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FFmpeg 9.1's new AAC encoder

hydrogenaudio.org

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Re: FFmpeg 9.1's new AAC encoder

#41

Post by dcrazy »

skydhash wrote: post #33
zamadatix wrote: post #24

Earlier quoted context omitted.

Say it or don't but "I have evidence otherwise but don't think I should say" is just as bad a flame war gateway as tempting the junk science audiophiles directly.

I know that with oscilloscopes, it’s recommended to use 5x instead of nuquist 2x of the highest frequency you want to use., but the most reasonable argument I’ve heard for higher than 48kHz sampling is digital audio effects. But for the end result 48kHz is more than necessary. I can’t even hear any frequency above 17kHz.

Yes, bit depth headroom is very useful for audio production to avoid aliasing. Pro DAWs support 96KHz.

Re: FFmpeg 9.1's new AAC encoder

#42

Post by ksncksmckwkf »

jck86 wrote: post #28
cogman10 wrote: post #16

Man what a showcase for Opus this is. Don't get me wrong, this sort of thing is a valuable exercise and we are better off with better encoders for these older codecs. But look at the numbers for Opus on this benchmark. It simply blows all the AAC encoders out of the water even at 64 kbps.

Choosing a lossy audio codec has become such a no brainer. Either use opus and be done with it or if for some reason opus cannot be used then use aac for compatibility with insane high bitrate for good quality without having to do research on what encoder and mode to pick. Still having a good quality and default aac encoder is great. Though I don't get why it is mainly CBR.

[flagged]

Re: FFmpeg 9.1's new AAC encoder

#43

Post by cosmic_cheese »

repelsteeltje wrote: post #22
ndiddy wrote: post #17

Nice, I'm looking forward to seeing how this performs in practice. FFmpeg's previous AAC encoder produced poor quality output and often had irritating chirping artifacts, so I've always had to install Apple's Core Audio encoder on any computer I do video recording on to get decent sound. I've done A/B/X comparisons and found that a 320kbps MP3 sounds better than a 320kbps AAC encoded by FFmpeg, but about the same as…

Why not use a lossless codec if you care about quality? Or use Opus, descent for specht and works pretty much anywhere these days.

There are a ton of older, but still perfectly usable devices that support AAC well but not Opus.

Re: FFmpeg 9.1's new AAC encoder

#44

Post by dcrazy »

mcoliver wrote: post #14
HugoTea wrote: post #7

>FFmpeg's AAC DEcoder is busted with regards to stereo PNS, and the bug may be in other AAC decoders too, so we work around it in the encoder. Since no other encoder used PNS, the bug was not found until now. I don't know what PNS is, but I bet this has been bothering someone's niche use-case for 20 years

https://www.audiolabs-erlangen.de/content/resources/aesCodin...

Hah, this sounds like the audio equivalent of Netflix’s grain reconstruction.

Re: FFmpeg 9.1's new AAC encoder

#45

Post by kderbe »

ndiddy wrote: post #17

Nice, I'm looking forward to seeing how this performs in practice. FFmpeg's previous AAC encoder produced poor quality output and often had irritating chirping artifacts, so I've always had to install Apple's Core Audio encoder on any computer I do video recording on to get decent sound. I've done A/B/X comparisons and found that a 320kbps MP3 sounds better than a 320kbps AAC encoded by FFmpeg, but about the same as…

In the Hydrogenaudio discussion thread's metrics table, the new encoder scores better than Core Audio. But this is at constant bitrate (CBR) [edit: maybe not? see lesscraft's reply below]. Core Audio also has variable bitrate modes (TVBR) which the new encoder lacks.

So maybe Core Audio will continue to be the best when TVBR is available, but I'm hopeful the new FFmpeg encoder will be "good enough", especially if more folks find and contribute problem samples to help tune it.

Re: FFmpeg 9.1's new AAC encoder

#46

Post by madars »

ndiddy wrote: post #17

Nice, I'm looking forward to seeing how this performs in practice. FFmpeg's previous AAC encoder produced poor quality output and often had irritating chirping artifacts, so I've always had to install Apple's Core Audio encoder on any computer I do video recording on to get decent sound. I've done A/B/X comparisons and found that a 320kbps MP3 sounds better than a 320kbps AAC encoded by FFmpeg, but about the same as…

A useful project related to Apple's Core Audio is qaac - it wraps iTunes Windows DLL's in a standalone encoding tool with a CLI interface. I believe it even works under Wine on Linux: https://web.archive.org/web/20250814194428/https://www.andre... So you don't need a Mac or even a full iTunes installation to get high quality AAC encoding.

Re: FFmpeg 9.1's new AAC encoder

#47

Post by daneel_w »

superzazu wrote: post #8

> The encoder was mainly optimized for 48Khz audio. Get over it. It's 2026, resampling is free, 48Khz is the standard. 44.1Khz will work, and so will 96Khz but use 48Khz if you want the best quality. Is 48kHz really the standard nowadays?

Yes and no. It is the standard for audio in film, which explains the author's focus. But is the audio CD bigger and more "standarder" than DVD and Blu-Ray? I think they're equals, and I personally think this encoder only makes sense for video content. Given all the caveats the author mentions (in particular about the sample rate) I would steer clear from using it when ripping CDs.

Re: FFmpeg 9.1's new AAC encoder

#48

Post by theandrewbailey »

palmotea wrote: post #21
cogman10 wrote: post #16

Man what a showcase for Opus this is. Don't get me wrong, this sort of thing is a valuable exercise and we are better off with better encoders for these older codecs. But look at the numbers for Opus on this benchmark. It simply blows all the AAC encoders out of the water even at 64 kbps.

> Man what a showcase for Opus this is. I take it you mean this Opus ( https://en.wikipedia.org/wiki/Opus_(audio_format) ) not that Opus ( https://en.wikipedia.org/wiki/Claude_(AI) ). I read almost all the way through your comment thinking there was a decent probability you were saying this new AAC encoder was written with Claude Opus.

I've never been AI guy, and have more fascination with audio. I've long stopped being excited when I read "Opus" on HN. It's refreshing when it turns out to be the audio codec.

Re: FFmpeg 9.1's new AAC encoder

#49

Post by kderbe »

a1o wrote: post #38
cogman10 wrote: post #16

Man what a showcase for Opus this is. Don't get me wrong, this sort of thing is a valuable exercise and we are better off with better encoders for these older codecs. But look at the numbers for Opus on this benchmark. It simply blows all the AAC encoders out of the water even at 64 kbps.

I think the biggest issue with Opus is the problem with its specification being lacking, see: https://nothings.org/stb/stb_opus.html This essentially causes opus to never be used in games or in things in stores that may have issues with specific licenses.

This essay says it's not possible to make a public-domain implementation of Opus. But it could be released under BSD (as libopus is), which is fine for games, as evidenced by the Licenses section of the credits in many games.

Re: FFmpeg 9.1's new AAC encoder

#50

Post by booi »

ndiddy wrote: post #20
cogman10 wrote: post #16

Man what a showcase for Opus this is. Don't get me wrong, this sort of thing is a valuable exercise and we are better off with better encoders for these older codecs. But look at the numbers for Opus on this benchmark. It simply blows all the AAC encoders out of the water even at 64 kbps.

The biggest advantage for having a good AAC encoder isn't efficiency, it's that for nearly the past 2 decades the de facto standard for live streamed video has been RTMP with H.264 video and AAC audio. There is basically no support for any other codecs. If you want to send a video stream to Youtube or Twitch, you will be sending H.264 and AAC. If you want an idea of how ubiquitous this is, I just checked in OBS and i…

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
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