[mythtv-users] Re: mpeg 2 playback glitches

[Russ Southern]

On Thu, Jul 24, 2003 at 05:36:28PM -0700, Steven J. Finnegan wrote:
> What did you have to change to get two-PVR-250's to work?
> (I have a PVR-250 and a PVR-350 in the same backend.

Actually, the only change I have made was to significantly increase a
buffer size and number of mpg_buffers in ivtv.  

    Note: don't increase the buffer size.  The ivtv developers say it will
    crash when capturing raw video if the size is changed.  I only capture
    mpeg, so I don't care, but ymmv.  To be safe, just increase your number
    of buffers using the instructions below.  If you still want to mess with
    dma_buffer_size, look in ivtv.h for "#define IVTV_DMA_BUF_SIZE".  The
    comment shows two values.  Change to the bigger number, recompile,
    install.

I increased the maximum number of buffers (it's just a check at load time)
available.  You can have up to 100 by default (you add an option in
modules.conf):

options ivtv mpg_buffers=100

but with two cards I needed more to prevent the "Not enough free buffers"
messages.  Look for this line in ivtv-driver.c:

        if ((mpg_buffers > 100) || (mpg_buffers < 15)) {

and change the 100 to a bigger number.  Recompile and install.  Then change
modules.conf to use the new number.  I suspect 128 would be enough, but
again, ymmv.

----

Now, if I can just get someone to answer how to set options on the card(s)
at capture time (in myth), I'll be totally set (how do I set hue,
brightness, contrast, etc. on the card before each capture?).  

Enjoy!

Russ