[RealDealNeil]

So how does the RPi work with the new PVR feature? I have a MythTV backend and have so far been running xbmc and mythfrontend and alternating depending on what i wanted to watch, now with the new PVR functionality i have a combined solution that works great but before i would go spending money on a RPi no matter how cheap it is it would be nice to know how well the PVR addons work with this thing, because the stuff coming from MythTV unlike recoded stuff is basicly "raw" from what i understand so the 1080i streams are much heavier than the x264 stuff you normaly would watch with XBMC.

can anyone shed some light on this? am i making a poor assumption when i think streaming HDTV is much heavier than streaming a Bluray rip?

I'm running a MediaPortal backend. My RPi (using OpenElec) can play channels in 1080i no problem. Channels in 720p pause to buffer about every 10s. I have yet to get to the bottom of this, but I suspect it's because 1080i is easier to decode (it's interlaced and sends only half the horizontal lines every frame). I'm not sure if overclocking will help or future updates to OpenElec or RPi.

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[Vertigo]

It probably has nothing to do with the resolution, but everything with the audio codec. My guess is that those 720p channels include a DTS or AC3 multichannel audio track, and you are letting the Pi decode and downmix that. Thats when it struggles. 720p shouldnt be a problem when using audio passthrough, assuming you purchased and installed the mpeg2 codec which those streams most likely use.

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[Vertigo]

Lucky you. 99% of the channels here are 2 channel PCM :/

Anyway, Ive not had trouble with 5.1 AC3 decoding myself yet, but I have read it can stretch what the Pi is capable off. Perhaps only in combination with mpeg2 (rather than x264 which I use almost always) ?
In this cause though, I guess its more likely the 1080i recordings have a AC3 track or less, and the 720p recs a DTS track. And that would cause stuttering on a Pi when not passing through.

[blatantninja]

Vertigo, awesome write up! I think you have sold me on at least giving this a shot!

- the Pi is not always fast enough to transcode DTS or Dolby Digital 5.1 (AC3) to stereo on the fly, but it has no problems passing through these codecs over HDMI to a DTS or AC3 decoder/receiver. If you have an HDMI receiver (or TV) that allows these audio codecs, you will be fine (the work is done by the AVR decoder). If you dont have that hardware, there isnt too much point in using a DTS track, so if possible, you should select a stereo or AAC track instead. Most DTS/AC3 media will have such an audio track.

I am woefully ignorant when it comes to audio, so I have some probably basic questions.

1) DTS and Dolby are listed there, but can XBMC on the Raspberry Pi handle TrueHD and DTS-HD? I would just be passing through on HDMI to a TV (that handles them) or AVR.

2) If the answer to 1 is no, does XMBC automatically select a different audio track that it can handle?

One more little known feature of the Pi that deserves highlighting, is its built-in HDMI CEC capability. Unlike any x86 videocard Im aware off, the Pi can send and receive HDMI CEC commands. This allow you to use the remote of another HDMI CEC compliant machine, like TV or AVR to control XBMC. On x86 you can achieve the same only buy purchasing a Pulse-Eight adapter kit. HDMI CEC is also known as Easylink, Vierra Link, BRAVIA Sync, Anynet+, etc.

This is really great, but again a question: Is this functionality working in XBMC? I would love to just be able to use my TV remote (Its a Samsung with Anynet+).

- The network interface is 100T.
Even using USB to Ethernet adapters, you will still be limited to 100T. It wont do gigabit ethernet.

100T should be enough for video though I would think.

Thanks again for this write up!

[Vertigo]

I am woefully ignorant when it comes to audio, so I have some probably basic questions.

1) DTS and Dolby are listed there, but can XBMC on the Raspberry Pi handle TrueHD and DTS-HD? I would just be passing through on HDMI to a TV (that handles them) or AVR.

AFAIK, not yet. The hardware should be capable of it, but the software doesnt support it for now.

2) If the answer to 1 is no, does XMBC automatically select a different audio track that it can handle?

