[mythtv-users] Using MythTV files remotely

[Joseph A. Caputo]

On Wednesday 17 September 2003 07:23 am, Timothy.Weaver at at.redbull.com wrote:
> I have scanned the entire history of the mailing list and did not see
> anyone using MythTV the way I intend to use it. As I am currently living in
> Europe without any possibility of satellite or other form of English TV, I
> decided to setup a MythTV box in the USA where I can remotely control it to
> record programs, transfer them to my computer in Europe and watch TV. This
> has some interesting implications.

VERY cool.  Kudos for your ingenuity!


> First some background. I have a PVR-250 in a 2.5Ghz machine with 512MB
> connected to a cable modem. Upstream on the cable modem is around 12KBps.
> This is an important point because my real issue is in finding the optimum
> settings to give me a decent quality file at the lowest possible size. I
> accept that I need to balance quality versus file size. I will be
> transferring the files in the background and will not stream or directly
> access the files, therefore I can accept slightly bigger files in the
> interest of decent quality.
> 
> I have successfully setup the September 16 tarball of ivtv and CVS of
> MythTV remotely and can capture video just fine using "cat /dev/video0 >
> video.mpg". I also have xmltv and MythWeb running and can record shows, so
> I should be able to handle the administration fine from Europe. As I have a
> straight coax into the PVR-250, I did not have to worry about lirc (thank
> god).
> 
> I set MythTV's Default profile to record at 720x480 with audio sampling at
> 32000. I then set the Transcode profile to 480x320 with audio sampling at
> 32000 (as I read the mailing list, the audio sampling must match).
> 
> My questions are:
> 
> 1) Can anyone recommend which settings in MythTV's Transcode profile I
> should use to obtain decent quality for a file size I could live with
> downloading?

That's very subjective, based on your definition of "decent quality" and what 
a 'liveable' file size is.  However, why not try the default MPEG-4 settings 
(bitrate 3300 scaled) with MP3 audio quality 1 (I think that's the highest 
compression, if not then 9).  Then start tweaking from there.


> 2) Is anyone still experiencing lockups with the mythtranscode
> functionality? I need tor research more, but I think this is the cause of
> box lockups I am having.

Can't say, as I don't currently use the transcoder.


> 3) I will be viewing the files on a Windows box.

No, you won't :-)  Seriously, though, I don't know of any way to watch a 
native Myth MPEG-4 recording on a Windows box.  Someone is working on a 
DirectShow driver/plugin, but I don't know if it's in a usable state yet.

> As PVR-250 encodes
> straight to MPEG-2, I can download and watch the MPEG-2 files fine.
> However, the transcoded files to MPEG-4 give me a codec error on Windows
> Media Player and Intervideo WinDVD.

Right; it's not an MPEG-4 file, it's a NuppelVideo file.  The video is 
compressed with an MPEG-4 codec, but it's not an MPEG container as the audio 
is not muxed in, among other things.  AFAIK there is not even a Windows 
player that can handle vanilla NuppelVideo files, let alone Myth's tweaked 
version of the Nuppel format.  You might want to get a Linux box up and 
running.  If you can't install Linux on a box there, try KnoppMyth, which 
lets you run a Myth frontend directly from a bootable CD.

> Is there any way I can confirm the
> transcode is working properly

Yes; play the file back in Myth.

> and also any way to indicate when the
> transcode is completed on a given recording?

Well, there's not notification feature... I think maybe there's a flag in the 
database that indicates if transcoding has been done.  Barring that, I 
believe the existence of a "<program>.nuv.old" file would indicate a 
completed transcode.

> 4) Is there any easy way to identify the connection between the file name
> used on the file system and the actual contents of the file? I know it is
> the time and date in the name. I know I can look it up in the mysql tables.
> But I am looking for something more glamorous and don't want to reinvite
> the wheel .

Again, you probably want a Linux box for this, running a standalone frontend.  
You could try running a cron job on your backend in the US to dump the 
'recorded' table from the mythconverg database to a file, and transfer that 
file along with the recordings to your EU box.  Then import the data into 
your local (EU) mythconverg database.


> 5) Finally, as I have no need for the LiveTV function, can anyone confirm
> whether the LiveTV functionality is doing anything when I am not running
> the frontend (which I will rarely ever do, but I can do it for
> administration purposes over a Xvnc connection).

LiveTV is only activated if a frontend is using it.

You can get a pretty slick setup going if you setup a Myth frontend for 
yourself.  It will be a little complicated, but feasible.  If you're really 
locked into a Windows box, your best option would be to keep the files in 
MPEG-2 and bite the bullet on the large file transfers.  You can probably 
adjust the capture settings to get the files a little bit smaller.  Your 
other WIndows option is to try to use mythmkmovie to transcode the recordings 
into true MPEG-4 (DivX or Xvid) files that should be playable on a Windows 
box; you'd need to set up a cron job to do this.

Best of luck, and please report back on your progress!

-JAC