Gomez et al. (2012) explain that there is a balance to be struck between energy usage, latency, piconet size and throughput when using the BLE technology. The results of our research show that LC3 is capable of delivering satisfactory audio quality with less throughput which then would have a direct effect on the other parameters mentioned by Gomez et al. (2012).

It is firmly stated by Meyer & Moran (2007) that people in their study were not able to detect shortcomings in audio above CD quality. We concur with this statement and perhaps make an even bolder claim, as our listening test used a reference track with a slightly higher caliber than a CD and the participants struggled to detect differences between this and the other low bitrate samples.

In the research provided by McPherson et al. (2016) a set of products was tested that utilize the WiFi, Xbee and BLE protocol. They conclude that none of these can deliver a latency low enough to match the demands of a music performance if the threshold is set to 10 ms. Since our results display a significant decrease in execution time for LC3 compared to aptX, this could potentially indicate that future products implementing this codec could match this requirement.

Schnell et al. (2021) provides a technical description of the LC3 codec and concludes that it clearly meets the requirements of the present solutions when it comes to: music streaming, wireless gaming headphones, etc. Our research supports these claims since the LC3 implementation delivered a fast execution time, to encode and decode audio, whilst also producing satisfactory audio quality, except for 64 kbps.

When performing a MUSHRA listening test Hines et al. (2014) compared the perceived audio quality of the AAC, MP3 and Opus codec. When using studio headphones a significant difference was noticed between 64 kbps (AAC) and higher bitrates. This is similar to our findings regarding LC3 as well. Additionally Hines et al. (2014) also performed the test using lower quality headphones and concluded that it was challenging to detect shortcomings above 48 kbps. The headphones was not a treatment in our research and thus this can not be affirmed although it seems likely to be the case.

4.5Future work

In the last section three suggestions of potential research are presented that could further elaborate and complement the topic at hand.

Real world usage

An interesting approach for future work would be to utilize the full Bluetooth stack by sending audio between hardware and measuring the execution time of the coding. This would be a more accurate representation of real world usage but such testing does require significantly more time and resources than what was available in this study, as well as LC3 implemented in available products which is still rare.

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Combinations

Further exploration could consist of trying different combinations of codecs, Bluetooth hardware and stack configurations. Identifying the optimal composition between them could provide valuable insights when it comes to the optimal usage of audio codecs in Bluetooth based systems.

Comparison of implementations

In this research there was only one implementation, of each codec, that was evaluated. If more libraries could be obtained it would be interesting to compare the different solutions with one another.

Multiple songs

A variant of this study would be to utilize several pieces of music, for both the quasi-experiment and the MUSHRA, in order to see how the codecs handle a difference in dynamic range and sonic information.

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