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Re: Audio-ISSUE-105 (MIDI timestamp resolution): timestamps in MIDI should use High Resolution Time [MIDI API]

From: Chris Rogers <crogers@google.com>
Date: Fri, 1 Jun 2012 13:02:09 -0700
Message-ID: <CA+EzO0kotYwF6K1vCf1A1gdVfG4hC1j-wZ9ByS2_9T4HT7AA4A@mail.gmail.com>
To: Jussi Kalliokoski <jussi.kalliokoski@gmail.com>
Cc: Audio Working Group <public-audio@w3.org>
On Fri, Jun 1, 2012 at 8:22 AM, Jussi Kalliokoski <
jussi.kalliokoski@gmail.com> wrote:

> Good catch, thank you! As I planned it, the timestamp should have been a
> floating point value, allowing for sub-millisecond precision, but actually
> DOMHighResTimeStamp is actually more fit fore this.
> I will make the necessary changes to the spec.
>

I agree that we should support sub-millisecond precision and think we
should use DOMHighResTimeStamp.

Chris


> Cheers,
> Jussi
>
>
> On Fri, Jun 1, 2012 at 6:16 PM, Audio Working Group Issue Tracker <
> sysbot+tracker@w3.org> wrote:
>
>> Audio-ISSUE-105 (MIDI timestamp resolution): timestamps in MIDI should
>> use High Resolution Time [MIDI API]
>>
>> http://www.w3.org/2011/audio/track/issues/105
>>
>> Raised by: Adam Goode
>> On product: MIDI API
>>
>> The current MIDI API specifies timestamp as a long representing
>> "milliseconds from the UNIX Epoch".
>>
>> For MIDI applications, millisecond resolution is insufficient and can
>> cause noticeable jitter.
>>
>> Using absolute wallclock time is also problematic, as it is subject to
>> system clock skew.
>>
>> The MIDI timestamp should use High Resolution Time (DOMHighResTimeStamp),
>> which solves these problems:
>>
>> http://dvcs.w3.org/hg/webperf/raw-file/tip/specs/HighResolutionTime/Overview.html
>>
>>
>>
>>
>
Received on Friday, 1 June 2012 20:02:38 GMT

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