[mythtv-users] Back-toBack recordings from the same source

[Nick Rout]

On Wed, Apr 25, 2012 at 10:58 AM, Pieter De Wit <pieter at insync.za.net> wrote:
> Hello List,
>
> This might be a dev list question, but here goes:
>
> Is there a way to tell Mythtv to use the same source for back-to-back
> recordings of programs, with overlapping start and finish times ? (what a
> mouth full :) )
>
> Let see how my ASCII art skills are:
>
>
> ------>time
>
> --->(1)--->(2)--->(3)-->(4)--->(5)--->
>
> 1) Start of "P1" recording
> 2) Real start of "P1"
> 3) Start of "P2" recording
> 4) End of "P1"/Start of "P2" following 1 or two ads (In New Zealand, zero
> ads between programs on some channels, there is title scrolling and all
> that)
> 5) End of "P1" recording
> --> Live goes on
>
> I have found it *very* hard to get the over-recording right (I think they
> call it "island time" :D ). The best way for me is to set the pre-start
> recording time to 120 seconds and over record by 300 seconds. The problem
> this causes is that "all" my tuners are busy (hauppauge Nova S Plus)
>
> I am told this card can do up to 8 recordings (via that magic that Myth
> does) but I could have sworn the last time I set it to 8 the quality went
> down (the picture appeared snowy) If the card is happy to handle 8 decodes,
> then that solves my problem, but what about people that arn't that lucky.
>
> Here is what I thought could happen:
>
> At 3) - create another ring buffer that "feeds off" the already created ring
> buffer for 1)
> At 4) - release the ring buffer for 1)
> At 5) - release the ring buffer created at 3)
>
> I hope that makes sense, comments/flaming welcome
>

That method has been suggested but not implemented. I am sure you will
get the "patches welcome" response :)

Your DVB card does not decode. It pushes data to the hard drive. The
constraints are IO (including PIC/PCIe speeds and Disk IO).