[Jack-Devel] How to use the BBT position information

Philipp Müller thetruephil at googlemail.com
Tue Dec 4 16:04:16 CET 2018

On 12/4/18 2:40 PM, Chris Caudle wrote:
> On Tue, December 4, 2018 5:00 am, Philipp Müller wrote:
>> don't...want to introduce new bugs while attempting to fix the JACK
>> audio driver.
> Maybe start with which jack audio driver, and what exactly you think needs
> to be fixed.
I'm talking about the JACK audio driver of Hydrogen [1]. Whenever there
is a JACK timebase master, which is not Hydrogen itself, the callback
function relocates its internal transport position in frames to the one
calculated from the beat, bar, and tick information. But since this
position corresponds to the one of the last tick passed, it usually does
not match the current transport position of the JACK server. This will
be noticed by the program, which prints a warning [2].

To resolve this issue I want to remove the relocation according to the
BBT information and instead just handle the tempo change via the
JackPositionBBT info properly. But I'm not quite sure whether I might
miss some use cases this relocation by the BBT would be necessary.


[1] https://github.com/hydrogen-music/hydrogen

[2] https://github.com/hydrogen-music/hydrogen/issues/602

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