Avantree has many aptX Low Latency supported Bluetooth transmitter: Priva III, Priva IIA, Audikast, Oasis, Leaf and TC026.
When them using aptX Low Latency codec(aptX LL), the audio delay will be ≤40ms that is even NOT detectable by human ears, which makes it ideal for watching TV/movies/video without any audio lag.
While, to achieve that, your Bluetooth headphones has also to be aptX LL supported. Otherwise, they will work using SBC codec with 220ms latency but not aptX LL codec, that is why you will have a latency between sound and image.
Bose QC35 does not support aptX LL codec, so when Bose QC35 works with Priva III, they will work under SBC codec but not aptX LL.
Here is the list of certified aptX Low Latency products on the market at the moment.
Bluetooth Audio Delay Experiment - aptX Low Latency vs others
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