Chrome browser transcodes audio when casting to Chromecast Audio

[merak2000]

Dear community

I use the following setup to hear internet radios:

• The cast source device is a Google Chrome browser, the version is updated and it runs on capable hardware with Windows 10 also updated. 
• The cast target device is a Google Chromecast Audio, optically connected to one of the DAC inputs of a Primare I22 amplifier.
• The devices are connected to the home WLAN through the same WiFi access point using the 802.11n protocol, the actual connection speed being about 72Mbps.

Now, regardless of the internet radio streamed bitrate, Chrome seems to send to the Chromecast Audio the same bitrate of about 120 kbps. This would suggest to me some kind of transcoding happens internally to the browser, so that some strange (il)logic forces the Chrome browser or its standard audio player plug-in to transcode the audio stream BEFORE sending it to the Chromecast. 

Oddly enough this happens even if the radio station bitrate is lower than 120 kbps. I attach some screenshots for reference.

Naim Radio 320 kbps

Radio Paradise Mellow Mix FLAC

Radio Paradise low bitrate (32kbps)

@djtetei - I read several posts from you on the matter, you seem to be a subject expert 😉, would be glad for your support

Thanks in advance
Giulio

[Jeran]

Hey there merak2000,

I apologize for the late response, and I appreciate your patience! While I'm not an expert on the subject matter, transcoding is currently expected on certain sites that aren't Chromecast-enabled. Some users expressed interest in being able to add media remoting support for audio-only sites and avoid transcoding, and Google is always looking for ways to improve. In this case, I'd encourage you to submit feedback in the Google Home app. The more feedback Google receives regarding a specific feature, the more likely they are to prioritize it.

Let me know if you have any more questions, and I'd be happy to help where I can.

Best regards,

Jeran

[merak2000]

Hi Jeran

thanks for replying. I actually was not aware there was a difference between "casting a tab" and having a "Chromecast enabled site". I was assuming that the communication protocol between Chrome and the Chromecast audio was designed in such a way

• to have either the Chromecast Audio picking up the audio stream directly from the source indicated by the browser (as it may be for a Chromecast enabled site or app) or
• to have the browser sending to the Chromecast the native audio stream, as it is received from the source and without any form of transcoding.

I realise that such an approach works provided that the downstream DAC (as in my case the Chromecast Audio is optically connected to a digital amplifier) is capable to decode such a stream.

Perhaps the Engineers chose a (very) conservative approach and decided, in presence of a Chromecast Audio digitally connected to an external DAC, to have Chrome feeding the device with something they were sure that any DAC  would be able to handle (I suspect the 128kb/s MP3 stream I see is a good candidate for that)

This however cancels all the point of having a device like a Chromecast Audio connected to a high quality DAC (at least when the source is a browser). It's a also shame that just a few apps seems to be chromecast enabled (and I am not even sure Chromecast-enabled is the same as Chromecast-AUDIO-enabled, will check)

Many thanks for having taken the time to answer, and regarding the feedback to Google, well, I tried to discuss this with the google chromecast support. We are at the 20th email (and counting) and so far nobody among the 1st line support agents who wrote me seems to have even got a clue of the issue.

All what I could get so far are pre-written answer templates. That's very, very disappointing.

All the best,
Giulio

[Jeran]

Hi Giulio,

Thank you for your email. I understand your frustration. It is unfortunate that the Chromecast Audio does not support high-quality audio streams directly from the browser. I agree that it was a conservative decision by choosing to use a lower-quality MP3 stream, as this was likely made to ensure that the Chromecast Audio would be compatible with a wide range of devices. However, this decision does not work for users who want to use Chromecast Audio with a high-quality DAC.  It would be great if there were more apps that were Chromecast-enabled, and if the Chromecast Audio could decode higher-quality audio streams. I'll definitely pass on your feedback to Google as well.

I hope this helps. Please let me know if you have any other questions.

Best regards,

Jeran

[Jeran]

Hey there merak2000,

Do you have any more questions that I can address? 

Thank you,
Jeran

[merak2000]

Hey Jeran

no, thanks, no more questions.

I appreciated you forwarded the feedback though! 🙂

All the best
merak2000

[Jeran]

Hiya merak2000,

No problem at all! In that case, I'll go ahead and lock this thread in 24 hours. If you have any more questions in the future, feel free to create a new thread.

Have a good one!

Best regards,
Jeran