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negative TC in time

Igor Riđanović
 

Hello everyone. I'm doing some small steps exploring OTIO as my time allows.

Why is the timeline timecode in point represented as a negative integer?

For example, I have a single event EDL called "short.edl":

TITLE: short
FCM 23.98
001  001      V     C        01:00:00:00 01:00:23:00 02:00:00:00 02:00:23:00
* some metadata

And this script:

import opentimelineio as otio

timeline = otio.adapters.read_from_file('short.edl')
otio.adapters.write_to_file(timeline, 'converted.otio')

The 02:00:00:00 timecode in the record column is represented as -172800 in the converted.otio JSON file:

"start_time": {
                        "OTIO_SCHEMA": "RationalTime.1",
                        "rate": 24.0,
                        "value": -172800
                    }



--
Igor Riđanović

213.293.8230 Los Angeles
hdhead.com  metafide.com
Joshua Minor
 

EDLs often start at some time other than 00:00:00:00, like one hour. In your example, that looks like 2 hours. I believe that the EDL adapter has not yet been updated to use the global_start_time attribute on Timeline and instead uses this negative offset to preserve this offset in the record time of the track.

---
Joshua Minor (he-him)
Pixar Studio Tools Story/Editorial/VR Previs Tech Lead
joshm@...

On Sep 3, 2019, at 6:55 PM, Igor Riđanović <igor@...> wrote:

Hello everyone. I'm doing some small steps exploring OTIO as my time allows.

Why is the timeline timecode in point represented as a negative integer?

For example, I have a single event EDL called "short.edl":

TITLE: short
FCM 23.98
001  001      V     C        01:00:00:00 01:00:23:00 02:00:00:00 02:00:23:00
* some metadata

And this script:

import opentimelineio as otio

timeline = otio.adapters.read_from_file('short.edl')
otio.adapters.write_to_file(timeline, 'converted.otio')

The 02:00:00:00 timecode in the record column is represented as -172800 in the converted.otio JSON file:

"start_time": {
                        "OTIO_SCHEMA": "RationalTime.1",
                        "rate": 24.0,
                        "value": -172800
                    }



--
Igor Riđanović

213.293.8230 Los Angeles
hdhead.com  metafide.com
Igor Riđanović
 

Thanks. It seems that the "-" sign is superfluous. If I remove it in the *.otio file and generate an EDL the event record in time is still 02:00:00:00.


Igor Riđanović

213.293.8230 Los Angeles
hdhead.com  metafide.com

On 9/4/19 3:42 PM, Joshua Minor wrote:

EDLs often start at some time other than 00:00:00:00, like one hour. In your example, that looks like 2 hours. I believe that the EDL adapter has not yet been updated to use the global_start_time attribute on Timeline and instead uses this negative offset to preserve this offset in the record time of the track.

---
Joshua Minor (he-him)
Pixar Studio Tools Story/Editorial/VR Previs Tech Lead
joshm@...

On Sep 3, 2019, at 6:55 PM, Igor Riđanović <igor@...> wrote:

Hello everyone. I'm doing some small steps exploring OTIO as my time allows.

Why is the timeline timecode in point represented as a negative integer?

For example, I have a single event EDL called "short.edl":

TITLE: short
FCM 23.98
001  001      V     C        01:00:00:00 01:00:23:00 02:00:00:00 02:00:23:00
* some metadata

And this script:

import opentimelineio as otio

timeline = otio.adapters.read_from_file('short.edl')
otio.adapters.write_to_file(timeline, 'converted.otio')

The 02:00:00:00 timecode in the record column is represented as -172800 in the converted.otio JSON file:

"start_time": {
                        "OTIO_SCHEMA": "RationalTime.1",
                        "rate": 24.0,
                        "value": -172800
                    }



--
Igor Riđanović

213.293.8230 Los Angeles
hdhead.com  metafide.com

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