Help with all this digital stuff?

[M Holmes]

Paul Mather writes:

> I don't know about "non-geek" :-), but CD players ultimately work with
> 16-bit stereo samples @ 44.1 KHz sample rate.  MPEG audio (somewhat
> erroneously lumped into the grab-bag catch-all category of "MP3" in
> the popular mainstream) allows quite a bit of flexibility in encoding.
> Normally, though, it comes down to the bitrate you decide to use: the
> rate of MPEG data into which your original digital audio must be
> squeezed.  The lower the bitrate, the more quality you throw away to
> fit things in (but the smaller the resultant encoded file size).

OK, that makes sense. So what bitrate would give CD quality? The lowest
bitrate for MP3 seems to knock nearly 90% off the filesize. Presumably
that means the quality is quite poor? What do others use as the
reasonable compromise on portable players?

> Another important encoding setting is whether to use constant bitrate
> (CBR) or variable bitrate (VBR).  VBR is better, though CBR is older
> and hence likely to be universal.  VBR will dynamically alter the
> bitrate used on a frame-by-frame basis depending upon the complexity
> of the music.  So, "simple" things like "quiet bits" are encoded using
> a lower bitrate than "complex" things like "noisy whooshy bits." :-)

Yep, I can follow that :-)

> I have a Panasonic "walkman" that also supports "MP3" CD-ROM/R/RW
> discs.  It seems to accept VBR-encoded MPEG audio on a standard ISO
> 9660 disc.  I encoded about 7 hours of my Bevis Frond studio discs to
> provide a nice sample disc for when programming, and it will play it
> no bother.   I used the freeware "LAME" encoder encoding CDDA WAV files
> using VBR mode on high quality setting (128--320 kbps bitrate).  You
> can get a version of LAME for Windows.  EAC can even rip CDs to MPEG
> audio using LAME as the encoder.

EAC? It can do this on the fly?

> => Of course I'm then faced with 5 different recording formats for DVD
> => (only 5?). Anywhere I can find out about those?
>
> How about the DVD FAQ?  (http://www.dvddemystified.com/dvdfaq.html)

Looks good. I'll have a read of it.

> => flashcards much more quickly? However the HDD/DVD units that I've seen
> => seem to record in MP2 format rather than MP4. The Archos won't play MP2.
> => Am I likely to find a DVD/HDD which records in MP4 or is there some
> => reason why the companies won't do that?
>
> I'm guessing they'll be loathe to do that because MP2 is standard,
> whereas MP4 subjects you to to "codec hell."  The Archos is
> undoubtedly using MP4 so it can use a (possibly proprietary)
> high-compression codec to maximise the amount of video they can fit on
> the installed hard disc/flash card.

Ah. So the best I might be able to hope for is to plug in a flashcard to
the HDD/DVD recorder and transfer a movie (how fast are flashcards?
Would I get a whole movie on one? Do these thing allow editing where I
could split a whole move (MP2?) file into smaller files for transfer?)
to it; then plug the flashcard into the Archos and do a transfer; then
plug in the Archos as a portable drive on my computer and run an MP2 to
MP4 converter program (do these even exist?). Or would I be better just
recording a movie in realtime to the Archos?

FoFP