Injecting clock based TC at first frame captured

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Injecting clock based TC at first frame captured

Steinar Apalnes
Hi,

I'm doing a lot of capturing through decklink video devices and I was
wondering if it was, or would be possible to make ffmpeg set a frame
accurate start TC based on wall clock when the first frame was captured?
An option like this maybe:

-tc_inject 1

Where 1 could be the first frame.

or

-tc_inject now
-timecode now

Maybe this kind of option exist or maybe there are other good ways of
solving the "problem" but I have yet to find a solution.

Thanks!

Steinar Apalnes
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Re: Injecting clock based TC at first frame captured

Dave Rice-3

> On Jun 4, 2018, at 4:41 PM, Steinar Apalnes <[hidden email]> wrote:
>
> Hi,
>
> I'm doing a lot of capturing through decklink video devices and I was
> wondering if it was, or would be possible to make ffmpeg set a frame
> accurate start TC based on wall clock when the first frame was captured?
> An option like this maybe:
>
> -tc_inject 1
>
> Where 1 could be the first frame.
>
> or
>
> -tc_inject now
> -timecode now
>
> Maybe this kind of option exist or maybe there are other good ways of
> solving the "problem" but I have yet to find a solution.

There is a patch regarding this under consideration on ffmpeg-devel. See http://ffmpeg.org/pipermail/ffmpeg-devel/2018-May/230500.html or subject line "[FFmpeg-devel] [PATCH] Limited timecode support for lavd/decklink".
Best Regards,
Dave Rice

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Re: Injecting clock based TC at first frame captured

Steinar Apalnes
Thanks for the reply! :-)

My request/question is not strictly related to decklink but capturing in
general; The ability to set the start tc when the first frame is captured
from any capture device. The method should not be depending on incoming tc
signals from external devices but rather rely on the PC clock to determine
the "exact" capture time of the first frame. If it's feasable.

-steinar

2018-06-05 21:47 GMT+02:00 Dave Rice <[hidden email]>:

>
> > On Jun 4, 2018, at 4:41 PM, Steinar Apalnes <[hidden email]> wrote:
> >
> > Hi,
> >
> > I'm doing a lot of capturing through decklink video devices and I was
> > wondering if it was, or would be possible to make ffmpeg set a frame
> > accurate start TC based on wall clock when the first frame was captured?
> > An option like this maybe:
> >
> > -tc_inject 1
> >
> > Where 1 could be the first frame.
> >
> > or
> >
> > -tc_inject now
> > -timecode now
> >
> > Maybe this kind of option exist or maybe there are other good ways of
> > solving the "problem" but I have yet to find a solution.
>
> There is a patch regarding this under consideration on ffmpeg-devel. See
> http://ffmpeg.org/pipermail/ffmpeg-devel/2018-May/230500.html or subject
> line "[FFmpeg-devel] [PATCH] Limited timecode support for lavd/decklink".
> Best Regards,
> Dave Rice
>
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> [hidden email] with subject "unsubscribe".
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Re: Injecting clock based TC at first frame captured

Dave Rice-3

> On Jun 5, 2018, at 4:12 PM, Steinar Apalnes <[hidden email]> wrote:
>
> Thanks for the reply! :-)
>
> My request/question is not strictly related to decklink but capturing in
> general; The ability to set the start tc when the first frame is captured
> from any capture device. The method should not be depending on incoming tc
> signals from external devices but rather rely on the PC clock to determine
> the "exact" capture time of the first frame. If it's feasable.

Perhaps add something like:
-metadata "timecode=$(date +"%T:00")"

> -steinar
>
> 2018-06-05 21:47 GMT+02:00 Dave Rice <[hidden email]>:
>
>>
>>> On Jun 4, 2018, at 4:41 PM, Steinar Apalnes <[hidden email]> wrote:
>>>
>>> Hi,
>>>
>>> I'm doing a lot of capturing through decklink video devices and I was
>>> wondering if it was, or would be possible to make ffmpeg set a frame
>>> accurate start TC based on wall clock when the first frame was captured?
>>> An option like this maybe:
>>>
>>> -tc_inject 1
>>>
>>> Where 1 could be the first frame.
>>>
>>> or
>>>
>>> -tc_inject now
>>> -timecode now
>>>
>>> Maybe this kind of option exist or maybe there are other good ways of
>>> solving the "problem" but I have yet to find a solution.
>>
>> There is a patch regarding this under consideration on ffmpeg-devel. See
>> http://ffmpeg.org/pipermail/ffmpeg-devel/2018-May/230500.html or subject
>> line "[FFmpeg-devel] [PATCH] Limited timecode support for lavd/decklink".
>> Best Regards,
>> Dave Rice
>>
>> _______________________________________________
>> ffmpeg-user mailing list
>> [hidden email]
>> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>>
>> To unsubscribe, visit link above, or email
>> [hidden email] with subject "unsubscribe".
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> [hidden email] with subject "unsubscribe".

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Re: Injecting clock based TC at first frame captured

Steinar Apalnes
I does not work. Besides, what would ":00" do? The TC need to be as
frame-accurate as possible, so we need to convert millisecond of the first
captured frame to frame. F.ex: 10:45:13:21 where 21 would be
(approximately) 840 ms after 10:45:13 at 25 fps.

-steinar

2018-06-06 17:43 GMT+02:00 Dave Rice <[hidden email]>:

>
> > On Jun 5, 2018, at 4:12 PM, Steinar Apalnes <[hidden email]> wrote:
> >
> > Thanks for the reply! :-)
> >
> > My request/question is not strictly related to decklink but capturing in
> > general; The ability to set the start tc when the first frame is captured
> > from any capture device. The method should not be depending on incoming
> tc
> > signals from external devices but rather rely on the PC clock to
> determine
> > the "exact" capture time of the first frame. If it's feasable.
>
> Perhaps add something like:
> -metadata "timecode=$(date +"%T:00")"
>
> > -steinar
> >
> > 2018-06-05 21:47 GMT+02:00 Dave Rice <[hidden email]>:
> >
> >>
> >>> On Jun 4, 2018, at 4:41 PM, Steinar Apalnes <[hidden email]> wrote:
> >>>
> >>> Hi,
> >>>
> >>> I'm doing a lot of capturing through decklink video devices and I was
> >>> wondering if it was, or would be possible to make ffmpeg set a frame
> >>> accurate start TC based on wall clock when the first frame was
> captured?
> >>> An option like this maybe:
> >>>
> >>> -tc_inject 1
> >>>
> >>> Where 1 could be the first frame.
> >>>
> >>> or
> >>>
> >>> -tc_inject now
> >>> -timecode now
> >>>
> >>> Maybe this kind of option exist or maybe there are other good ways of
> >>> solving the "problem" but I have yet to find a solution.
> >>
> >> There is a patch regarding this under consideration on ffmpeg-devel. See
> >> http://ffmpeg.org/pipermail/ffmpeg-devel/2018-May/230500.html or
> subject
> >> line "[FFmpeg-devel] [PATCH] Limited timecode support for
> lavd/decklink".
> >> Best Regards,
> >> Dave Rice
> >>
> >> _______________________________________________
> >> ffmpeg-user mailing list
> >> [hidden email]
> >> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >>
> >> To unsubscribe, visit link above, or email
> >> [hidden email] with subject "unsubscribe".
> > _______________________________________________
> > ffmpeg-user mailing list
> > [hidden email]
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >
> > To unsubscribe, visit link above, or email
> > [hidden email] with subject "unsubscribe".
>
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> [hidden email] with subject "unsubscribe".
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