AC3 Output

[Villain]

Just a simple question. I'm burning DVD to DVD-R and have D2S set to output AC3 files. However, once everything is done I find there are 2 AC3 files?

Extracted_audio_1.ac3

And

Encoded_audio_1.ac3

I'm guessing I use the Encoded_Audio file? I checked the file size and noticed they are slightly different. Compiled a project in SpruceUP with both and I can't really tell a difference. Just looking to know which is best to use, or if it even matters.

Ok, I just checked in DVDMaestro and it says the time for both is different as expected, but it says the .mpv file is different as well. The time doesn't match either of the AC3 files. What is that about?

[UltimateDBZ]

Use the encoded audio file.

[Villain]

Thanks :)

[kheops]

the log, in my example, says


--------------------------------------------------------
- 22/09/2003 12:47:24
- Free on drive D: 8336.89 mb
- AUDIO Extraction
--------------------------------------------------------
Found AC3 stream id: 0x81
Filename: D:\dvd2svcd\Extracted_audio_1.ac3
Audio1 delay: -80 ms
Framerate: 25000
Audio extraction finished.

--------------------------------------------------------
- 22/09/2003 12:53:49
- Free on drive D: 8336.89 mb
- AUDIO conversion
--------------------------------------------------------

Encoding Audio. Filename: D:\dvd2svcd\Extracted_audio_1.ac3
Executing BeSweet. Commandline:
"E:\utils\DVD2SVCD\BeSweet\BeSweet.exe" -core( -input "D:\dvd2svcd\Extracted_audio_1.ac3" -output "D:\dvd2svcd\Encoded_audio_1.ac3" -payload -logfile "D:\dvd2svcd\Encoded_audio_1.log" ) -ota( -d -80 )
Audio conversion of D:\dvd2svcd\Extracted_audio_1.ac3 finished.

Audio conversion finished.


besweet use azid then ac3enc to create the encoded file, this way afaik we can't say the ac3 is "untouched"

is there a reason why dvd2svcd (dvd2dvd for me) doesn't use ac3 delay corrector to shift frames ?

sorry if it sounds stupid

+

[jsoto]

Originally posted bt DSPGuru
in fact, mp2&ac3 positive/negative delay correction is also possible using the 'payload' mode of BeSweet v1.5

In -payload mode, BeSweet does not touch ac3/mp2 coding. It works in the same way than ac3delay corrector, cutting/adding complete frames
In previous betas there was a declared bug when correcting positive delays, but, currently, it is not in DSPGuru's open issues list, so it should be fixed (Even more, I've never seen a positive delay in a DVD)

Really, BeSweet is the most powerful audio tool I've seen. Thanks DSPGuru!

The question is if dvd2svcd is going to implement ac3 to ac3 transcoding (to save more bitrate for video), mainly because BeSweet supports it. I am sure he is thinking about it.

Cheers.

[kheops]

thanks a lot, if i have an hexadecimal look at both files, the (huge) end is strictly the same

let's say one file is
000111222333444555666777888999
the other one is
222333444555666777888999

this is a perfect result for me

:)

[jsoto]

If you are PAL users may be you can try mdvdauth plugin.
It supports ac3 to ac3 transcoding and uses IFOedit for authoring.

I am using my plugin for DVD authoring and it works fine for me (I do not have Scenarist...).

Cheers

[stevendm]

How do I set D2S to output ac3 audio files instead of mp2?

[jsoto]

In audio tab, check "Do not covert audio (use source audio)"
If I remember well, in some previous D2S releases this option was only available in Advanced mode (Misc tab), but not sure.
Please notice D2S does not support ac3 recoding, only delay adjustments.
jsoto