[mythtv-users] An option for watching tv

Brad DerManouelian myth at dermanouelian.com
Fri Dec 1 17:23:52 UTC 2006

On Dec 1, 2006, at 9:08 AM, Jeff Wormsley wrote:

> Brad DerManouelian wrote:
>> Maybe you should replace your wife and see if that solves your slow
>> channel-change issues.
> That, sir, was uncalled for, and you know it.

Oh, for goodness sake. It was a joke, and you know it.

>> No one has said there is no problem. Just that there is no problem
>> for them. The work-arounds are acceptable to most people. And quite
>> frankly, changing channels on my DirecTivo took just about as long as
>> it does with MythTV, so I've just come to accept the fact that
>> changing channels takes that long. MT Cox Digital box took longer to
>> change channels than MythTV with a DirecTV D-11 STB.
> MythTV is my first PVR, and a first for my wife as well.  Comparing  
> to a
> DirecTivo isn't of any use to me.  As far as I know, DirecTivo was a
> piece of crap.  It must have been, you dropped it in favor of MythTV,
> didn't you?  (See, if you want to trade insults, I can play that game,
> but I'd suggest taking that portion of the conversation off list.)

The point was that lots of digital video systems share this  
limitation. If the problem was so easily remedied, none of them would  
have it. I don't take what you said as an insult. You don't appear to  
be very good at that game.

> What I do know is this:
> a) Changing channels with the ivtv utilities on a PVR-250 while
> displaying video with MPlayer is near enough to instant as to make no
> difference.  This says that there is nothing in the capture, playback,
> or channel change process that takes any significant amount of time.
> This leaves the buffering process as the only possible source for slow
> channel change times.

MythTV is not just changing a channel. If it was, it would be instant  
(to you, not in the Einstein sense of instantaneous).

> b) Buffering video to a file on Linux, and reading back that buffer  
> on a
> modern processor should not take 3 to 10 seconds to accomplish on a
> combined FE/BE.  Maybe it would over the network for a split  
> system, but
> with a 100BaseT network, even that is a stretch.  The amount of data
> isn't that large, and the bandwidth of the IDE channel, even if poorly
> tuned, certainly isn't that low.  Writing ten frames or so of video to
> provide a buffer, then reading them back again to start playback,  
> should
> be well under a second on a local machine, and probably via a  
> network as
> well.  So somewhere in this process, either many more than ten  
> frames of
> video is being written, or something else is eating up a lot of time.
> If it is more video, then someone who knows the code (read: a dev)
> should be able to find where this amount is specified, lower it,
> recompile and test to see if channel changes are indeed faster.  Your
> average non-programmer can't do this.  Many of us get our Myth systems
> from a repository such as ATRPMS and can't do this.  I don't run SVN
> either, and won't have time to make this check until at least after  
> the
> holidays.

I believe the buffering is preventing your machine from locking up  
(as was recently discussed) due to partial frames on a library that  
Myth developers have no control over. If you'd like to take the issue  
up with the dev team that works on that library, that would be  
helpful to everyone.

>> This is not a public soap box. Someone pays for the bandwidth to
>> communicate. That someone has made his opinion on this subject clear
>> that he does not want to "live with" topics coming up over and over
>> again with the same complaints and no one offering solutions.
> I've only responded to this thread for the first time today, and I
> avoided the previous thread that spawned this one entirely.  If a
> legitimate concern for a non-trivial number of users is off topic,  
> then
> many more threads than this should be cut short as well.

That's the point. It's of no concern to anyone who generously donates  
their time to contribute code to the project - most importantly, Isaac.

> --
> I haven't smoked for 3 months, 2 weeks and 12 hours,
> saving $479.54 and not smoking 3,196.94 cigarettes.
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