Converting to AC3

[Adam]

Hi, I have tried to convert my PAL Nebula DigiTV .mpa files to AC3 files using both the TMPGEnc plug-in and BeSweet. Yet if I use the same bitrate as the mpa file, the file size is roughly the same. Am I missing something? Does AC3 allow you to lower the bitrate significantly without loss of quality? Any advice would be much appreciated.
Cheers,
Adam

[phd]

Hi Adam,

The usage of AC3 is for 2 reasons.

1. It will supposedly yield the same quality as MPEG audio at a little lower bitrate, saving some space. Relative to LPCM audio, it will only take up about 1/6 of the size. That's where the real savings occurs.

2. Compatibility with NTSC DVD players. Although I have not personally experienced this, supposedly NTSC players do not have to be compatible with MPEG audio.

[Adam]

Thank you Pat.

This makes sense, in essence it is ideally suited to compressing LPCM's not mpa's.

Thanks for making it clearer for me.

[Lester Burnham]

Hi, I have tried to convert my PAL Nebula DigiTV .mpa files to AC3 files using both the TMPGEnc plug-in and BeSweet. Yet if I use the same bitrate as the mpa file, the file size is roughly the same.



What were you expecting? File size is directly related to the bitrate.




Am I missing something? Does AC3 allow you to lower the bitrate significantly without loss of quality?



As a generalism, yes - but if you don't lower the bitrate, you won't see any (much) difference in file size.