Someone correct me if I got this wrong, but as I understand it, for DTS-HD it wont be a problem, as the Pi will just passthrough the DTS core stream (DTS-HD/MA is actually an additional stream which contains corrections to the core stream, and the Pi will ignore that). Your AVR will just see a DTS stream.

For Dolby TrueHD, there is no "core" stream, so XBMC would have to downmix it. I dont know if its able to do that fast enough; its possible, but I wouldnt necessarily count on it. I also dont think XBMC will automagically pick another audio stream, my guess is you would have to select it manually.

This is really great, but again a question: Is this functionality working in XBMC? I would love to just be able to use my TV remote (Its a Samsung with Anynet+).

In theory, yes. Though again, my TV supports almost nothing HDMI CEC, so I havent been able to verify it.
I will be installing a Pi at a friend in a few days, and he has a HDMI CEC compliant TV and AVR, so I will know then.

Thanks again for this write up!

You are most welcome.

[wejones]

Thanks for what seems to be a very informative thread.
I'm new to XBMC , relatively new to the Raspberry pi, and only moderately experienced with Unix/Linux, but not with A/V topics, so I really don't know what I'm doing.
I recently installed XBMC on my Raspberry pi. I first put it on an SD card with Arch Linux. I then put it on an SD card that I recently installed the Wheezy system. XBMC seemed to install OK on both systems (although it was an effort on Arch Linux), and I was able to run it, however when I tried to play an MPEG4 video file, the AC3 audio played fine through the HDMI output, but I didn't get video. It was the same on both systems. All I got was a small thumbprint of the video down at the bottom right, which was frozen on the first frame of the video.
Previous to trying XBMC, I had tried playing the same file with both VLC and mplayer2. Mplayer 2 played the video at about 1/30 normal speed, and didn't play any audio, VLC just refused to play anything.
I was starting to think that the RPi just wasn't capable of playing medium bitrate HD (it was a 12.5 Mbps H264 video recorded off a PBS sat feed), however after reading this thread, it sounds like it should be able to play the video, so I must be doing something wrong.
I've read that the RPi has hardware acceleration for MPEG4, but I'm wondering if something has to be done to enable it?
I have the OS on a class 10 SD card that is supposed to be capable of 20 MBps, although when transferring the OS to the card, it seemed to be only going at about 6 or 7 MBps. So I thought that perhaps I would put the video file on a USB thumbdrive, but that didn't help. I know that MPEG2 hardware acceleration isn't enabled without a fee, but I tried a similar mpeg2 file, and it behaved in a similar manner, which made me think that the problem must be that the MPEG4 acceleration isn't enabled, but I have no idea of how to tell if that's the case or not.
Is there something that needs to be done to enable mpeg4 acceleration? Or any other thing I've omitted that would cause my problems?

Thanks in advance.

[Dilligaf]

@ wejones being a Linux newbie your best bet would be to install an XBMC distro be it Raspbmc, OpenElect or Xbian. Personally I use Raspbmc. I don't want to start another "distro war" here, try them all and see which one fits your needs. The xbmc debs for the regular Linux desktop distros will never match the performance of a system that is tuned to run XBMC

[Vertigo]

Is there something that needs to be done to enable mpeg4 acceleration? Or any other thing I've omitted that would cause my problems?

What Dilligaf said (my vote goes to Openelec, but whatever floats your boat).
Its probably gpu driver issue with Arch,

[wejones]

Thanks. I did try to download one of those, I think it was the Raspbmc, however what downloaded was only a stripped down loader version that tried to go on the internet to get the rest. Problem is, I have limited internet bandwidth, and for big files, I take my laptop to a nearby town where they have free wireless, and I can't take the RPi, so I need a full image. I will look harder though, and at the other two mentioned above.
Can I ask just how high a bitrate the RPi can play with XBMC, both via MPEG4 and MPEG2 with the license enabled? Most of the video I play is that 12.5 Mbps MPEG4, but I also occasionally play video that's over twice that.
Also, the RPi I have was given to me as a gift, and it is not the newest one with additional RAM. I've ordered one of the newer ones, and I'm curious if the additional ram might help with the issues I observed. Also, can I assume from the above that with XBMC there isn't anything I need to do to enable the hardware acceleration?
Thanks.

