven channel changing.

There are two types of panel subunit implementations, direct mode, and indirect mode.

Direct mode is the more complex mode, where the target device (STB) can actually export a full, multi-page GUI control panel (with buttons, icons, sliders, etc.) to the controller (DTV), then the DTV sends "USER ACTION" commands to the STB when the user interacts with the various elements of the on-screen panel. It's possible, but unlikely that this device implements a direct-mode panel subunit. You can test to see if this devices supports a direct-mode panel subunit by hooking it to a Mits TV (with FireWire), and selecting it as the current device, and pushing the "Device Menu" on the Mits remote.

The other type of panel subunit, the indirect-mode, is a much simpler implementation. This mode supports only one AV/C command, the "PASS-THROUGH" command, that represents button press/release from a remote-control being "passed through" the FireWire cable to the target device.

In the latest AV/C panel specification (currently 1.21), new operation_ids were added for deterministic functionality. Previous versions of the spec had "channel up" and "channel down", but now we have the "tune" operation where you specify the exact channel to tune to (a much more useful method of handling this).

AVCBrowser can be used to send commands to the panel subunit. Without going in to great detail here, you could try:

00487CE70400xxFFFF,

where xx is the channel number from 0x00 to 0xFF (in hex).

Note that AV/C targets can be fussy with regards to the exact values of operands in an AV/C command (vs. what it is expecting), so if that doesn't work, the device may reject the command, yet still support the tune functionality if a few of the bytes are changed (for example, the reserved bytes FFFF, may need to be 0000). There are other changes that may need to be made to other bytes as well. Since I don't have one of these cool boxes, I cannot experiment for myself, and it would probably require that you have access to the 1394TA spec to know what to tweak from there.

Good luck.

FriarWyer:

So, this AV/C command, 00487CE70400B3FFFF, should tune the 6200 to channel 179? Could this command, if slightly off, mess things up? Is there a restore hex command just in case? So, I can then substitute the 0000 for the FFFF.

There are 30 input plugs on the 6200. The values for Online, Broadcast, Point to Point and Channel are 1,1,30 and 45 respectively. Is there an AV/C command to make the 6200 decode and display a .m2t file that is to be played via VirtualDVHS. Simply clicking on Connect under the Input Plug of AVC Browser after setting the channel to 45 in both AVC Browser and the Player side of VirtualDVHS does not cause the 6200 to decode and display the .m2t file.

Do you have any ideas on playback through the 6200?

Thanks for the external Firewire drive idea as it has practically eliminated the number of overruns.

There's a separate AV/C Tuner specification.
It uses AVC Descriptors / objects and is a pain in the ass to implement as mentioned by someone else earlier.
I think it is highly unlikely that anyone will be able to "control the tuner" using hex commands from AVCBrowser.
Better off writing extra code for VirtualDVHS to set/change tuner channels.

I have the specifications, if someone is seriously interested in this, contact me I guess.

If the above AV/C command doesn't work (rejected by the device), it won't have any bad side-effects, it just won't do anything. Nothing with this particular AV/C command should have lasting effects on the box.

Note that there are actually 12-bits of channel number in this command (the preceding 0 could also be used to extend this to up to 4095 channels).

Regarding sending a FireWire stream to playback through the 6200, I believe that the "30 input plugs" is misleading. That's actually a bug in AVCBrowser, in that doesn't expect an AV/C device not to implement the "Input Master Plug Register", and misinterprets the fact that the read of the iMPR fails as it having 30 input plugs. In fact, this device doesn't implement ANY isoch input plugs, and therefore currently doesn't have any input capability.

I guess, for now, the solution is to capture the stream from the 6200, then feed the stream to the FireWire enabled TV (using VirtualDVHS, or equivalent). But, if you don't have a FireWire enabled TV (or other STB), I guess you're out of luck (or should I say, buy a Mits ). Maybe some future firmware upgrade to the box could address this, since it obviously has a MPEG2 decoder built in.

FriarWyer,

I gave it a try. This is from the log...

I received a similar response after substituting 0000 for FFFF.



When I click on Input Signal Format...

Thanks for your help on this. I do have a couple of ways to decode these files. For the 6200 to do the work, a firmware update will be needed.

Hello,

I updated http://mac_hdtv_timer.home.comcast.net to reflect some of the great tips posted here at this page .


