Only one clip added to track when they have the same duration

[stephanedebove]

Following up on an issue I originally posted here.

[x ] Incorrect Functionality or bug

Description

I’m using a python script to generate a timeline exported to an xml file. I think I’ve encountered a bug: when I add two clips of the same duration on the same track on my timeline, only one of them is added to my xml file. For instance, this timeline is exported correctly, with two distinct <clipitem> generated in the xml:

Timeline(
    "TimeLine1", 
    Stack(
        tracks, [
            otio.schema.Track(
                name='Video track 1', 
                children=[
                    otio.schema.Clip(
                        name='file.mp4', 
                        media_reference=otio.schema.ExternalReference(
                            target_url='C:\\file.mp4'
                        ), 
                        source_range=otio.opentime.TimeRange(
                            start_time=otio.opentime.RationalTime(value=0, rate=25), 
                            duration=otio.opentime.RationalTime(value=50, rate=25)
                        ), 
                        metadata={}
                    ), 
                    otio.schema.Clip(
                        name='file.mp4', 
                        media_reference=otio.schema.ExternalReference(
                            target_url='C:\\file.mp4'
                        ), 
                        source_range=otio.opentime.TimeRange(
                            start_time=otio.opentime.RationalTime(value=0, rate=25), 
                            duration=otio.opentime.RationalTime(value=75, rate=25)
                        ), 
                        metadata={}
                    )
                ], 
                source_range=None, 
                metadata={}
            )
        ], 
        None, 
        {}
    )
)

(notice both clips have a different duration)

But this timeline is NOT exported correctly, I get only one <clipitem> in my xml file (the behavior I’m expecting is two clips of the same duration following each other on video track 1. Both clips are made from the same file):

Timeline(
    "TimeLine1", 
    Stack(
        tracks, [
            otio.schema.Track(
                name='Video track 1', 
                children=[
                    otio.schema.Clip(
                        name='file.mp4', 
                        media_reference=otio.schema.ExternalReference(
                            target_url='C:\\file.mp4'
                        ), 
                        source_range=otio.opentime.TimeRange(
                            start_time=otio.opentime.RationalTime(value=0, rate=25), 
                            duration=otio.opentime.RationalTime(value=50, rate=25)
                        ), 
                        metadata={}
                    ), 
                    otio.schema.Clip(
                        name='file.mp4', 
                        media_reference=otio.schema.ExternalReference(
                            target_url='C:\\file.mp4'
                        ), 
                        source_range=otio.opentime.TimeRange(
                            start_time=otio.opentime.RationalTime(value=0, rate=25), 
                            duration=otio.opentime.RationalTime(value=50, rate=25)
                        ), 
                        metadata={}
                    )
                ], 
                source_range=None, 
                metadata={}
            )
        ], 
        None, 
        {}
    )
)

I simply export the timeline with

otio.adapters.write_to_file(timeline, file.xml)

Optional

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Environment

Operating System: Windows
Python version if appropriate: 3.10.14
OpentimelineIO version: opentimelineio-0.17.0 (but I was having the same problem with 0.16)