Hacker News Reader

Comment by booi | Hacker News Reader

Also the fact that hardware-accelerated AAC and even full AAC offload is ubiquitous in modern-ish hardware. I think my rice cooker can play AAC audio

View on HN

No one really offloads AAC, apart from Apple. Opus can be decoded on very cheap microcontrollers entirely in software using the reference library.

On a microcontroller doing nothing else sure. But on a phone, a tablet, a laptop, you absolutely want hardware decode to preserve your battery life.

That's their point though. Basically no modern phone/laptop/tablet other than Apple offloads audio decoding (of any codec) to hardware. You can check this on Android phones by installing the Codec Info app.

Snapdragon chips do (used in many/most androids), Samsung own exynos also does iirc.

If the OS/platform doesn't use it that could be another thing, but those chips do offer audio coded decoding, including aac

Yeah no. All chips in computers, tablets, etc. have hardware decode. Intel chips have hardware decode. AMD, Arm, Raspberry Pi, what have you.

I’m pretty sure no x86 chip has hardware decode/encode for audio. Together with dGPUs, they tend to have decoders for JPEG and decoders/encoders for H.264, H.265, AV1 and sometimes VP9.

They have hardware decoders for JPEG? I have never heard of this and it seems overkill considering how simple it is to decode.

https://rocm.blogs.amd.com/artificial-intelligence/rocjpeg-d...

https://alax.info/blog/1992

https://en.wikipedia.org/wiki/Unified_Video_Decoder added around H.265 in UVD 6.0

There’s also https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video#Hardwar...

Seems like Nvidia doesn’t support JPEG in NVDEC.

Audio decode is extremely cheap. It's true that a hardware implementation will be more efficient, but really not a whole lot more.

on a 30MHz microcontroller

There absolutely does, Android did with low power audio. They even goes a step further by offloading bluetooth processing into DSP.

I’m not in this space anymore but as of Android 5-6 era aac and bt is offloaded to hexagon dsp on qualcomm device.

You might be referring to this but on top of hardware decode some Bluetooth setups can send the actual AAC file to the headphones and decode it there.

Traditionally Bluetooth audio meant decoding and reencoding it into a crappier codec before transmission. So it's an efficiency and quality win.

I think some Google Pixel Bud Pro earphones do this for Opus but that is rarer (there's a few other codecs that have been done like this over the years by different manufacturers).

Reply on news.ycombinator.com