AAC codec

Owain Phillips_2 · ‎2018-07-05

Posted on July 05, 2018 at 10:40

Hi,

I am searching for AAC Codec for STM32F4 but struggling to find anything on st.com.

Can anyone point me to a supplier preferably ST. I find stuff at STM for MP3 and WMA but cannot find AAC.

I have seen press announcements saying ST has codec's; but maybe this was an over zelous marketing man...

â€œFurther Details on Development Support:

The extensive development ecosystem now in place includes STâ€™s STM32F429I-DISCO Discovery kit for STM32F429/STM32F439 and STM32F401C-DISCO for STM32F401.

In addition, developers using the STM32F429/39 can already use the STM32429I-EVAL full-featured evaluation board for the STM32F429, which features a 4.3-inch display, or the STM32439I-EVAL for STM32F439, which has a 5.7-inch display.

A complete audio IP package is available on request from ST, containing functions ranging from codecs optimized for STM32F4, such as MP3, WMA, AAC and voice codecs to sound-processing algorithms leveraging the high performance of the STM32F429/F439. These include smart volume control, filters for loudness, bass mix and other controls, and stereo widening and synchronization utilities such as sample-rate converters and clock-drift compensation.â€�

AvaTar · ‎2018-07-05

Posted on July 05, 2018 at 11:25

A complete audio IP package is available

on request

from ST,

...

I assume this means directly to ST, and not on public download or a public forum.

And it might not be for free (as in free beer).

Owain Phillips_2 · ‎2018-07-05

Posted on July 05, 2018 at 12:05

You may be right. I think AAC is poprietry and not free?

How to ask STM for that?

We currently use an AAC codec that we bought in; but its using a lot of CPU and its a binary library. So not visible what processor features been used. I suppose I could disassemble it.

AvaTar · ‎2018-07-05

Posted on July 05, 2018 at 12:18

I think AAC is poprietry and not free?

Supposedly yes. Wikipedia says :

... However, a patent license is required for all manufacturers or developers of AAC codecs. ...

How to ask STM for that?

A sales representative or FAE ?

I suppose I could disassemble it.

Tools like

objdump

can do this, but I'm not sure it it's worth it.

You would probably like to re-compile the C sources with different settings. Disassembled code would hardly do that.

Owain Phillips_2 · ‎2018-07-05

Posted on July 05, 2018 at 17:15

I have posted a support request. So should get something back.

The disassembly would show if FPU, arm neon or other special instructions were being used.

Don't know if that is relevant. Not sure if this is a fixed point of floating point codec; I am no expert here.

AvaTar · ‎2018-07-06

Posted on July 06, 2018 at 07:15

I would guess no FPU usage. Those lossy audio/video codecs are usually based on some spectral 'rounding', and there are plenty of integer-based algorithms for functional transformations around.