AC3 Audio in MKV Not Converting

[KevinSartori]

Hello!  AVI2ISO is an excellent program, but I've run into a problem that I thought I should mention here.

I'm converting a 720p MKV w/AC3 audio.  The program runs nearly three hours and the original audio is 448kbps two-channel AC3.  To give a bit more bitrate to the video, I wanted the audio to be recoded to 224kbps.  Here are the settings I'm using with AVI2ISO 2.10.00 RC1:

Encoder:  CCE SP2 (4 Pass)
Max Bitrate: 9800
DVD (MB): 4400
DVD HIGH

Average bitrate is 3018, but increases to 3242 when I select 224 for audio bitrate.  After I hit "Start" (and then waited 10 hours) I ended up with a VIDEO_TS folder too big for a DVD-5.  In looking at the new encode, I realized that the video was encoded at the higher bitrate, but the audio remained at 448kbps.  I wasn't paying attention during the encode, so I don't know if it transcoded the 448kbps AC3 audio to 448kbps or if it just remuxed the original AC3 audio in without conversion.

To fix the problem, I used VOB2MPG to convert the new encode to MPG and then used Avanti to demux the MPG to M2V and AC3.  I then had Avanti recode the 448kbps AC3 to 224kbps AC3 and then used DVDAuthor GUI to re-author so I could burn it with Nero Burning ROM.  Whew!  Still, this was a lot quicker than running AVI2ISO again.

I've used AVI2ISO for quite a while now and have converted many MKV files and it's always performed well with no problems!  I've never asked it to recode the audio to a lower bitrate, though.  Has anyone else run into this problem?

Thanks for all of the effort you put into AVI2ISO!  It's the best DVD converter that I've run into!

[Delta]

  I wasn't paying attention during the encode, so I don't know if it transcoded the 448kbps AC3 audio to 448kbps or if it just remuxed the original AC3 audio in without conversion.

AVI2ISO doesn't reencode the audio if it is already in the DVD Standard AC3 format, it remains as it is

This behavior is due to the fact that almost all people wants a Quality Balanced DVD, i.e., the minimum quality loss of audio+video together, that's why AVI2ISO can preserve original DTS tracks as they are, without any loss

The only way to force a reencode with a new bitrate is to use the Normalize option, or for example converting DTS to AC3 when a warning popup window appears

To force audio conversion :

Select NORMALIZE option ( in audio TAB ) and audio will be reencoded at desired bitrate

You can keep the temporaries ( Special Options Tab ) and check what was made afterwards analyzing the temporary files

thanks for testing