File size growth ?

[stuft]

Can anybody out there help me?

I want to re-author a DVD I have. The DVD files I’ve ripped on my hard drive total 7.38GB but when I import them into Pinnacle 9 (without adding menus, chapters or anything else) it’s too big to burn to an 8.5 GB disk !!! The only change I’ve made is that the original audio was 5.1 and I’ve changed it to PCM (as I don’t have the 5.1 codec for Pinnacle).

I don’t want to compromise the video quality but I can live without the 5.1 sound setup if necessary. However, as it’s a music DVD I want to keep the audio as good as I possibly can with the tools I have at my disposal (hence my choice to use PCM as opposed to MPA MPEG-1 Layer 2 or Dolby(r) Digital 2-Channel). I could purchase the 5.1 codec Pinnacle but I don’t want to waste money if this won’t solve the problem. So does PCM require more disk space that 5.1 or is there some other reason why I cant get 7.4GB onto an 8.5GB disk?

[guns1inger]

The 5.1 AC3 audio probably 384, or at most, 448 kbps. PCM is uncompressed and requires 1536 kbps. So yes, it requires (a lot) more disc space.

Given it is already compressed, you really have nothing (or very, very little) to lose by converting it to AC3 2.0 @ 384 kbps. I doubt you will hear any difference.

[ZippyP.]

The 5.1 AC3 audio probably 384, or at most, 448 kbps. PCM is uncompressed and requires 1536 kbps.

So PCM is 3-5X bigger than AC3! (In case you couldn't do the math.)

[guns1inger]

For only 2 channels. Multichannel PCM is even larger

[stuft]

Thanks for the help and advise.

[bobkart]

Thanks for the help and advise.

Use an authoring tool that will let you retain the original AC3 (TDA for example). Uncompressing it to LPCM won't improve the quality, it will just take up more space for the same quality. And recompressing the LPCM back to AC3 is likely to degrade the quality even further than when it was first compressed to AC3.

EDIT: Now that I reread the quoted post I suspect you meant "advice". I read "advise" and did so.