2 replies to this topic

[bearepj]

I want to make a music DVD from audio that is already compressed in mp3 format. If possible I would like to record this audio without further compression. Toast Help is a bit confusing on this point. It says "If the audio files are already compressed (such as MP3 or AAC songs in your iTunes library) do not use PCM - it will not improve the sound quality." Well, that's fine but would the PCM setting simply transfer the mp3 files "as is" so to speak? Wouldn't selecting Dolby Digital result in further compression and degredation of the sound quality of an mp3 file, and take a lot longer for encoding?

I realize that if the mp3 files are burned without further compression the capacity of the DVD would not be as great as if Dolby Digital were used, but I'm more concerned about quality. What I want to know is whether using the PCM setting would result, in effect, in just copying the mp3 files, as is, to the DVD. I still want to use the music DVD format to be able to include album art along with the sound.

[tsantee]

My understanding is that the PCM audio will sound no better than your MP3s. But re-encoding to Dolby Digital would result in some additional loss. If you chose a higher audio bit rate than the Toast default this loss will be less. Personally, my ears can't make the distinction. What has made an clear difference is using the DVD player's optical audio connection instead of its analog audio.

There is no way the MP3 (or AAC) files are copied without conversion.

[bearepj]

[quote name='tsantee' date='Sep 20 2006, 05:30 PM' post='53048']

Thanks tsantee. I tried selecting PCM and found that there would be a large size increase, by a factor of about six, something the help files don't make clear. I'm surprised Toast wouldn't have a setting to simply transfer files as is. Must have something to do with the fact that a Music DVD is really a video format with still pictures. I'll just use a high Dolby bit rate.