[mcnaugha]

Source dont need to be exact as they will get downsampled to 44.1 once detected.

Not true. Qualcomm informs developers that only content that is already 16/44.1 is supported for aptX Lossless (over Classic BT). They don’t do any transcoding for aptX Lossless. There is no time, nor is there energy allotted for that. The chips are powerful for their size but they’re not that powerful yet.

 

[helmutcheese]

Ideally you do not want files down/up samples you want bit perfect.

 

[Spektykles]

Not true. Qualcomm informs developers that only content that is already 16/44.1 is supported for aptX Lossless (over Classic BT). They don’t do any transcoding for aptX Lossless. There is no time, nor is there energy allotted for that. The chips are powerful for their size but they’re not that powerful yet.

This is simple not true, i dont know where you got it but qcom clearly stated they will downsampling everything to fit the bandwidth. Also those are processed at the source (laptop, smartphone,...) and not the sink (QCC chip).

 

[helmutcheese]

AFAIR they said anything above 16/44.1 or conditions not allowing the full 1.2Mb/s (approx.) will cause Lossless to fall back to Adaptive so it will then be 24/48 or 24/96 Lossy again.

 

[Spektykles]

AFAIR they said anything above 16/44.1 or conditions not allowing the full 1.2Mb/s (approx.) will cause Lossless to fall back to Adaptive so it will then be 24/48 or 24/96 Lossy again.

1) For any content above 16/44.1, it will be downsampled to 16/44.1 (provided the link quality is good enough for 1.2Mbps). This is still superior than 24/96 Adaptive lossy. aptX Lossless will simply not drop into Adaptive lossy just because the content isnt exact match.
2)Of couse when the link quality is bad, aptX Lossless will be forced to drop into Adaptive lossy. This is the case for any content, be it proper 16/44.1 or downsampled HiRes contents.

 

[Spektykles]

This is from O11111's doc. Per qualcomm docs, 16/48 will be downsampled and streamed losslessly. Anything else like 24/48 or 24/96 of course will be chopped (downsampled) lossy, but still will be transfered via 16/44.1 aptX lossless stream.

 

[mcnaugha]

This is from O11111's doc. Per qualcomm docs, 16/48 will be downsampled and streamed losslessly. Anything else like 24/48 or 24/96 of course will be chopped (downsampled) lossy, but still will be transfered via 16/44.1 aptX lossless stream.

What you've screenshotted here, supports what I said.

There is no evidence in this screenshot that they are downsampling 24-bit or Hi-Res. There would be no point in having or discussing references to 24/96 in the specs. Audiophiles would have their guts for garters. It is totally subjective to claim that lossless 16/44.1 is somehow better than lossy 24/44.1, 24/48, 24/96. They wouldn't get away with it. Every SoC with lossless would never show the options to control the availability of 48kHz and 96kHz.

16-bit 48kHz being downsampled is something else altogether. That's a negligible impact on both the processor and listener. This is a positive thing.

 

[mcnaugha]

This is simple not true, i dont know where you got it but qcom clearly stated they will downsampling everything to fit the bandwidth. Also those are processed at the source (laptop, smartphone,...) and not the sink (QCC chip).

You're trying to pass this off as Qualcomm but it's not what Qualcomm said in 2021 and the developer content watermark isn't showing here. It is insane to think that they would convert all 24/44.1, 24/48, 24/96 content to 16-bit 44.1 and transmit losslessly.

Qualcomm told the hardware developers, I know, that lossless only takes place for 16-bit/44.1kHz sources and that everything else is processed with the usual lossy aptX Adaptive codec. I can accept 16-bit 48kHz being included in that either by downsampling or in the Gen 2 and later SoC's downsampling wouldn't be required when using LEA. Everything else is "business as usual", pumped through the lossy process because this preserves more of the original source than downsampling would.

 

[Spektykles]

You're trying to pass this off as Qualcomm but it's not what Qualcomm said in 2021 and the developer content watermark isn't showing here. It is insane to think that they would convert all 24/44.1, 24/48, 24/96 content to 16-bit 44.1 and transmit losslessly.

