AAC (FDK) or AAC (LAV) in AVIDemux

[Alwyn]

A question for the audiophiles...

AVIDemux has two options for encoding the audio into AAC, FDK and LAV:


[Attachment 87879 - Click to enlarge]

I know even less about audio than I do video, so am interested in your thoughts about which would be preferred out of these two.

Thanks!

[gregalan]

According to listening tests FDK should be preferred over lav.
See here: https://trac.ffmpeg.org/wiki/Encode/HighQualityAudio

The AAC (lav) is the ffmpeg native aac encoder and is not the best quality, although it is acceptable for non critical use.

[Alwyn]

Thanks @Gregalan, I'll check it out.

[cholla]

If I was using AVIDemux & the audio was a low bitrate I would use AAC(FDK).
Better yet demux the video/audio.
Then use ffmpeg with aac_at for the codec.(Apple)
Or use QAAC.
Then remux & open in AVIDemux & use Copy in Audio.

I did a comparison of ffmpeg Native & AVIDemux AAC(lav).
The codec appears to be the same.
FFMPEG Native
Mediainfo:
Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 7 min 35 s
Source duration : 7 min 35 s
Bit rate mode : Variable
Bit rate : 128 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 6.90 MiB (3%)
Source stream size : 6.90 MiB (3%)
Default : Yes
Alternate group : 1
Menus : 3

FFPROBE: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)

AVIDemux AAC(lav)
FFPROBE: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 126 kb/s (default)
Mediainfo:
Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 7 min 35 s
Bit rate mode : Variable
Bit rate : 128 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 6.90 MiB (3%)
Default : Yes
Alternate group : 1

[geextah_2]

If you can use apple aac (with ffmpeg), it's much better than FDK and LAV, but if you slap enough bitrate on it, you won't notice a difference

[Alwyn]

Thanks Geextah, what sort of bitrate are you talking about? 192? I'm choosing the FDK or LAV in AVIDemux, a GUI; I'm not using FFMPEG via the command line.

[geextah_2]

I use apple aac with -q:a 2 which is around ~220k
But if you mean which bitrate to slap on it, everything above 160k will be fine for stereo (for normal usage, tv, laptop, phone, maybe not highend speakers/setup etc.) , I don't know how the bitrate gets distributed when there are multiple channels.

Do you need AAC for compatibility reasons? Because otherwise use opus @160k-190k

[videoAI]

AAC has several profiles, including Low Complexity (LC), High Efficiency (HE), and Main Profile (MF), among others. AVIDemux seems to generate AAC LC.

Why not use a modern FFmpeg GUI like Clever FFmpeg .. which gives you access to AAC, AAC MF, opus, & Vorbis to name a few.


[Attachment 87953 - Click to enlarge]

[cholla]

HI Alwyn,
I did the test in the post #4.
I just used the same audio rate as the file I was converting.
If I wanted better I would test with the maximum rate which is 320k.
Then listen to see if it sounds better.

I set AVIDemux to 224 for the AAC since the next setting was 384.
No option to set manually.
Maybe if a script was used maybe AVIDemux could be set to 320k for the audio AAC.
My understanding is most AAC has a 320k maximum.
I did not notice any difference in the quality over the 128k source file.

My vote is for AAC(FDK) with AVIDemux.

[Alwyn]

Thanks everyone, I'll go with FDK 192. It's mainly only for converting the audio in old MPEG files which have stereo MP3 audio tracks my NLE doesn't like for some reason.

[cholla]

@ Alwyn,
Would you post one of the videos you are having the problem with ?
I would like to play around with it.

I do not have a NLE as far as I know.