Re: Low precision on time remap
Re: Low precision on time remap
- Subject: Re: Low precision on time remap
- From: Bruce Sharpe <email@hidden>
- Date: Mon, 16 Feb 2009 19:28:13 -0800
Thanks for the thoughts, Andreas. As for the Zoom, that is precisely
one of the devices that has needed this kind of correction. It seems
to depend on which recording mode is used.
If I understand the situation correctly I don't need to worry about
matching Bezier handles because the speed is constant for the whole
clip.
One remaining limitation of using the timecode entry for this purpose
is that speed changes are limited to the granularity of a video frame.
Using subframeoffset can reduce that a bit, but there can still be
enough residual error that there is noticeable phase distortion when
mixing the sound sources. Being able to specify a fine-grained
percentage would be better, but in the absence of that, modifying the
audio outside FCP (via QT wrapper, perhaps?) is another option.
Bruce
On Mon, Feb 16, 2009 at 3:53 PM, Andreas Kiel <email@hidden> wrote:
> Just my 2 cents on this,
>
> The speed change - which will be okay in most cases - does work fine. You
> should use the timecode entry in the panel instead of the percent entry.
> The XML allows you set up pretty exact the speed changes by keyframe, but
> it's complicated as you have to calculate the Bezier handlers of the
> keyframes In/Out to get a smooth match if you got more than 2 (beginning and
> end). I wouldn't recommend do something like that. Check the actual "off",
> recalc the real time and it works. You also can put the audio into a
> QT-Wrapper file and go from there.
> It's easier and cheaper to get a device which runs a good quartz clock to
> keep the sampling rate. Even my little 200 USD ZOOM does it it for a
> concert.
>
> As said just my 2 cents
> Andreas
>
> On 16.02.2009, at 18:34, Darrin Cardani wrote:
>
>>
>> On Feb 14, 2009, at 11:50 PM, Bruce Sharpe wrote:
>>
>>> I want to overlay clips from recording devices that are free-running
>>> (not jam-synched). Even though most of the clocks are pretty
>>> accurate, these are clips of live events that last a long time and
>>> over the course of many minutes it is not unusual for them to drift
>>> apart from one another by an amount that needs to be corrected. Time
>>> remap seems like a good mechanism to adjust things back into sync.
>>> But the speed value only seems to be able to retain numbers up to a
>>> precision of two decimal places. For example, enter 100.12345 in the
>>> user interface and 100.133 is what gets stored in the XML, which is
>>> not even rounded properly. The residual error over the length of an
>>> hour can be hundreds of milliseconds, which is not acceptable for many
>>> synchronization purposes.
>>>
>>> I can't figure out if this is an artifact of the user interface or
>>> some fundamental limitation. Is there a sneaky way to specify a remap
>>> speed with greater precision?
>>
>>
>> Just curious - what happens if you modify the XML by hand and put in the
>> extra precision digits? Does the app actually use them?
>>
>> Darrin
>> --
>> Darrin Cardani
>> email@hidden
>>
>>
>> _______________________________________________
>> Do not post admin requests to the list. They will be ignored.
>> Pro-apps-dev mailing list (email@hidden)
>> Help/Unsubscribe/Update your Subscription:
>>
>> This email sent to email@hidden
>
>
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Pro-apps-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden