encoding problem: WAV to AAC results in TRUNCATED file

[palmerac]

Has anyone experienced truncation problems when encoding AAC files (either CBR or VBR) from standard WAV files @44.1 kHz stereo using dMC R11? This is a real problem for me. It is especially noticeable with longer audio tracks that are 10 minutes in length or more -- the last few seconds of the encoded AAC audio is cut off, regardless of the bit rate or whether CBR or VBR encoding is selected. The same results occur with CBR encoding rates specified as 160 and 192, and VBR ~150 kbps (= Quality .45) and VBR ~200 (= Quality .55).

I downloaded and installed the most recent version of the Nero Digital encoder (v 1.0.7.0) from http://www.nero.com/nerodigital/eng/...tal_Audio.html but the problem persists.

Apple's AAC encoder (QuickTime or iTunes) does not seem to have this problem, but I don't think that Apple's encoder can be used with dMC.

Any advice or comments will be greatly appreciated.

[LtData]

Re: encoding problem: WAV to AAC results in TRUNCATED file

If you encode the WAV to AAC and then back to WAV, is it still shortened? Have you tried using dMC r12 or r11.5?

[palmerac]

Re: encoding problem: WAV to AAC results in TRUNCATED file

I'm using R11.5. Haven't yet upgraded to R12 since some codecs still aren't ready.

I just tried to convert the truncated .m4a file to .wav and the resulting .wav file is NOT truncated -- it is the proper length! Very interesting!

So it's as if the .m4a files encoded with NeroAACenc.exe have all of the audio data, but some is getting ignored so that the file does not play all the way to the end when played on RealPlayer, VLC Media player, or an iPod nano.

Is this a common problem?

[LtData]

Re: encoding problem: WAV to AAC results in TRUNCATED file

This problem has happened before but wasn't resolved. You might want to try a manual encoding test on a file to see if the problem lies with the Nero encoder .exe or within dMC somewhere.

Copy the NeroAACenc.exe and one of your wav files to C:\temp. Create the folder if it does not exist. Rename your WAV fie to a.wav. Then run the following in a command prompt window:

cd C:\temp
neroaacenc.exe -q .5 -ignorelength -if C:\temp\a.wav -of C:\temp\a.m4a
neroaacenc.exe -q .5 -ignorelength -hinttrack -if C:\temp\a.wav -of C:\temp\a2.m4a
neroaacenc.exe -q .5 -if C:\temp\a.wav -of C:\temp\a3.m4a

Now check to see if a.m4a and a2.m4a both play the full length.

Edit: also try a3.m4a

[Spoon]

Re: encoding problem: WAV to AAC results in TRUNCATED file

It would be interesting to try R12 and the latest nero encoder.

[palmerac]

Re: encoding problem: WAV to AAC results in TRUNCATED file

note to LtData: The switches -if and -of work fine, but using -ifile and -ofile does not work with this build. I'm using the new Feb 12 2007 build of NeroAACenc.exe, downloaded from Nero AG's website last week.

I will post a separate message with some interesting observations that I made while carrying out the test suggested above.

[LtData]

Re: encoding problem: WAV to AAC results in TRUNCATED file

palmerac: Whoops, changed them to -if and -of, thanks!

[palmerac]

Re: encoding problem: WAV to AAC results in TRUNCATED file

I did some testing with the command-line encoder, dMC R11.5, and Nero Wave Editor (v2.0.0.58) and I found that the problem seems to be with the NeroAACenc.exe encoder, not with dMC.

The specific problem: .wav files converted to .m4a using NeroAACenc.exe (with or without the -ignorelength and -hinttrack switches) do not play all the way to the end on my iPod nano or with RealPlayer v10.5 (w/ Harmony build 6.0.12). The same thing happens if I encode using dMC R11.5 (which relies on NeroAACenc.exe). But when I play these problematic files using QuickTime Player or VLC media player or FooBar2000, they play back correctly with the last few seconds intact -- nothing is missing! And if these same files are converted back to .wav using dMC, the entire audio track is there.

[SIZE=1]Example #1: When I convert a long .wav file that is 48:00 (48 minutes long) to .m4a using NeroAACenc and then right-click to use dbPOWERamp to check the tagged track time of the resulting .m4a file, the CORRECT TIME shows up. But if I open the same .m4a file with RealPlayer v10.5, the track time shows up as 47:33 and the last 27 seconds are cut off when I play the file with RealPlayer or on my iPod nano. Quicktime Player also displays the incorrect time (47:33), but plays the file all the way to the end (the counter goes beyond 47:33 despite the initial indication of the total track time)!

Example #2: When I convert a shorter .wav file that is 3:54 (three minutes and 54 seconds long) to .m4a using NeroAACenc, the track time shows up incorrectly as 3:52 in RealPlayer v10.5 and the last two seconds (approximately) are cut off when playing this file with RealPlayer or on my iPod nano. But it plays correctly with Foobar, etc.[/SIZE]

Interstingly, this problem does NOT occur when a .wav file is transcoded to .m4a (LC, VBR~195 Kbps) using Nero Wave Editor, which uses DLL codecs (AAC.dll v2.5.9.991 and AACenc32.dll v3.2.0.20) rather than the standalone .exe encoder that dMC uses. AAC files encoded with the Nero Wave Editor play correctly in RealPlayer and on my iPod nano, and the total track time displays correctly too.

So there must be some differences between Nero's DLL implementations and the .exe encoder. Apparently, NeroAACenc.exe writes file headers differently such that certain players miscalculate or mis-read the total length of encoded AAC files. Is anyone else aware of these differences?

[palmerac]

Re: encoding problem: WAV to AAC results in TRUNCATED file

If the R12 developers would like to implement some code that fixes .m4a files suffering from this problem then of course I would be thrilled, but that would be a 'band-aid' approach -- the more ideal solution would be to contact the Nero Audio developers and persuade them to FIX THIS BUG! Does anyone know how to contact the appropriate people at Nero AG?

I'm using the new Feb 12 2007 build of NeroAACenc.exe, downloaded from Nero AG's website last week, so this problem obviously was not fixed for the Feb 12 2007 release.

[Spoon]

Re: encoding problem: WAV to AAC results in TRUNCATED file

Have you tried the m4a optimize utility codec? on those files?

[palmerac]

Re: encoding problem: WAV to AAC results in TRUNCATED playback

Well I finally got around to installing a trial version of dMC R12 today, as well as the R12 codecs and the AAC optimizer. But I still have the same playback problem on my iPod Nano (first gen Nano).

WAV files converted to AAC (.m4a) using dMC and NeroAACenc don't play all the way through on an iPod -- the last few seconds get cut off, even after running the AAC optimizer (R1) on the resulting .m4a file.

I have read elsewhere that this is an iPod-specific problem. Is there a work-around or other solution? Should I try the latest beta version of the AAC encoder?

[LtData]

Re: encoding problem: WAV to AAC results in TRUNCATED playback

Try the latest beta m4a encoder and see if it still happens.

[Spoon]

Re: encoding problem: WAV to AAC results in TRUNCATED playback

Which program is uploading to your iPod, the ipod takes the length from the uploading program.

[palmerac]

Re: encoding problem: WAV to AAC results in TRUNCATED file

I usually use Anapod when uploading music to an iPod. Is there another piece of software that does a better job of passing the timing info to iPods?