MP4: ACC or MP3? + DGIndex: WAV or AC3?

[mizumi]

Hi all!

I want to enconde a video using mp4 as container and x264 as codec. I want to extract the audio as WAV from DGIndex, synchronize it with another WAV file (the video will have 2 audio tracks) and finally convert the WAV to ACC or MP3 for final enconding.

I read that extracting AC3 from DGIndex gives better quality than WAV (don't know if that's true). Can anyone confirm that?

I want to work with a lossless audio codec, so in case the statement that AC3 gives better quality is true, will I loose noticable quality by extracting it as WAV? Since I need edit the audio synchronizing and stuff, there's no point in extracting audio as AC3 since it's lossy and I would be losing quality in the end, I guess.

Do you extract audio as AC3 or WAV? Which codec do you use to edit & synchronize audio?

To extract the audio from DGIndex should I extract it as WAV or AC3? I read that AC3 gives better quality.
As output file sound, should I use ACC or MP3 as audio?

Thank you!

[sneaker_ger]

Since you're re-encoding the audio anyways, it shouldn't matter whether you extract as AC3 or as WAV. You have to decompress at some point. I'd use AAC for mp4, it offers great quality while at the same time offering great compatibility.

[tebasuna51]

MP4: ACC or MP3?

AAC: best quality/size and multichannel support

DGIndex: WAV or AC3?

AC3: maybe you can use the AC3 without recode or use other more flexible decoder than DGIndex, like eac3to, BeHappy, ...

[mizumi]

I'll be using an audio from DVD, which original sound codec is AC3, but it's lossy, so wouldn't it be best to extract the track as WAV in order to edit? I'll be synchronizing and saving the file some times as a backup. When doing that the codec I've read that you need to be using a lossless codec so I should convert AC3 to some lossless codec?

Is configuring ACC any different from mp3? Could you gave me some basic standard configuration values for VHS and DVD quality (kbps, hz and CBR or VBR)? With MP3 I used to use CBR, 44100 hz and 192kbps. I tried finding a guide about configuring ACC with no luck yet.

[sneaker_ger]

1.) it's called "AAC", not "ACC"
2.) The settings depend on the encoder, I'd recommend NeroAacEnc with -q 0.4 for starters
3.) Yes, using lossless codecs for intermediate files is recommended, as each encoding to a lossy format results in a quality loss. But you don't lose any quality if you:
- extract the AC3 track using DGIndex, because DGIndex doesn't modify the track - it is copied 1:1 from the source
- extract to WAV, because "WAV" usually refers to totally uncompressed audio data with a wave header - this also has no quality loss
You can choose either of them, the only quality loss you have is on the final encode to AAC (but only strictly speaking, because it's not something you will hear, it's "transparent" unless you use a very low bitrate)

[SeeMoreDigital]

It's also possible to mux the original AC3 audio stream within the .MP4 container...

[mizumi]

Thanks a lot! Do you recommend any specific program for converting to AAC?

[kypec]

For me, nothing can beat Nero AAC Codec (http://www.nero.com/eng/downloads-nerodigital-nero-aac-codec.php)

[SeeMoreDigital]

Thanks a lot! Do you recommend any specific program for converting to AAC?Personally, I use LoRd_MuldeR's LameXP v4.01 Final (http://forum.doom9.org/showthread.php?t=157726) Which offers the ability to generate AAC files using Nero's AAC encoder...

[mizumi]

I'll try both LameXP and Nero AAC. Thank you!

Note: if you download nero aac, it has a pdf file where it explains how to convert to AAC.

[kypec]

I'll try both LameXP and Nero AAC.
You don't have to try "both" to get first impressions.
LameXP is nothing but a GUI/front-end to various command line encoders -> for conversion to AAC it's gonna use NeroAAC codec anyway.
For video dubbing processes and simple conversions from AC3/DTS -> AAC (M4A) I'd suggest to use eac3to (http://forum.doom9.org/showthread.php?t=125966)-> nothing beats its universatility in this area.

[mizumi]

I know, what I meant is that I would try both to see if I like better the raw process or using a GUI. Thanks for suggesting the program. I'll check that out too :)

[IgorC]

For me, nothing can beat Nero AAC Codec (http://www.nero.com/eng/downloads-nerodigital-nero-aac-codec.php)
Everybody can have own opinion. It's ok.

Though If somebody wants to see some results. Public Multiformat Listening Test @~64 kbps[2011]. Nero/Apple HE-AAC, CELT, Vorbis (http://forum.doom9.org/showthread.php?t=160185)

Popularity is not the same thing as real quality.

[mizumi]

The NeroAAC tutorial says to use *.WAV as input file and *.mp4 as output file. Something like this:

d:\NeroAAC>neroaacenc -q 0.5 -if *.WAV -of *.mp4.

I wonder if as input file can I use something else besides WAV (like AC3, for example) and as output file *.AAC.

I wanted to use the Audio Cutter in Megui but it doesn't accept *.mp4 files, so I would need to use *.AAC... I did try using the command with AAC as output file and seems to play fine:

d:\NeroAAC>neroaacenc -q 0.5 -if *.WAV -of *.AAC.

I just would like that someone confirms that it's fine even if the tutorial doesn't mention it.

[tebasuna51]

...
I wonder if as input file can I use something else besides WAV (like AC3, for example)
NeroAacEnc is only a encoder, if the input file is a encoded file you need a decoder first, for instance:

eac3to *.ac3 stdout.wav | NeroAacEnc -q 0.5 -if - -of *.mp4

or other decoders like Azid (in BeLight), NicAudio (in BeHappy), Foobar2000 ...

and as output file *.AAC.
Nope, NeroAacEnc only output AAC audio in MP4 container.

You need extract the aac audio (ADTS headers) with MP4Box for instance.

[mizumi]

Oh, I see! Now I understand. Thank you :)

[mizumi]

As you may know from reading this thread, I converted the audio with NeroAACenc from WAV to MP4. Now I want to mux it into an mp4 video using MeGUI. Since the audio is in MP4, I have used MP4Box to demux the AAC file from the MP4. And have used the MeGUI to mux the video with the audio. The question would be if I can mux directly the mp4 into the video or do I need to demux the AAC audio to mux it into the video?

[tebasuna51]

... The question would be if I can mux directly the mp4 into the video ...?

Of course.

[mizumi]

good to know ;)
thank you!