Pie,

Any luck in finding the # out value in AVC Browser for your SA box?

Joe,

You can make as many alarms as you like on ical for a single event! Pretty nifty!

#out: 1

I'm guessing that's the right value?

-Pie

Yeah! I thought one was awesome in the beginning. The multiple alarms and the Watson plug-in makes set-up even easier.

Yep, 1 is good. Try VirtualDVHS without AVC Browser and see if you can record. If you are getting an empty file, then use AVC Browser. Click on the Connect button under the Output Plug on the AV/C Device window and then click record on VirtualDVHS. You must have VirtualDVHS up and running before you click on Connect. Be sure to read the PDF on initiating connection.

Good luck and it should work especially if you click on the Output Plug Signal Format button on the AV/C Device window and the response is Implemented/Stable.

You will need to set up the transport stream directory as well, before recording.

I do have plans to support the Tira, too. Actually only the IRTrans is supported. Its a matter of interest, though ;-)

Cheers, Robert (developer of iRed)

Just read your updated tips. I see the you say you a 250gig, 8mb cache firewire drive to eliminate overuns. Is 8mb required ? I just picked up an 80gig, 2mb cache firewire drive last night. It was cheapest one I could find. I will test tonight if 2mb cache is enough.

The more I read from the beginning to the latest posting the more I became befuddled as the programming boffins delved deeper into the snags and work-arounds. I am not a computer science graduate but some of the present Mac software programs I deduce as being feasible. However, does any of this relate to using a G5 with Panther for recording HDTV from a satellite TV STB (with no Firewire) in combination with a Sony GWII (again no Firewire). Please advise whether it is feasible, and if not what work-arounds would be needed to make it so. Thanks guys.

Sorry, this stuff depends crucially on the HD signal being in the form of an MPEG2 transport stream. If your STB only has component outputs, that is an uncompressed HD signal which is about 100 times as much data per second as a transport stream which is what you get from a FireWire interface.

Going from transport stream to uncompressed HD is hard enough. Going in the other direction (which is what you would need) is too difficult for current consumer technology.

The good news is that the FCC has a directive that as of April 1 of this year (about a week ago) cable companies are required to provide a FireWire interface on their STB if a customer requests it. I'm sure that is a simplification but you can check other discussions here to get a more accurate status report on this issue. The bad news is that even if your STB has FireWire that does not guarantee it supports all the needed protocols. But it is a good, and necessary, first step.

This may be best for another thread, but since you mention the ruling, I was wondering if it effects Voom (and if not, why not....i.e, what is the thinking in only impacting cable companies?) I am planning a Mac-based set-up to capture premium HD channels, and unfortunately my Adelphia has exactly one HD channel now that I do not already get OTA (HBO.) Voom has about 20. I will look around for other threads on this. Sorry to delve off topic here, you mentioning the ruling got my curiosity up.

This wasn't meant to convey a minimum but an optimum. I think a Firewire drive makes a difference especially at 7200 RPM. A drive with USB 2.0 combined with MacDrive on a Windows machine would let you use the HFS+ formatted drive with a Windows machine if the intent is to use MyHD for decode.

I believe my Maxtor 250 GB, 7200 RBM, FireWire, USB 2.0 was offered as 8 MB cache only.

Like I said I will report tonight on my success. I will be recording the Bruins on INHD2.

My drive is 7200 RPM so hopefully it is enough. How should I format that drive so that I can share it with windows and macos ? I am a mac newbie so if I need to format it there please give me some detailed steps

Now on another note... How 'bout some recommendations on firewire cable? I've searched the net, tons of firewire cables out there... but nobody talking about what's good.

-Pie

>No, firewire is the critical mechanism for moving the stream to and from the Mac. Firewire is only >currently available for OTA and cable not satellite. The upcoming Dish 921 DVR may change that.

Unlike another poster who was going to buy an external Firewire 7200 rpm H/D, I already have one but looks like I'm going to be out of luck anyway. I made a point of checking that before posting my comment, Cliff, and the long awaited Dish 921 DVR does NOT have Firewire, 1394, etc. But even if it did, why even bother if the 921 essentially records satellite HDTV without it ?

Once again, there's that fly in the ointment ! Cable TV companies, not Satellite TV companies. Thanks.