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VAST bandwidth detection?

Hi JW Player Team,

we're currently testing a case with a VAST file, which contains multiple MP4 files with different bandwidths and dimensions (see simplified example below). Regarding the logic behind determining the videofile that JW Player will use, I have 2 questions:

1.
Does the JW Player do any kind of bandwidth detection at all? In our tests it seems that it's always the first videofile in the list of matching width/height values that is being played. That means with the example order below (starting with low bitrate, then getting higher) we're always seeing the lowest bitrate - but we'd love to show users the best quality possible.
Do we have any other chance to solve this, besides reordering the files in the VAST XML? What happens if some ad providers don't support reordering and just "send them as they come" (as in our example below) - are we stuck with playing the lowest quality ad then, or can you provide a solution for this case?

2.
Does the JW Player check for player size changes (like switching from a tiny player to fullscreen mode) and then adapt the videofile from the VAST accordingly? At the moment, this doesn't seem to be the case - i.e. when playing in a small player like 400x300 & then going to fullscreen, we still see the small-sized ad videofile.
Also, is there any way to influence the threshold at which videofiles with bigger dimensions are chosen? Right now it seems a file only applies when player size is "equal or higher" than the video dimensions provided inside the VAST. However it would be great to show bigger resolutions already for users with "slightly smaller players", and then just downscale a bit (=better viewing experience than a lot of upscaling).



Here's the simplified VAST <MediaFiles> list excerpt I was referencing in my questions:

<MediaFiles>
<MediaFile delivery="progressive" bitrate="250" width="424" height="320" type="video/mp4" scalable="true" maintainAspectRatio="true">
<![CDATA[http://somevideoserver.com/small_LQ.mp4]]>
</MediaFile>
<MediaFile delivery="progressive" bitrate="400" width="424" height="320" type="video/mp4" scalable="true" maintainAspectRatio="true">
<![CDATA[http://somevideoserver.com/small_HQ.mp4]]>
</MediaFile>
<MediaFile delivery="progressive" bitrate="400" width="640" height="360" type="video/mp4" scalable="true" maintainAspectRatio="true">
<![CDATA[http://somevideoserver.com/640x360_H264_LQ.mp4]]>
</MediaFile>
<MediaFile delivery="progressive" bitrate="800" width="640" height="360" type="video/mp4" scalable="true" maintainAspectRatio="true">
<![CDATA[http://somevideoserver.com/640x360_H264.mp4]]>
</MediaFile>
<MediaFile delivery="progressive" bitrate="1200" width="640" height="360" type="video/mp4" scalable="true" maintainAspectRatio="true">
<![CDATA[http://somevideoserver.com/640x360_H264_HQ.mp4]]>
</MediaFile>
</MediaFiles>



We'd love some clarification on the behaviour of VAST videofile determination & any means to influence it.

Thanks,
Daniel

3 Community Answers

Up Down

Todd

JW Player Support Agent  
0 rated :

I believe our heuristics consider the current width of the player when selecting the appropriate ad creative. Because your ad tag lists the lower quality version first, I would not be surprised if we are using the first appropriate width we find.

From the <MediaFiles> example you give, I am not even sure how our player would be able to account for the different quality versions. There is no indication of bitrate or bandwidth, simple an LQ or HQ in the URL. Perhaps the best solution would be to ask your ad network for only the HQ ads.

Up Down

daniel_yokoyama

User  
0 rated :

Hi Todd, thanks for getting back on this.
Our <MediaFiles> example does include a "bitrate" attribute as defined per VAST standard, so I'd assume this to be the deciding factor for bandwidth detection on VAST level.

For now we're asking our ad providers to supply the VAST with files listed from high to low quality, but it would be fantastic to see bandwidth detection for VAST in a future JW Player update. So if it's on the roadmap it would be great to hear about it.

Thanks,
Daniel

Up Down

Todd

JW Player Support Agent  
0 rated :

Thanks for pointing that out. I must have been looking for the bandwidth parameter that HLS uses. Our engineers verified that we do not use the bitrate in our calculation, only the width.

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