Qualcomm told the hardware developers, I know, that lossless only takes place for 16-bit/44.1kHz sources and that everything else is processed with the usual lossy aptX Adaptive codec. I can accept 16-bit 48kHz being included in that either by downsampling or in the Gen 2 and later SoC's downsampling wouldn't be required when using LEA. Everything else is "business as usual", pumped through the lossy process because this preserves more of the original source than downsampling would.

Well, we have no other option than doing a live test to demonstrate. You already have presumably all the correct gear to test it, from source to sink. Just try and check for yourself, to see if aptX lossless indeen downsample things or switch to Adaptive lossy.

 

[mcnaugha]

Well, we have no other option than doing a live test to demonstrate. You already have presumably all the correct gear to test it, from source to sink. Just try and check for yourself, to see if aptX lossless indeen downsample things or switch to Adaptive lossy.

The screenshot of the "Qualcomm aptX User guide" you showed, I have this whole document and it is clear that it has both "lossless mode" and "HQ mode", where HQ mode is the lossy mode. The phrase "scale-to-lossless" refers to the BT bit rate not to resampling sources. It must be "fed" 16/44.1 or 16/48 sources or it won't go into lossless mode. Any other sources will receive HQ mode. It only downsamples 16/48 on Classic BT. This shouldn't be downsampled on LEA but this guide has not been updated since the introduction of LEA support in S3/S5 Gen 2.

It's important to note that hardware vendors can also limit the codec. My Bose QC Ultra earbuds have had 96kHz disabled which is frustrating but may be to keep within their battery utilisation intentions. This leads to the aptX Adaptive logo appearing instead of the Snapdragon Sound logo when these connect.They have kept 48kHz enabled but this isn't useful for lossless because they have not enabled LEA in the current firmware. It is as though they don't know that 16/48kHz lossless is only possible via LEA.

I have to say though that I think I prefer my QCC3081 ear hooks to the Bose now because I can use them with my higher quality IEM's. Also it has access to 96kHz and the Snapdragon Sound logo displays when they connect.


I may have a bigger problem which I am trying to investigate. The ROG Phone 8 just shows 24-bit for the PCM Bit Depth. There is no option to switch the codec to 16-bit. I am contacting support but I don't hold out much hope of a good answer. I don't know where to check in their AOSP source code for where they could have hardcoded 24-bit only. So, it's hard to tell if we still get actual aptX Lossless with this current OS. We need an Android extension which shows the live BT bit rate at the top of the screen or something like that. It's the only way you can know, when you see a 1Mbps or higher bit rate. I think it is so sensitive and variable that they decided not to provide a default visual way to tell if you're enjoying lossless. The developer of Bluetooth Codec Changer might be our best hope for improved lossless monitoring in the future.

 

[cattboy]

Sorry to interrupt the lossless discussion

Is it confirmed the Creative BT‑L3 and BT-L4 dongle (that come with Zen headphone), pair&work with other BT Audio devices using the LC3 codec?

Itchyears writeup says it pairs with Nvidia shield so I'm assuming yes?

 

[helmutcheese]

Are you sure he did not mean he plugged it into the Shields USB port to use that way as I see no point in any using it with it any other way as it is a TX device not RX device.

 

[cattboy]

Are you sure he did not mean he plugged it into the Shields USB port to use that way as I see no point in any using it with it any other way as it is a TX device not RX device.

Thats what I'm not sure

Did Itchy plug in the dongle (tx) to shield and use the already paired headphone (rx)

Or plug in the dongle and paired it with something else (home speaker?, rx?)

 

[itchyears]

Thats what I'm not sure

Did Itchy plug in the dongle (tx) to shield and use the already paired headphone (rx)

Or plug in the dongle and paired it with something else (home speaker?, rx?)

Yes I plugged the included LE creative dongle to the Nvidia shields usb port and then paired with my creative zens hps.

I did not have any other LE devices or LE buds/hps to test it with.

I don't believe it would have the ability to pair with other devices really it seemed like it was Tailor made for the Zen headphones.

 

[cattboy]

I don't believe it would have the ability to pair with other devices really it seemed like it was Trailor made for the Zen headphones.

Thanks. Drat, hoping it allowed re-pairing with long press like other dongles . Love your work keep it up