Slow quality switch with limitBitrateByPortal

[jakobrahm]

When using limitBitrateByPortal and, for instance, go from a small screen to fullscreen the top quality index updates pretty fast but the actual quality switch sometimes takes minutes (depending on buffer size etc.). Is there a way to drop the buffer when the quality index has changed? setFastSwitchEnabled doesn't seem to do the trick.

[kjnsn]

Have you tried using BOLA with enableBufferOccupancyABR(true)?

[jakobrahm]

@kjnsn Thank you! It didn't work either though. We ended up forking the repo and modified setElementSize (called by checkPortalSize) to use window instead of the video element. In our case the most users will enter fullscreen and therefore we can assume that the portal size is the same as the window size.

[dsilhavy]

This should work with fastSwitchEnabled. Re-evaluate the current behavior, a switch up should be performed quickly.

[eduter]

So, should this (from the docs about fastSwitchEnabled) still be honored, even with limitBitrateByPortal enabled?

When enabled, The maximum time to render a higher quality is current time + (1.5 * fragment duration).

We're getting complaints from people who go into fullscreen from our embedded videos and the quality looks terrible for several seconds. We're having to lower the buffer times, which is not ideal, to reduce the problem. I tried disabling limitBitrateByPortal when entering fullscreen, but that had no effect.

Does anyone know a way to get a high bitrate ASAP after entering fullscreen, without wasting a lot of bandwidth for users watching in a small viewport?

[dsilhavy]

So, should this (from the docs about fastSwitchEnabled) still be honored, even with limitBitrateByPortal enabled?

When enabled, The maximum time to render a higher quality is current time + (1.5 * fragment duration).

We're getting complaints from people who go into fullscreen from our embedded videos and the quality looks terrible for several seconds. We're having to lower the buffer times, which is not ideal, to reduce the problem. I tried disabling limitBitrateByPortal when entering fullscreen, but that had no effect.

Does anyone know a way to get a high bitrate ASAP after entering fullscreen, without wasting a lot of bandwidth for users watching in a small viewport?

In theory, fastSwitchEnabled should be independent of limitBitrateByPortal. If you enable limitBitrateByPortal then AbrController._filterByAllowedSettings will filter the available representations by portal size. The decision to which quality to switch is based on the available representations. If the ABR rules allow an upswitch then one of the next steps is to decide on the type of the switch (fastswitch vs "normal" switch)

How do you define "several seconds". Does your fragment duration allow a for a faster switch and the player is not switching up? Also can you confirm that the ABR rules would allow an immediate quality upswitch?

In theory you could handle such a case in the application yourself. You register for fullscreen events and then use setRepresentationForTypeById with forceReplace=true to replace the old quality with the new quality.