Hacker News: lesscraft

New comment by lesscraft in "FFmpeg 9.1's new AAC encoder"

lesscraft — Thu, 02 Jul 2026 02:18:12 +0000

You can use -q:a, for "true" VBR, but its metrics are a few percent (imperceptable, we still win) less. "The benchmarks I posted were done mainly on 44.1Khz. I tuned by ear on 48Khz data though, so some of the windowing/transient logic is tied to 48Khz. It translated to 44.1Khz well enough that I left it as-is, since the timing difference isn't that large."

New comment by lesscraft in "FFmpeg 9.1's new AAC encoder"

lesscraft — Wed, 01 Jul 2026 18:49:17 +0000

The issue was twofold, on one hand, using TNS on top of PNS meant the noise that got inserted was shaped by TNS, which is nonsense since the decoder generated the noise, not the encoder. This made PNS explode. The second, biggest issue was that using PNS in combination with any stereo tools resulted in noise leaking in both channels equally, ruining stereo imaging. So the best and only thing to do was to enable PNS only if the band in both channels is noise (or is sufficiently non-tonal and masked).

New comment by lesscraft in "FFmpeg 9.1's new AAC encoder"

lesscraft — Wed, 01 Jul 2026 18:42:22 +0000

Pretty much all DACs run at 48Khz by default due to operating systems picking it as a sane default.

New comment by lesscraft in "FFmpeg 9.1's new AAC encoder"

lesscraft — Wed, 01 Jul 2026 18:41:16 +0000

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

New comment by lesscraft in "FFmpeg 9.1's new AAC encoder"

lesscraft — Wed, 01 Jul 2026 18:39:53 +0000

The benchmarks were made using afconvert on OSX with the default VBR settings.