MetadataRenderer sometimes does not render metadata with timestamps aligned with DASH period end in multi period streams

[strangesource]

When playing a multi period dash stream where the first period has an EventStream associated that contains an event that is aligned with the period's duration and the next period does not have an EventStream similar to this:

<Period id="0-0-2" start="PT00.000S">
        <BaseURL>...</BaseURL>
        <AdaptationSet id="1" group="1" bitstreamSwitching="true" segmentAlignment="true" contentType="video" mimeType="video/mp4" maxWidth="1920" maxHeight="1080" par="16:9" maxFrameRate="30000/1001" startWithSAP="1">
...
</AdaptionSet>

        <EventStream schemeIdUri="urn:mpeg:dash:event:callback:2015" value="1" timescale="90000">
            <Event presentationTime="3600" duration="90000" id="0" messageData="..."/>
            <Event presentationTime="675000" duration="90000" id="1" messageData="..."/>
            <Event presentationTime="1350000" duration="90000" id="2" messageData="..."/>
            <Event presentationTime="2025000" duration="90000" id="3" messageData="..."/>
            <Event presentationTime="2700000" duration="90000" id="4" messageData="..."/>
        </EventStream>
    </Period>
<Period id="0-0" start="PT30.463S">
....

The event with the id 4 is sometime not surfaced. It is not 100% reliably reproducible with all device, but it does not seem to be device dependent but rather a timing issue. I was e.g. able to reproduce it every time on a Pixel 5 API 29 emulator.

When debugging, the following behaviour can be observed:

On period change in the MetadataRenderer.render function, result is equal to C.RESULT_BUFFER_READ as the stream was set to final (setCurrentStreamFinal) from the maybeUpdateReadingPeriod. This sets inputStreamEnded to false, ultimately disabling the renderer.

At the same time, positionUs is still smaller than the metadata's associated time stamp (and therefore the periods duration), which causes the rendere to not render that metadata.

Tested with ExoPlayer 2.12.0, 2.13.2

• Android 9 & 10 (but should not matter)
• OnePlus 5, Pixel 5 Emulator

[icbaker]

Thanks for the report - can you please provide a manifest we can use to reproduce the issue?

Please either upload it here or send to dev.exoplayer@gmail.com using a subject in the format "Issue #1234" (where "#1234" should be replaced with this issue number.) Please also update this issue to indicate you’ve done this.

[strangesource]

I have send you an e-mail containing a manifest I used to reproduce the mentioned issue.

[icbaker]

Thanks for the manifest - I can reproduce that the message with id=4 isn't logged with an EventLogger, while 0 - 3 are.

I'll dig deeper into what's going on here.

[icbaker]

I worked out MetadataRenderer#isEnded() was returning true too early. It was waiting until it had fully consumed the input, instead of waiting until it had processed and rendered all the data. I've got a change in review that changes this behaviour & ensures that messages near the end of a period are always output.