Re: [LAD] transport/timebase calculations

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To: Linux Audio Developers <linux-audio-dev@...>
Date: Sunday, July 11, 2010 - 8:10 pm

>> Now, for your rolling transport counter code...

I've been looking back over at those source codes...

Using a low ppqn such as 24 in my timebase code (based on
non-sequencer) utterly fails. Using a ppqn of 100 in non-sequencer
fails too. As does using a low ppqn in Dino.

(I see you've used a low ppqn of 48 in Tritium/Composite, and are
using jack_position_t::bbt_offset)

In other words, you're right about it sticking when nframes <
frames_per_tick and needing bbt_offset. Until now I did not realize
this is worked-around by using a high ppqn such as 1920 or 2520 (which
give integer results when divided by integers up to values 8 and 9
respectively (ie what the magic number means)).

So with low ppqn values, the bbt_offset integer will be ok, but what
about for high ppqn values?

Even high ppqn won't be perfect, but might not a floating point
bbt_offset improve the timing?*

*not in my case, it's some more serious problem in my code.

Cheers,
James.

>> [1]

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Messages in current thread:
[LAD] transport/timebase calculations, James Morris, (Sun Jul 11, 1:27 pm)
Re: [LAD] transport/timebase calculations, Gabriel M. Beddingfield, (Sun Jul 11, 3:02 pm)
Re: [LAD] transport/timebase calculations, James Morris, (Sun Jul 11, 6:29 pm)
Re: [LAD] transport/timebase calculations, James Morris, (Sun Jul 11, 8:10 pm)
Re: [LAD] transport/timebase calculations, Gabriel M. Beddingfield, (Sun Jul 11, 10:10 pm)
Re: [LAD] transport/timebase calculations, James Morris, (Sun Jul 11, 10:59 pm)