[Vertigo]

Thanks. I did try to download one of those, I think it was the Raspbmc, however what downloaded was only a stripped down loader version that tried to go on the internet to get the rest. Problem is, I have limited internet bandwidth, and for big files, I take my laptop to a nearby town where they have free wireless, and I can't take the RPi, so I need a full image. I will look harder though, and at the other two mentioned above.

Yeah, raspbmc does that, although you can download a standalone installer, its right on the frontpage. Openelec will only give you a full installer, at least for linux.

Can I ask just how high a bitrate the RPi can play with XBMC, both via MPEG4 and MPEG2 with the license enabled? Most of the video I play is that 12.5 Mbps MPEG4, but I also occasionally play video that's over twice that.

Im not sure about mpeg2, but mpeg4 will be up to ~50Mbps.

Also, the RPi I have was given to me as a gift, and it is not the newest one with additional RAM. I've ordered one of the newer ones, and I'm curious if the additional ram might help with the issues I observed.

The extra RAM doesnt make too much difference. Im pretty sure what you encountered was Arch specific.
As for the rev2, one major improvement over the rev1 (with 256Mb) is improved analog audio. On the rev1 that was pretty horrendous from what I read, but if you use HDMI audio it doesnt matter.

Also, can I assume from the above that with XBMC there isn't anything I need to do to enable the hardware acceleration?

Nope. Aside from enabling the mpeg2 license if you need it.

[wejones]

Thanks. I did try to download one of those, I think it was the Raspbmc, however what downloaded was only a stripped down loader version that tried to go on the internet to get the rest. .....

Yeah, raspbmc does that, although you can download a standalone installer, its right on the frontpage. Openelec will only give you a full installer, at least for linux.

OK, I guess I must have missed the link for the full image. I'll probably download both or all three, then give them all a try. Although it was -16 this morning, and I may wait till it warms up a bit before going out with my laptop.

Can I ask just how high a bitrate the RPi can play with XBMC, both via MPEG4 and MPEG2 with the license enabled? ........

Im not sure about mpeg2, but mpeg4 will be up to ~50Mbps.

Well that's encouraging. I think the highest MPEG4 bitrate I'd do would be about 23.5 Mbps. MPEG2 sometimes goes above 40. You don't happen to know if the RPi / XBMC can do 4.2.2 video via the MPEG2 license? I'm going to get the license once my new RPi comes.

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The extra RAM doesnt make too much difference. Im pretty sure what you encountered was Arch specific.
As for the rev2, one major improvement over the rev1 (with 256Mb) is improved analog audio. On the rev1 that was pretty horrendous from what I read, but if you use HDMI audio it doesnt matter.

Also, can I assume from the above that with XBMC there isn't anything I need to do to enable the hardware acceleration?

Nope. Aside from enabling the mpeg2 license if you need it.

Thanks for the info on the above. This has been encouraging. I was just about to give up when I ran across this thread. I can do most everything already via my desktop computers, but this little Raspberry thing is so neat, and it might allow me to turn off one of my desktop computers and save some electricity.

Thanks.

[Vertigo]

I dont even know what 4.2.2 is, but if you can point me to a sample video, I can try it for you.

edit: scratch that, I dont have an mpeg2 license. Maybe Ill order one..

BTW, while you are downloading, grab this skin:
http://forum.xbmc.org/showthread.php?tid=135468
(quartz reloaded)

Its supposedly not compatible with Frodo, so it doesnt install from zip, but it works without a hitch if you extract the archive directly to the sdcard to /storage/.xbmc//addons
Great looking skin and works pretty well on the Pi.

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