Ad plays properly on HTML but improperly on Mobile

[Cole C]

Hello, 

I have an audio only pre-roll VAST ad that I have verified works on the Google IMA SDK tester

Here is the ad tag: https://od-spy.live.streamtheworld.com/ondemand/ars?type=preroll
Here is the tester link

On mobile (ios simulator iphone 15 pro, Google IMA SDK) the ad plays, however the elapsed timer is stuck at "0:00", and all of the impressions STARTED,FIRST_QUARTILE,MIDPOINT,THIRD_QUARTILE fire immediately. 
I also see in the console 

Core: (INFO) ima.admanager.VideoAdManager: Playback error: AdError 202: VAST media file duration differs from the VAST response duration by 29.70 seconds.
Core: Exception text: AdError 202: VAST media file duration differs from the VAST response duration by 29.70 seconds.

However this is incorrect. 

I am using the BasicExample in the sample Github repo, and only changed the `adTagURLString = https://od-spy.live.streamtheworld.com/ondemand/ars?stid=93553&type=preroll&ad_type=audio` to play my own ad. 

I can play other audio ads successfully, such as `https://www.radiantmediaplayer.com/vast/tags/audio.xml`

I am at my wit's end trying to debug this. What is incorrect with the provided BasicExample implementation? 

[IMA SDK]

Hi,

Thank you for contacting IMA SDK Support Team.

I have raised this concern to the wider team and will get back to once i get any update on this. Meanwhile, your patience is important.
 

This message is in relation to case "ref:!00D1U01174p.!5004Q02vGh7g:ref" (ADR-00273682)

Thanks,
 

IMA SDK Team

[Cole C]

Hello IMA-SDK team, it's been a few weeks. Do you have any updates? 

Thanks,

Cole

[IMA SDK]

Hi Cole,

We do not currently have an update regarding this matter. We will inform you as soon as we receive any updates. In the meantime, we appreciate your patience.

[IMA SDK]

Hi Cole,

I've checked your shared VAST and found that 'Content-Range' response header is missing in your mp3 file as iOS uses byte range to determine duration.
Could you configure your mp3 asset to return 'Content-Range' response header or replace your asset file with another mp3 which contain 'Content-Range' response header'.

Thanks

[Cole C]

Hey, 

Thanks for getting back to me. Unfortunately I do not have access to the files as it's being served by a third party. 

Is there any way I could utilize the IMA SDK to be able to handle this audio? The ad loads and plays fine, is there some way I can override the content duration that leads to the impression events firing? 

Thanks,

Cole

[IMA SDK]

Hi Cole,

There is no other way to modify the audio file response header or adding contentDuration on run time through IMA SDK.
I would suggest to contact to your third party and raise this concern.

Thanks
 

This message is in relation to case "ref:!00D1U01174p.!5004Q02vGh7g:ref" (ADR-00273682)

Thanks,
 

IMA SDK Team

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[IMA SDK]

Hi Cole,

Are you still facing this issue or found a workaround of it ? Kindly update.

[IMA SDK]

Hi Cole,

I will inform this to the team and I will follow up here as soon as I have an update to share.

[Cole C]

Hey, 

I unfortunately did not find a workaround. The client was not able to adjust their response headers, so I had to build my own vast ad audio player with impression tracking from scratch. 

It was quite tedious and I'd love to be able to use the IMA SDK! I wish the SDK had a workaround for this. 

Thanks,

Cole

[IMA SDK]

Hi,

It doesn't seem worth re-architecting our code to fall back to VAST duration just to potentially fix it (and ultimately it seems to be a limitation of AVPlayer rather than IMA).

Thanks,
 

IMA SDK Team

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[2025-08-13 19:07:53Z GMT] This message is in relation to case "ref:!00D1U01174p.!5004Q02vGh7g:ref" (ADR-00273682)