On Tue, 20 May 2008 15:14:00 -0700 Florin Andrei <florin@xxxxxxxxxxxxxxx> 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 _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
