![FFmpeg NMR AAC Encoder: Audio Evaluation Update [Aug 2026]](https://preview.redd.it/g1iy40t8y1kh1.png?width=140&height=78&auto=webp&s=d49b25389d8b35f04193d2605f4181ad4222db1e)
▲ 16 r/ffmpeg
FFmpeg NMR AAC Encoder: Audio Evaluation Update [Aug 2026]
The last four weeks have been very busy, as this repository shows.
Full text:
u/IgorCv2 — 3 days ago
u/IgorCv2
▲ 9 r/AudioCodecLab
FFmpeg NMR AAC Encoder: Audio Evaluation Update [Aug 2026]
Hello, ladies and gentlemen.
The last four weeks have been very busy, as this repository shows.
FFmpeg developer Lynne managed to significantly improve the quality on killer samples https://code.ffmpeg.org/FFmpeg/FFmpeg/issues/23845#issuecomment-54547
So I decided to put the encoder to the test using previously untested samples, in order to avoid bias from using samples that the encoder had already been specifically tuned for.
Tested AAC encoders:
CBR encoders:
- FFmpeg NMR (r1) - commit 95a888b9ca (2 July, 2026)
- ^(-hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder nmr -cutoff 16000 %d)
- FFmpeg NMT (r6) - commit 6bcfae06a7 (2 Aug, 2026
- ^(-hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder nmr %d)
- Apple AAC CBR
- ^(qaac 2.70, CoreAudioToolbox) ^(7.10.9.0)^(, AAC-LC Encoder, CBR 128kbps, Quality 96)
VBR encoders:
- FFmpeg NMT (r6) - commit 6bcfae06a7 (2 Aug, 2026) https://code.ffmpeg.org/Lynne/FFmpeg/commit/6bcfae06a7edcc08ce9ac83e2cc292cd141057e2
- ^(-hide_banner -loglevel error -i pipe:0 -c:a aac -q:a 1.0 -aac_coder nmr %d)
- Apple AAC VBR
- ^(qaac 2.70, CoreAudioToolbox) ^(7.10.9.0)^(, AAC-LC Encoder, TVBR q64, Quality 96)
>>> Download: Audio samples,logs and application for blind tests <<<
Results:
Observations:
Moving from r1 to r6 might not seem like a huge step forward, but considering that there was literally only one month between these two revisions, it is a very impressive improvement.
r6 shows a clear improvement on difficult samples. As visible in the graph, it never drops below 3.0 (“slightly annoying”), while r1 goes as low as 2.5.
The VBR encoder looks promising too.
Overall there has been good progress. Transients and electronic music are still the main area that could be improved
u/IgorCv2 — 3 days ago
▲ 91 r/ffmpeg
MP3 Ain’t Dead Yet: LAME 4.0 Arrives
MP3 was standardized in 1993, but it is still widely used today because it works almost everywhere while deliver very good quality.
Now LAME 4.0, a new version of the open-source MP3 encoder , has been released.
Check here https://lame.sourceforge.io/ . And development of LAME 4.1 is already underway.
LAME has performed very well in public listening tests
MP3 isn't old. It is mature!
When a format is good enough, reliable and universally supported, it can stay relevant for a very long time.
Original thread https://www.reddit.com/r/AudioCodecLab/comments/1v4rd3b/mp3_aint_dead_yet_lame_40_arrives/
u/IgorCv2 — 26 days ago
▲ 244 r/musichoarder
MP3 Ain’t Dead Yet: LAME 4.0 Arrives
MP3 was standardized in 1993, but it is still widely used today because it works almost everywhere while deliver very good quality.
Now LAME 4.0, a new version of the open-source MP3 encoder , has been released.
Check here https://lame.sourceforge.io/ . And development of LAME 4.1 is already underway.
LAME has performed very well in public listening tests
MP3 isn't old. It is mature!
When a format is good enough, reliable and universally supported, it can stay relevant for a very long time.
Original thread https://www.reddit.com/r/AudioCodecLab/comments/1v4rd3b/mp3_aint_dead_yet_lame_40_arrives/
u/IgorCv2 — 26 days ago
MP3 Ain’t Dead Yet: LAME 4.0 Arrives
MP3 was standardized in 1993, but it is still widely used today because it works almost everywhere while deliver very good quality.
Now LAME 4.0, a new version of the open-source MP3 encoder , has been released.
Check here https://lame.sourceforge.io/ . And development of LAME 4.1 is already underway.
LAME has performed very well in public listening tests
MP3 isn't old. It is mature!
When a format is good enough, reliable and universally supported, it can stay relevant for a very long time.
u/IgorCv2 — 26 days ago
▲ 6 r/AudioCodecLab
Listening Test of the FFmpeg 9.1 NMR AAC Encoder @ 128 kbps [Test #2]
Hi everyone, this is the second listening test of the new FFmpeg NMR AAC encoder.
FFmpeg developer Lynne has made very interesting progress on the new NMR AAC encoder:
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23837
The idea was to put these latest improvements to the test and here are the results.
Tested AAC encoders:
- FFmpeg NMR (r1) - Master build from July 10, 2026 (tested in first test)
- ^(-hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder nmr -cutoff 16000 %d)
- FFmpeg NMT (r2) - PR 23837 build.
