Why PCM or Dolby Digital for NTSC DVD..

[seekninfo]

I read an article in which the writer made an assertion that at least one of the audio tracks on a NTSC DVD should either be PCM or Doby Digital. He did not offer any explanation which left a little bit confused as my understanding is that PCM for example is uncompressed and thus may take more space on the disc that could be used to improve the quality of the video.

Can someone please explain the basis of his statement ...

Thanks for any information.. I am still learning....

Seekninfo

[Cornucopia]

You have a choice of stream type based on your program needs.

When Audio is of prime importance (music videos, concert footage), LinearPCM can be used--no compression compromises, easy to decode, required to be (as per DVD decoder/player spec) universally acceptable.

When Video is of higher importance than audio (but audio is still somewhat important--most movies, tv shows, etc), compressed audio can be used--there is tradeoff between space savings (usable instead for video) and quality (low bitrate artifacts). Also there is a minor increase in decoder complexity (not really noticeable anymore).
AC3 is also required to be universally acceptable. MP2 and DTS usually acceptable, but not required as per the DVD spec, so not universal.

When Video is all important (and there is no need for audio), there is no audio track at all. This is also acceptable.

Depending on your needs, you need to choose at least one universally acceptable stream. If you want more than 1 audio stream, it may be of any type you like (of the 4 types).

For 5.1/surround audio, even though there is a theoretical allowance for PCM tracks, it is not really implemented in DVD players of any significance, so it the preferred option here is AC3.

Scott

[yoda313]

One additional note to cornucopia's excellent clarification. MP2 audio can be the sole audio track on an ntsc disc. My wintvpv250 records in mpeg only and mpeg audio. Any dvd player I've used plays the discs just fine. Though some of the old first generation dvd players may not like it. But these days mpeg audio only dvds will play just fine.

[Cornucopia]

True, but there's "DVD legal" and then there's "industry practice".

Example: JPEG/PhotoCD, MP3/WMA, MPG/DivX/WMV capability isn't "legal" by the DVD standard (well, yeah it is, since it's in the ROM/Other zone), but is certainly industry practice.

Better example: DVD+R/RW capability (in addition to legal DVD-R/W, DVD-ROM)

Doesn't really make a difference these days unless you require the ultimate in compatibility.

Scott

[seekninfo]

Thanks for the replies. They have really made the issue clearer for me. Thanks once again

[yoda313]

Doesn't really make a difference these days unless you require the ultimate in compatibility.

Of course the only way to gaurantee that is to get it commercially pressed (pricey ).

Glad to help seekninfo