Getting "Nero Audio Decoder 2" instance failed.

[rhaz]

Hi. I'm trying to convert .aac to .wav and I get this message. I do have neroAacDec.exe in eac3to dir and in win32 dir.

So I run 'eac3to file.aac file.wav -downStereo' or something like that. And I get:

AAC, 2.0 channels, 48kHz
Decoding with DirectShow (Nero Audio Decoder 2)...
Getting "Nero Audio Decoder 2" instance failed.
Aborted at file position 262144.

I have Nero 7 installed, but that doesn't change anything since Nero AAC decoder has been standalone for 9 years now, so quotes from eac3to wiki are outdated.

I use latest eac3to package and nero codecs. Win8x64 (not 8.1)

Pls help.

[sneaker_ger]

Get ffmpeg:
ffmpeg -i file.aac -ac 2 file.wav

Or, if you want eac3to to do the downmix:
ffmpeg -i file.aac file.wav
eac3to file.wav downmix.wav -down2

I think eac3to cannot open "raw" ADTS AAC directly.

[LoRd_MuldeR]

Originally Posted by rhaz

Hi. I'm trying to convert .aac to .wav and I get this message. I do have neroAacDec.exe in eac3to dir and in win32 dir.

So I run 'eac3to file.aac file.wav -downStereo' or something like that. And I get:

AAC, 2.0 channels, 48kHz
Decoding with DirectShow (Nero Audio Decoder 2)...
Getting "Nero Audio Decoder 2" instance failed.
Aborted at file position 262144.

I have Nero 7 installed, but that doesn't change anything since Nero AAC decoder has been standalone for 9 years now, so quotes from eac3to wiki are outdated.

I use latest eac3to package and nero codecs. Win8x64 (not 8.1)

Pls help.

Obviously it's not using (and not trying to use) the neroAacDec.exe program, but it's trying to use some DirectShow filter - that appears to be missing on your system.

The neroAacDec.exe command-line decoder is 100% standalone and not related to DirectShow at all. You can call it like this:

neroAacDec.exe -if input.mp4 -of output.wav

If I remember correctly, neroAacDec.exe does not support ADTS (that's what ".aac" files typically are!), but only AAC stored in an MP4 container.

You can use faad to decode ADTS instead:

faad.exe -o output.wav input.aac

[sneaker_ger]

Originally Posted by LoRd_MuldeR

Obviously it's not using (and not trying to use) the neroAacDec.exe program, but it's trying to use some DirectShow filter - that appears to be missing on your system.

^ This.

Note that NeroAacDec cannot open ADTS AAC, either.

[rhaz]

Hey thanks for reply, it works. I also tried without -ac 2 part and it gives same, so why add extra commands? What do they do? Also what does -i stand for?

But yeah, I'm going to stay with this ffmpeg command line. Cheers!

[LoRd_MuldeR]

Originally Posted by sneaker_ger

^ This.

Note that NeroAacDec cannot open ADTS AAC, either.

Well, that's why I said he can try faad.exe (instead of NeroAacDec) for that kind of file. But FFmpeg works too, of course

Originally Posted by rhaz

Hey thanks for reply, it works. I also tried without -ac 2 part and it gives same, so why add extra commands? What do they do? Also what does -i stand for?

With FFmpeg, the "-i" option is used to specify the input file. The output file is just appended.

With NeroAacDec, you have to use "-if" to specify the input file, and you have to use "-of" to specify the output file. With faad, you use "-o" to specify the output file and just append the input file.

Every program does it a bit different, because things would be to easy otherwise

[sneaker_ger]

Totally overlooked that in your post, sorry.

[rhaz]

Hey do you know how to set .wav output bitrate? it gives me 1.5k bitrate with 1gb file from 50mb 128kbps .aac file, looks like waste of space.

[LoRd_MuldeR]

Originally Posted by rhaz

Hey do you know how to set .wav output bitrate? it gives me 1.5k bitrate with 1gb file from 50mb 128kbps .aac file, looks like waste of space.

Wave files almost always contain "raw" PCM data, so the bitrate is defined by samples per second × bits per sample × number of channels!

There's nothing you can do about it, except for converting to a lower sampling frequency (which will destroy the higher frequencies) or converting to a lower bit depth (which will increase the noise level). Probably you want neither of that

When looking for a lossless compression, try FLAC oder APE (Monkey's Audio). Otherwise, if lossy compression is acceptable, use AAC, Vorbis or Opus - depending on your personal preferences.

[rhaz]

Hey thanks for all the help!