- ^(-hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder nmr -cutoff 16000 %d)
- Apple AAC CBR
- ^(qaac 2.70, CoreAudioToolbox) ^(7.10.9.0)^(, AAC-LC Encoder, CBR 128kbps, Quality 96)
- Apple AAC ABR
- ^(qaac 2.70, CoreAudioToolbox) ^(7.10.9.0)^(, AAC-LC Encoder, ABR 128kbps, Quality 96)
>>> Download: Audio samples,logs and application for blind tests <<<
Results:
While this was a personal test and the encoder was tuned by FFmpeg developers using some of these samples, the FFmpeg AAC encoder shows a very significant quality improvement in a remarkably short period of time. 🚀
A public test with completely new samples would still be essential for a final evaluation.
Hopefully tomorrow I will also post detailed descriptions of the artifacts, including the timestamps where they were identified, along with a statistical analysis of the results.
A big thank you goes to Kamedo2 for making graph creation such an easy task!
https://listening-test.coresv.net/graphmaker6.htm
https://listening-test.coresv.net/faq6.htm
IgorC
AudioCodecLab
u/IgorCv2 — 1 month ago
▲ 38 r/ffmpeg
AAC-LC 128 kbps Listening Test [CBR/ABR] - (Evaluation of FFmpeg 9.1 new AAC encoder)
Hello everyone! This is my personal listening test. 😄
The test contains 12 audio samples and compares five AAC encoders at approximately 128 kbps:
- FFmpeg NMR - new FFmpeg 9.1 AAC encoder - https://github.com/BtbN/FFmpeg-Builds/releases/tag/latest - ffmpeg-master-latest-win64-gpl.zip (tested build is July-10-2026)
- FFmpeg twoloop
- FDK-AAC CBR
- Apple AAC CBR
- Apple AAC ABR
Settings using foobar2000 converter :
- FFmpeg NMR:
- --hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder nmr -cutoff 16000 %d
- FFmpeg twoloop
- -hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder twoloop -cutoff 16000 %d
- FDK-AAC CBR
- fdkaac 1.0.5, libfdk-aac 4.0.1, CBR 128kbps
- Apple AAC CBR
- qaac 2.70, CoreAudioToolbox 7.10.9.0, AAC-LC Encoder, CBR 128kbps, Quality 96
- Apple AAC ABR
- qaac 2.70, CoreAudioToolbox 7.10.9.0, AAC-LC Encoder, ABR 128kbps, Quality 96
Download: Audio samples and logs
Sample-Rate Handling for the FFmpeg NMR AAC Encoder
According to an FFmpeg developer, the NMR AAC encoder is optimized for 48 kHz. Therefore, all test files were resampled to 48 kHz using SoX with the Very High, 168 dB quality setting.
The processing chain was:
Original WAV → SoX resampling to 48 kHz/24-bit → FFmpeg NMR AAC encoding → AAC decoding to 48 kHz/24-bit WAV → SoX resampling back to 44.1 kHz/24-bit
This process is safe and transparent. At these quality settings, the SoX resampling and 24-bit intermediate files don't introduce any audible differences.
u/IgorCv2 — 1 month ago
AAC-LC 128 kbps Listening Test [CBR/ABR] - (Evaluation of FFmpeg 9.1 new AAC encoder)
Hello everyone! This is my personal listening test. 😄
The test contains 12 audio samples and compares five AAC encoders at approximately 128 kbps:
- FFmpeg NMR - new FFmpeg 9.1 AAC encoder - https://github.com/BtbN/FFmpeg-Builds/releases/tag/latest - ffmpeg-master-latest-win64-gpl.zip (tested build is July-10-2026)
- FFmpeg twoloop
- FDK-AAC CBR
- Apple AAC CBR
- Apple AAC ABR
Settings using foobar2000 converter :
- FFmpeg NMR:
- --hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder nmr -cutoff 16000 %d
- FFmpeg twoloop
- -hide_banner -loglevel error -i pipe:0 -c:a aac -b:a 128k -aac_coder twoloop -cutoff 16000 %d
- FDK-AAC CBR
- fdkaac 1.0.5, libfdk-aac 4.0.1, CBR 128kbps
- Apple AAC CBR
- qaac 2.70, CoreAudioToolbox 7.10.9.0, AAC-LC Encoder, CBR 128kbps, Quality 96
- Apple AAC ABR
- qaac 2.70, CoreAudioToolbox 7.10.9.0, AAC-LC Encoder, ABR 128kbps, Quality 96
Download: Audio samples and logs
Results:
Sample-Rate Handling for the FFmpeg NMR AAC Encoder
According to an FFmpeg developer, the NMR AAC encoder is optimized for 48 kHz. Therefore, all test files were resampled to 48 kHz using SoX with the Very High, 168 dB quality setting.
The processing chain was:
Original WAV → SoX resampling to 48 kHz/24-bit → FFmpeg NMR AAC encoding → AAC decoding to 48 kHz/24-bit WAV → SoX resampling back to 44.1 kHz/24-bit
This process is safe and transparent. At these quality settings, the SoX resampling and 24-bit intermediate files don't introduce any audible differences.
Hardware used during testing
Topping E70 DAC
Topping L70 Headphone amplifier
Headphones Sennheiser HD 800.
Cabling: Balanced DAC-to-headphone amplifier connection; original Sennheiser HD 800 headphone cable.
-
IgorC
AudioCodecLab
u/IgorCv2 — 1 month ago