MeGUI: AC3 --> AAC (very frustrating)

[kartman_canada]

My apologies if this is posted elsewhere. I tried to search but didn't find much that helped.

I've got what I believe is the latest Nero Digital AAC tools (v1.1.34.2) and have fully updated MeGUI. I'm trying to convert an AC3 file (640kbps @ 5.1 channels) to an AAC file (192kbps @ 2.0 channels).The AC3 file is 1:34:30 and the MP4 that MeGUI produces is exactly the same overall length.

Here is the catch... after muxing the h.264 video stream together with the new AAC MP4 file, the video is in sync with the audio at the start but begins to drift until it's out by ~2-3s at the end. If I mux the same video but use the AC3 file into a MKV or TS or M2TS container everything is good right to the end. Therefore, I suspect the AC3 to AAC conversion.

After loading both the AC3 and AAC files into synced players, it seems the audio of the AAC is not at the same point at common timestamps even before muxing. (at first, I thought it was the muxing)

does any of this make sense? Am I doing something silly that is causing this issue?

From the logs, MeGUI seems to be doing some "pre-processing" of the AC3 and then feeding from STDIN but there's not much more info than that...

-help!

[ash925]

try using besweet.works for me every time.

[anonova]

try using besweet.works for me every time.
Could you expand on that, please? I'm having a similar problem with an mp2 to aac transcode.

[tebasuna51]

The AC3 file is 1:34:30 and the MP4 that MeGUI produces is exactly the same overall length.

If the ac3 file have same duration than converted mp4 (only audio) the problem can't be at audio conversion but at muxing step.

[Sharktooth]

this is the perfect "how to NOT do a bugreport".
also, if you consider i and most megui users never had such a problem...
megui version? OS? program used for ripping the DVD? logfile?

[kartman_canada]

this is the perfect "how to NOT do a bugreport".
also, if you consider i and most megui users never had such a problem...
megui version? OS? program used for ripping the DVD? logfile?

*SIGH* I wasn't trying to be a jerk here... my apologies.

MeGUI version = 0.2.6.1049
OS = WinXP Pro SP2
Framework: 2.0. SP1

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Starting job job7 at 12:36:35 AM

Starting preprocessing of job...

Preprocessing finished!

successfully started encoding

Processing ended at 12:43:02 AM

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Log for job job7

Input: Channels=2, BitsPerSample=16, SampleRate=48000Hz
Command line used: C:\Program Files\megui\neroAacEnc.exe -ignorelength -cbr 192000 -if - -of "E:\New Folder\ea3to\audio_full.mp4"
*************************************************************
* *
* Nero Digital Audio Reference MPEG-4 & 3GPP Audio Encoder *
* Copyright 2007 Nero AG *
* All Rights Reserved Worldwide *
* *
* Package build date: Aug 6 2007 *
* Package version: 1.1.34.2 *
* *
* See -help for a complete list of available parameters. *
* *
*************************************************************




------------------------------------------------------

Starting postprocessing of job...

Postprocessing finished!

End of log for job7
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Processing ended at 12:47:53 AM

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After struggling last night, I manually converted the AC3 to WAV using EAC3TO and then to ACC using a similar ND-ACC command line as found in the log. When I mux this MP4 with the h264 stream, the video is in sync all the way through. I'm no expert and just learning (which is why I'm here trying to get some help from more experience users) but it seems more like an audio conversion thing than a muxing issue.

I didn't think I was pointing the finger at MeGUI... maybe there's a bug... likely not. I was assuming that it was operator error.

[Sharktooth]

ok, feed the wav (the one decoded bt eac3to) to megui as audio input and let megui do the rest of the job.
it it's in synch then the nic ac3 decoder (used by megui) has some problems.

[kartman_canada]

ok, feed the wav (the one decoded bt eac3to) to megui as audio input and let megui do the rest of the job.
it it's in synch then the nic ac3 decoder (used by megui) has some problems.

What is the ac3 decoder used by megui? I guess I was wondering if the issue is with a filter installed on my system as opposed to something within megui itself or with the tools/files distributed with it.

-THANX

[tebasuna51]

...
it it's in synch then the nic ac3 decoder (used by megui) has some problems.

Like I say before if "The AC3 file is 1:34:30 and the MP4 that MeGUI produces is exactly the same overall length.", NicAc3 decoder and NeroAacEnc works fine and can't do anymore.

[ash925]

Quote:
Could you expand on that, please? I'm having a similar problem with an mp2 to aac transcode.

Use besweet to convert the mp2 to wav and then from wav to aac.The direct transcode from wav to aac in besweet is not possible(the file I transcoded does not run on vlc).If you do not have besweet download it from internet you will also be needing aac.dll.