i.MX ProcessorsのトピックRe: AVB Demos, AVDECC entity definition, create custom

AVB Demos, AVDECC entity definition, create custom

jpa — Fri, 08 Nov 2024 14:34:00 GMT

As I understand it, in the AVB demos, there are binary .aem files that define the AVDECC stream configurations. I'm trying to use those demos on custom i.MX8MP hardware, and the ADC/DAC that is available has limited format and channel support.

Is there a binary .aem file that supports 8 channels, 32 bit LE at 48 kHz? If not, is there documentation for that file format or a utility that can be used to create such a configuration file (or some other approach that I should be considering) ?

Is "Hive Controller binaries and scrounging up a Windows PC" an answer, the only answer, the best answer?

John

Re: AVB Demos, AVDECC entity definition, create custom

jpa — Mon, 11 Nov 2024 13:00:04 GMT

Well, I think I can answer that last piece, myself, at this point. The Hive controller does not allow me to change the configurations. There are drop-downs that make it seem like it might, but the drop-downs are only populated with the current setting.

Re: AVB Demos, AVDECC entity definition, create custom

JosephAtNXP — Mon, 11 Nov 2024 18:51:56 GMT

Hi,

Thank you for your interest in NXP Semiconductor products,

What defines the stream configurations are the profiles that both sides set, quoting from AVB spec:

The vendor shall notify the certification facility of the range of format variants (for example, audio channels, video resolution and profile, etc.)

For your tests, you need to refer to the AVB demos by NXP which can be found here.

Your channel requirement is solved in this chapter:

10.3.2 Connect audio streams with different channel count

The avdecc entity model supports multiple stream formats with different channel counts (1, 2, 4, 6 and 8 channels) for the stream inputs/outputs. To change the stream inputs/outputs format, use the Hive controller to set the desired stream format on both talker and listener.

Regards

Re: AVB Demos, AVDECC entity definition, create custom

jpa — Tue, 12 Nov 2024 14:21:41 GMT

Hi, Joseph,

Thanks for responding. Have you tried what you're suggesting? When I run the Hive controller, I can see the configurations, and the Dynamic Info->Stream Format, but I cannot change the stream format. The only selection offered is the one that is set. For demo #22, that's AAF, 48kHz, PCM-INT-32, 2 channels. I was hoping to configure a profile as having an 8 channel stream, rather than 4 streams of 2 channels (or, in the case of profile #22, 2 streams of 2 channels).

Having said that, I have been able to configure ALSA's plug-ins to divide my 8 channel device into 4 2-channel devices, and they work, at least with aplay and arecord. When I use one of the pairs as the alsa device for this demo (#22 or #9/11), I get no errors that I recognize, but also no sound. More precisely, I get no sound that is related to the signal being put into the alsa device. When I make the connection in the Hive controller, I DO hear a faint high-pitched noise, so it's trying to do something.

I've attached the /var/log/avb and /var/log/avb_media_app logs from the talker and listener in case someone can see something I cannot.