This is really nice work. Just wondering, you were able to setup a full MBE/FE with the F27 install? You could record and view from the HDHR? Is this a LIVETV able? or just record and playback. (I've only thought of the ATV as a possible HD frontend.)

I had never thought of a KM FE/BE on ATV. With the lack PCI and Firewire, it would be limited to network or USB tuners. An ATV FE was all I was considering at first also. LiveTV playback with respect to FE CPU load is no different than recorded playback, correct?

[quote="Too Many Secrets"]This is really nice work. Just wondering, you were able to setup a full MBE/FE with the F27 install? You could record and view from the HDHR? Is this a LIVETV able? or just record and playback. (I've only thought of the ATV as a possible HD frontend.)[/quote]

Yes, 1st install was combined front/backend. Seemed to be fine. The 2.5 disk I'm running is an older 30GB 4200 rpm disk. hdparams says 20MB/sec. My mainline disk is a newer 100GB 7200 rpm and hdparams say 40MB/sec.

Disk speed might be important for swap but not so important for HD content record/playback. The bit-rate is just not that high compared to 20MB/sec.

Since HD content runs 4-6 GB per hour, disk size might be an issue. That could be extended with a USB hub and external USB disks for video content storage. I've run a mythfrontend from an external USB disk before and it was fine.

LiveTV with myth and HD content is always a little doggy even on fast silicon. That's just the way MythTV works. The Myth devs do not really care about LiveTV except to say WFM.

While a combined front/back is possible, separate boxes are better. Once you combine mysql creating seektables, commercial strip and transcoding, the backend load is going to jump.

A lot depends on your content, SD content -- no problem. Toss HD content into the mix and you have to watch the cpu loading.

Beside, you really don't want the backend in the media room anyway. No one wants to hear disks making noise when watching a movie. A separate backend is pretty easy to create with any old PC hardware. You don't have to worry about video play back issues so pretty much any old cpu with a bunch of disks will do.

My mainline backend is a beefy Core2 Duo with about 3TB of storage space. The cpu was picked not for record/playback but MythWeb and transcoding to a format of an IPod Touch.

I will be using an older PC that I inherited as a backend and the ATV as a frontend only.

It is extremely unfortunate to here that the devs don't care about LiveTV playback. If what you say is true, then I would need another tuner at each TV just for LiveTV.

MythTV is developed by passionate people and I am extremely grateful. I don't want to seem like I am complaining at all, but this raises a question. What do people do when they want to watch LiveTV?

A scant few Mythtv devs use LiveTV. Usually the response is "sorry, change your viewing habits".

LiveTV does work, you just have to follow a few tips. Don't try to browse LiveTV channels directly, it's like watching paint dry. Browse using the channel guide. Then select what you want to watch from there. I have Dish Network and long ago changed my browsing method to using the channel guide instead of flicking channels. It was just too slow.

LiveTV on Myth works like this,

1) you select a channel on the frontend
2) backend changes to that channel and starts a recording session
3) backend creates video file and starts writing content to it after buffering a few seconds.
4) frontend finally sees the file is present through database access
5) frontend buffer a few seconds, then starts decode/display.

The 2) can be a second or so, 3) is a few seconds for buffering and 5) is also a few seconds. This all adds up to 5-10 seconds or more from button press to video displayed. Like watching paint dry.

If the backend recognized that the recording request was LiveTV and did direct i/o instead of buffered i/o, that would eliminate about 1/2 the delay.

We realized this right away with our x-ray spectrum imaging product that is network based. The backend contents need to be blown over the nwtwork and to the disk right away or the frontend sits around waiting for it to appear.

I dont really want to see this thread digress into a LiveTV thread. But for what it's worth, I use HD&SD LiveTV every day (sports, news, etc) and while it's clunky it works with acceptable WAF.

I agree that an ATV isn't ideal for a MBE/FE, but the fact that it can pull it off at all (with an HDHR and sans peppy transcoding) is impressive.

A quiet, small HD FE that is about $200 is most impressive. Just wondering, is the ATV silent or just quiet?

Agreed. no more LiveTV rants.

The AppleTV is pretty quiet. I hear my disk access but it's not the original disk but an much older 2.5 drive. My 100GB 7200 disk is very quiet, I never hear it at all.

I can't test the original AppleTV disk, that's been archived but I might pull it out and use it now or something else. The procedure to restore to an original config is pretty simple if you have a backup of the recovery partition.

Can someone recommend an upgrade procedure for the nvidia driver. I tried this one (http://mysettopbox.tv/phpBB2/viewtopic. ... nvidia+169) going to 169.12 and got the got the original (1.0-9755) back on boot.

I agree! Another thread elsewhere for that topic. Sorry about that. Back to the AppleTV and KM.

Since the AppleTV has 256MB of RAM, would diskless booting have the same slow swap issues as booting from a USB stick?

Don't know if this on the wiki is much different on the nvidia front.

[quote="tombongo"]Since the AppleTV has 256MB of RAM, would diskless booting have the same slow swap issues as booting from a USB stick?[/quote]

diskless would be worse as typically swap is not present (no disk right). There is a way you could put a swap file on say the original "Media" partition and use that as swap. Not tried it.

You really need some type of swap present when using MFE. MFE by itself is 318m virtual with about 105 physical. I see


[code]
Mem: 249884k total, 245672k used, 4212k free, 224k buffers
Swap: 373456k total, 120856k used, 252600k free, 67332k cached

[/code]

when doing MBE/MFE 1080i mpeg2 to a 1080p HDTV, LiveTV. Watching golf masters right now. Testing as they say.

It's more like this

When I did my KM backend streaming HD to two diskless frontends, there wasn't any swapping going on because each frontend had 1GB of RAM. Unfortunately, ATV's RAM can't be upgraded. It is soldered on.

The potential disk noise, although probably very small, is OK with me!

Rebuilding kernel now to add analog audio and Apple IR support.

These will be different patches than what exists on atv-bootloader download section. The 2.6.18 kernel is a little different in structure than 2.6.22 and above.

Just for kicks, doing it with "nice" while watching 1080i mpeg2 LiveTV.

The kernel in R5.5 is already patched for Intel Mac and the AppleTV. That however is as far as I go as I don't have the hardware. If you'd like to kick the tires, let me know via PM.