Is it okay to go from AC3->MP3->AC3 again?

[surreal120]

This is probably a stupid question, but does anyone know if it's problematic to encode an AC3 to an MP3 and then back to AC3 for authoring on a DVD?

I did exactly that to reduce a director's commentary track down to 128kbps from 192kbps - sounded better with the mp3 intermediary step. Re-authored keeping exact dvd structure otherwise. In my standalone, the DVD plays fine UNLESS the director's commentary is turned on, in which case the movie plays for about a second and then freezes. (Everything works perfectly on my computer, however).

My only other thought is if low bitrates such as 128kbps audio is not supported on standalone players? Thanks!

[CaptainCarrot]

Usually I'd ask why you don't go from 192kbit AC3 -> 128 kbit AC3 in one step, but if you say it sounds better for you this way, why not. Can't see any playback problems arising from the intermidiate step.

[KpeX]

CaptainCarrot is correct, this will definitely not pose playback problems, although it is very strange IMO for the audio to sound better when encoding to MP3 intermediately, because in theory every transcode reduces quality. Although if it sounds good to your ears and speakers knock yourself out ;)

[surreal120]

Thanks for the help! Definitely did sound better this way; going straight to the lower bitrate AC3, there was very noticeable clipping in the voices. Sounded sort of like "Fred" - the Mac computer voice - on higher frequencies. Mp3 sounded much better. Go figure!

[Awatef]

What about AC3 -> WAV -> AC3?

Clipping has nothing to do with ac3 being the source.