Re: [LAU] DVD creator ?

On Tue, 20 May 2008 15:14:00 -0700
Florin Andrei <florin@email-addr-hidden> wrote:

> Dave Phillips wrote:
> >>
> > AVS lets me set the video width & height, so I'm okay there. Alas,
> > I can't set fractional frame rates, so 30 FPS is what I start with.
>
> Usually 30fps actually means 29.97, depending on the tool.
>
> > Audio output is a 48 kHz WAV, what considerations do I have where
> > that's concerned ?
>
> PCM can be used as an audio track on DVD, but it's a waste of space.
>
> Encoding to AC3 is trivial. The vast majority of commercial DVDs use
> that format for audio. Just use it, it's what everyone else does. :-)
> All my scripts encode the audio track to AC3, look there for
> inspiration.
>
> MP2 is the third option, but almost nobody uses it.
>
> > My current method of Kino-to-DVDStyler works, but the resulting
> > video is not good, definitely nowhere near as good as the original
> > AVI. I'll be investigating ways to improve the quality. I take it
> > that expensive higher-quality encoders are out there ?
>
> There are many possible reasons for the poor quality. The MPEG2
> encoder is the usual, but by no means the sole, suspect.
>
> If the source is noisy, it may overload the encoder. After all, there
> are only so many bits available in the video stream to encode the
> information. Reducing the input by denoising may help, provided that
> noise is indeed the problem.
>
> But yeah, often it's as easy as "use a better encoder". There are
> many professional encoders, quite expensive but quite good.
>
> HCenc is free and good enough. I did some tests with it, using
> commercial DVDs as a source, and re-encoded the material with HCenc,
> using mild compression. Even during a direct A/B comparison, I could
> not detect any quality loss.
> Also, when reducing the size of the video track, HCenc is equal to a
> good requantizer (like DVD Shrink) for small reduction factors (down
> to 70% of original track size); lower than that and HCenc becomes
> clearly better than any requantizer.
>
> That's kind of counter-intuitive, you would expect a full re-encoding
> to lose more quality than just shaving off bits with a requantizer,
> but the fact is that I tried several methods to put 3 hours of video
> on a single layer DVD and so far HCenc provided the best quality.
> It's also very good when the compression constraints are not so
> dramatic, but in that case many encoders are good enough.
>

Hi, I'm not into video, I'd just like to give possibly useful pointers.
When a discussion comes to audio codec quality, I usually point to
http://www.hydrogenaudio.org forums, where a lot of codec developers
hang out and doubleblind listening tests are performed. My
understanding is that http://www.doom9.org/ is a similar place for
video.
Hope it helps.

Best Regards,
        Philipp
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Received on Wed May 21 04:15:04 2008