ac3 -> aac gives file with split second of high pitch noise then nothing

[audioffile]

I'm using constant quality q=0.31 encoding ac3 2ch to aac. The output aac file has nothing but a split second of high pitch chirp like grasshoppers and then there's nothing.

there's no problem listening to the source ac3.

what is going wrong here? any ideas?

[tebasuna51]

what is going wrong here?

Maybe the method ?

(decoder -> encoder) ?

[audioffile]

Using ND AAC as the backend and MeGUI as the frontend. This was part of video encoding for the movie and now there's essentially no audio in this file. I wish I hadn't allowed MeGUI to delete the intermediate files.

[tebasuna51]

Maybe the original ac3 have problems (typical if came from video capture) not supported by NicAudio decoder used by Megui, try to fix the ac3 with DelayCut.

[audioffile]

thanks tebasuna.

i googled nicaudio and found a nicaudio bug report thread (http://forum.doom9.org/showthread.php?t=114968).

i wanted to try to find nicaudio so i could pass the ac3 file through it directly so i searched for nicaudio* and it didn't turn anything up. i downloaded it, but how could MeGUI be using nicaudio if the dll is not on my computer?

[mitsubishi]

audioffile, so have you sorted it?

BTW if you are searching windows, you have to check "search system folders" to find it, it will be in "C:\Program Files\AviSynth 2.5\plugins"

I see you've been cross posting and tried to "Force directshow decoding". But can you actually play an ac3 file through directshow? You need "ac3file" to do it, ac3filter cannot play a standalone file. http://ac3filter.net/projects/ac3file

You could also use "ac3tool", which uses azid to decode to wav and use those wav's.

In theory you can pipe azid to nero_aac like:

azid input.ac3 -Q -q - | neroaac.exe -if - -of output.mp4

But unfortunately that doesn't work because the resulting file is full of static, but I give the example anyway since you were asking about how meGUI pipes to nero without a wav file.

[audioffile]

@mitsubishi - actually, not cross posting... this is two different issues (at least i think it is). if you check out my log below for this track you'll see that neroaacenc did not throw an error, which makes me think it's a different problem.


Log for job job1

Input: Channels=2, BitsPerSample=16, SampleRate=48000Hz
Command line used: D:\Program Files\megui\tools\neroaacenc\win32\neroAacEnc_SSE.exe
-ignorelength -q 0.31 -if - -of "D:\DVDs\FRIDAY\VIDEO_TS\VTS_02_1 T01 2_0ch 192Kbps DELAY 0ms.m4a"
*************************************************************
* *
* 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. *
* *
*************************************************************

but thanks for the tip on how to search (feeling a little dumb) i should have known that one.

[audioffile]

:thanks: for your help everyone. I'm getting closer to figuring this one out. the input file must have some type of problem, although i'm not sure what. I tried converting it with BeHappy and it crashed BeHappy so I tried BeSweet and that program was finally successful, although I'm still really not sure why it works with one and not the other.

I checked in GSpot and tested rendering. All of the GSpot renders fail on quartz.dll.

- - Type DSH
- - Function Splitter
DSH 4CC MPEG1System
DSH Friendly Name MPEG-I Stream Splitter
DSH DirectShow CLSID CLSID_MPEG1Splitter {336475D0-942A-11CE-A870-00AA002FEAB5}
REG Driver File D:\WINDOWS\system32\quartz.dll
REG Merit 0x00600000


But they work on mpg2splt.ax, which eventually passes back to the quartz.dll for directsound output.

- - Type DSH
- - Function Splitter
DSH 4CC DOLBY_AC3
DSH Friendly Name AC3 Parser Filter
DSH DirectShow CLSID {280A3020-86CF-11D1-ABE6-00A0C905F375}
REG Driver File D:\WINDOWS\system32\mpg2splt.ax
REG Merit 0x00600000


So, I have it working for now, but it's always nice if someone can explain what happened. :)