• zuzu
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  • Registered: 2008-01-14
  • Posts: 1

Topic: 480p HDTV with MythTV and HDHomeRun network tuner?

I have a SiliconDust HDHomeRun (HDHR) network ATSC/QAM dual tuner for HDTV, and I'm wondering if anyone has tried or thought of installing MythTV (or just the frontend?) onto a Chumby for playback of 480p (SD) digital television?

480p MPEG-2 transport streams typically run about 2Mbps, which should fit within the bandwidth of 802.11g wireless of the Chumby.

but is the ARM processor powerful enough to decode 480p streams in real time?

has anyone tried this?

  • From: Cincinnati, OH
  • Registered: 2007-10-09
  • Posts: 78

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

The display is only 320x240, so throwing 480p at it would be overkill, wouldn't it?  And that's assuming the Chumby would be able to handle an mpeg2 or mpeg4 stream, which I don't think it would.  Other folks can correct me if I'm wrong, but if you want the Chumby to stream video, it'll need to be flash video at no higher than 320x240 resolution. 

AFAIK the best solution for streaming your own content in flash video would be Orb.  Someone smarter than I just needs to develop a widget or hack that will allow the Chumby to accept the .flv stream from Orb.

Chumby birthdate: 10/11/07
  • Duane
  • Duane
  • Blue Octy
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  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,197

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

Even though the wifi is 802.11g, it's connected to a USB 1.1 port, so there's a fundamental limit on the bandwidth available.

The 350MHz ARM926EJ-S processor in the chumby is very likely not going to be able to decode and scale 480p video in realtime - most embedded devices of this class have specialized coprocessors to decode video.

Duane's Website

  • Registered: 2007-12-26
  • Posts: 115

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

So does this mean that the USB ports on the chumby are 1.1 ports and NOT 2.0 ports?
On the wiki it says that all three USB ports in the chumby are 2.0
Wouldn't a usb 2.0 port be strong enough>
That said.
A little USB accessory TV tuner for the Chumby would be a cool thing to have. I have one for my laptop which receives HDTV and it is extremely cool.
I am quite sure the chumby couldn't handle HDTV but an analog tv signal decoded by a usb key thingy may be another story...
Just thinking out loud here.
Yaesumofo


Duane wrote:

Even though the wifi is 802.11g, it's connected to a USB 1.1 port, so there's a fundamental limit on the bandwidth available.

The 350MHz ARM926EJ-S processor in the chumby is very likely not going to be able to decode and scale 480p video in real time - most embedded devices of this class have specialized coprocessors to decode video.

A Chumby in hand is worth 20 in the Wherehouse.
  • From: Boston
  • Registered: 2007-06-05
  • Posts: 61

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

It's my understanding that a lot of the USB TV-tuners are touchy with Linux, if they work at all. I think many of them use software decoders as opposed to hardware decoders... (I could be wrong on this...) which of course would be another sticking point.

Running it as a mythfrontend would be cool, though.  (I am really loving our new myth set up).

shoe's Website

  • Duane
  • Duane
  • Blue Octy
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  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,197

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

Sorry, I misspoke, they're actually what the standard calls "USB 2.0 Full Speed", which means they operate at a maximum 12Mbit/s ( 1.5 MB/s).

Duane's Website

  • From: Cincinnati, OH
  • Registered: 2007-10-09
  • Posts: 78

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

shoe wrote:

It's my understanding that a lot of the USB TV-tuners are touchy with Linux, if they work at all. I think many of them use software decoders as opposed to hardware decoders... (I could be wrong on this...) which of course would be another sticking point.

Running it as a mythfrontend would be cool, though.  (I am really loving our new myth set up).

I think most (if not all) of the newer USB tuners will encode the MPEG-2 stream, so beyond the sticky problem with drivers, the Chumby would still have to decode MPEG-2 (can it?).  I doubt one exists, but a Linux-friendly USB TV Tuner that would encode to flash video format would be ideal, from what I understand the Chumby's capabilities to be.

Absent that, the most workable solution is probably sending an .flv stream from a PC that has a TV tuner.  A simple MythTV or BeyondTV, or other MCE-type front end would be quite cool-- I'd be tempted to put a Chumby in every room of the house.

Chumby birthdate: 10/11/07
  • Registered: 2007-12-26
  • Posts: 115

Re: 480p HDTV with MythTV and HDHomeRun network tuner?

Duane wrote:

Sorry, I misspoke, they're actually what the standard calls "USB 2.0 Full Speed", which means they operate at a maximum 12Mbit/s ( 1.5 MB/s).

Since when? the effective rate reaches at 40MBps or 320Mbps for bulk transfer on a USB 2.0.

Some how I don't get this.
Why not be open to ideas which make the chumby more useful insted of attempting to quash tham?



REad this for USB naming conventions:

http://www.usb.org/developers/packaging/

Yaesumofo

A Chumby in hand is worth 20 in the Wherehouse.