WAV to AC3 -- losing some volume

[MYoung]

Hey,

I'm authoring to DVD. I have a WAV that I'm converting to AC3 and muxing with my MPEG2. The problem is that I get much lower volume with the converted AC3. I'm using ffmpegGUI to convert the WAV to AC3. When I just use PCM audio with the DVD it's at the proper volume. How do I fix this if I want to use AC3 audio? Thanks!

[johns0]

You dont fix it,ac3 is meant to be that way.

[MYoung]

Why is that? Why doesn't AC3 as closely approximate the source PCM?

[wulf109]

The ac3 spec calls for the low volume level. When you play a DVD the ac3 audio plays at a much lower level than other audio sources,for example a VHS or cassttte player.
You might consider mpeg audio. It can play at "normal" levels and is compatible with most NTSC DVD players. Mpeg is a compressed audio format just as ac3 isa compressed audio format.

[Soapm]

Why is that? Why doesn't AC3 as closely approximate the source PCM?

You might want to take a gander at Somejoe's FAQ on AC3 audio. I thought it was very good reading and answered a lot of my questions.

[MYoung]

Thanks for the info and the URL.

I would do MPEG2 audio, but it just sounds like crap compared to the PCM. PCM audio is in the DVD spec, so how come some players don't support it? I'm torn, I want as much compatability as possible and I don't want the audio to sound lossy. I guess this still points me toward AC3 audio, eh?

[Soapm]

Thanks for the info and the URL.

I would do MPEG2 audio, but it just sounds like crap compared to the PCM. PCM audio is in the DVD spec, so how come some players don't support it? I'm torn, I want as much compatability as possible and I don't want the audio to sound lossy. I guess this still points me toward AC3 audio, eh?

Yep, I've gone all AC3 with my DVDr's and havn't looked back. The biggest thing I learned was how to normalize them and you won't have to play with the volume control while watching a movie.