[mythtv-users] PVR-350 won't record without reboot

Michael T. Dean mtdean at thirdcontact.com
Sun Nov 22 05:40:04 UTC 2009

On 11/21/2009 10:25 PM, f-myth-users at media.mit.edu wrote:
>     > Date: Sat, 21 Nov 2009 20:59:20 -0500
>     > From: "Michael T. Dean" <mtdean at thirdcontact.com>
>     > And note that MythTV trunk can still use the PVR-350 TV out with the 
>     > ivtvfb module and Xv video output.  So, all you lose on the PVR-350 is 
> ...although I think this was broken in a recent X and fixed last week;
> there was traffic on the ivtv list recently that I can look up and
> point to if anyone needs to know.  But it may be an issue with the
> latency with which it works its way through various distros release
> pipelines, etc.

Good info.  That may be  important for anyone who is still using the 
PVR-350 TV out.  Thanks.

>     > the anachronistic 480i60 (576i50 for PAL) MPEG-2 decoder--where even toy 
>     > CPU's can decode standard definition MPEG-2 at 50/60 fields per second 
>     > without breaking a sweat.  It's not 1999, anymore.  :)
> You also lose the ability to let the TV decode the closed captions
> itself from things you recorded on PVR-x50 tuners, and must instead
> rely on Myth being able to extract the captions from the source and
> then superimpose them back on the screen using its internal player.  I
> get the feeling that handling captions is a perennial afterthought for
> most people, and I've seen various complaints about them being broken
> in various ways at various times in Myth, but I'm not sure about their
> current status

I can say that I can't remember the last show I watched without 
captions--other than ones where the network breaks/messes up the 
captions to the point they're not useful.  (To the point that I actually 
recognize the work of captioning organizations that do the best/worst 
jobs with captions in the shows I watch.)  If they stopped working for 
me, I'd notice.

Sure, I would love to do some work on improving the EIA-708 caption 
support in Myth, but I haven't gotten around to it since the EIA-608 
captions work fine.

And, yes, I'm only testing the EIA-608/EIA-708 captions in my ATSC 
recordings, but I haven't used a PVR-x50 for 3 years, now, so it's hard 
for me to test those on a frequent basis.  I'd guess, though, that in 
today's US (where the transition to digital OTA has been made), since 
the users of PVR-350's would be using some other receiver (such as a 
cable- or satellite-STB), any breakage of captions is more likely due to 
problems with the STB's output of them than problems with Myth's ability 
to use them.  (Or, potentially, for some PVR-x50's/500's, problems with 
ivtv drivers--though I don't know the status of that one, some have 
mentioned there may be issues with some cards/drivers.)

> ---because when I want closed captions, I tell my TV to
> display them from what the 350 is feeding it...  [It also means you
> must find somewhere on your remote to bind the relevant key so that
> you can tell Myth enable/disable captioning, instead of using the
> remote for the TV itself.  This can be a problem if you're already
> short of buttons on the remote that Myth is listening to.]

Well, LIRC modes can help with that--or, for that matter, just 
programming the TV remote to work with LIRC, too, and intercepting the 
closed-caption button.  :)

> (If the various nVidia cards that do VDPAU have the ability to feed
> such captioning directly to the TV on line 21 when using their S-Video
> outputs, I've sure never heard of it.)
> This is something I'm going to be tripping over firsthand once I go
> to 0.22 and a VDPAU card; I'd like to take NTSC SD video, transcode to
> H.264 to save space, and then play it back on a VDPAU card.  How well
> are people finding closed-captioning is doing when thrown into this
> mix?  Any advice?

I can tell you that all of Myth's transcoding--save lossless MPEG-2 
transcodes--will strip out any captions/subtitles (and even the lossless 
can mess them up a bit, especially around cuts).  My best suggestion 
would be to get a new 1TB to 2TB HDD or more...  (That's a serious 
suggestion.  IMHO, the energy cost of transcoding isn't worth the space 
saved--in some cases is greater than the cost of the space saved.  The 
latter being especially true when using older/smaller hard drives (or 
worse, multiple older, smaller hard drives) that could be replaced with 
larger/newer/more energy-efficient ones.)

> Similarly, I believe you also lose wss support (e.g., the mode that
> allows TV's like the Sony WEGA to go to a resolution-preserving 16:9
> format by packing all of its lines into a smaller vertical slice of
> the screen), although this was uncommon to see in broadcast sources.

Though I don't know the state of WSS support in ivtv-recordings done by 
Myth and played back through the PVR-350's decoder, I can tell you that 
the zoom/fill modes in Myth work great.  And 0.22 has automatic 
letterbox detection support, too (as long as you're not using VDPAU and 
possibly some other hardware renderers).

> (It -was- common to see in DVD sources

And Myth will actually use the aspect ratio specified by the digital 
source (DVD or digital TV).

Still, though, since no one who actually uses the PVR-350 decoder has 
stepped up to maintain the code, and since the functionality being lost 
isn't really that important, anymore, and other use cases can achieve 
similar functionality, the amount of code cleanup we get by removing it 
is seriously beneficial.  See http://svn.mythtv.org/trac/changeset/22845 
and note that the 4 files that were deleted (those with red boxes by the 
filenames) are not shown in the modifications there, and account for 
another 2250 lines of source code removed.


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