[mythtv] DVD playback AV sync issues: all solved (?)

[Taylor Ralph]

On Fri, Feb 5, 2010 at 2:35 AM, Davin McCall <davmac at davmac.org> wrote:
> On 05/02/10 16:52, Taylor Ralph wrote:
>>
>> I just found one issue so far. You've got the m_can_double comparison
>> backwards which causes 2x deinterlacing to be disabled.
>>
>>
>
> Hmm
>
>            m_can_double = (frame_interval / 2 >
> videosync->getRefreshInterval() * 1.005);
>
> My head might not be screwed on right today, but: I don't think this is
> backwards ... it's checking the frame interval when halved is greater than
> the refresh interval. Or in other words, the frame rate when doubled is
> lower than the refresh rate.
>
> Davin

Err, it was the tolerance put on the wrong side. That's what caused my
29.97i recordings to not be deinterlaced on my 60 fps display.

Since (1/29.97)/2 < 1/60 * 1.005 which calculates to 16.68 < 16.75
which causes m_can_double to be false.

So you actually have the tolerance on the wrong side.

So it should be

    int tolerance = getRefreshInterval() * 1.005;
    m_can_double = ((frame_interval / 2) + tolerance) >
videosync->getRefreshInterval();

which should make it equivalent to the prior code. The tolerance
should ease the requirement not make it more demanding.

Regards.

--
Taylor