taking many 198k mp3 files and converting them to 16k mp3

[Gary Kline]

On Mon, Aug 28, 2006 at 01:56:31PM +0100, Howard Jones wrote:
> Gary Kline wrote:
> > 	Well, if/when you *do* try, please clue me in.  --I'm too new to
> > 	DVD's and tooo che--er, thrifty to buy a ten pack of blanks.  I'm
> > 	not sure that I have three hours of "favorites"; probably, but no
> > 	more.  Most of my favorite tunes are on tape--pre-recorded and
> > 	hi-fidelity, but the problem is turnning analogue to digital. 
> 
> Thrift isn't really an issue nowadays - you can get 50 DVD-Rs for about
> $10-15 online. Cheap enough to use a few to experiement, in my opinion.

	Wow! that really *is* a deal.  About where the floppies were
	years back.   I was guessing $2.50+ per blank.

> 
> I did some experimenting last night, and got what seems to be a working
> solution. I don't have a DVD burner where I am, so I haven't *actually*
> burned one, but 2 software players (Apple's and Media Player Classic)
> are both happy with the VIDEO_TS files. From my brief research, the
> minimum bitrate for DVD audio is 32Khz, and there isn't a minimum for
> the video, only a maximum. There is also a video-CD-like frame size of
> 352x480 for NTSC so you can reduced the video size further.
> 
> For my test audio file (2:12 song), I got:
> 2.2MB Original MP3 file - 192Kbit/sec 44.1Khz sample-rate joint stereo
> 3.3MB MP2 file - no changes apart from 44.1->48 resampling
> 0.5MB MP2 file - resampled to 48Khz, forced to mono and 32Kbit/sec
> output stream
> 
> the 0.5MB file doesn't actually sound *that* bad for music - it's AM
> radio quality. It would be fine for speech.
> 
> A 64Kbps video file to go with it is about 2.6MB, so the final 'DVD
> file' is either 6.7M ('music' quality) or 4M ('voice' quality). DVD
> authoring adds around 800K, but I don't believe this is per-chapter.
> 
> Assuming that it isn't, that's around 2400 minutes on a DVD-R (voice) or
> 1500 minutes (music), and it should be playable on any DVD player, since
> it should be a full-spec DVD still.


	Video is a just-say-no in my case; I've got around 26 hours of
	very high quality (192K) mp3 files (voice) that ought to be just
	fine at 32K/48KHz monaural.   This for the stuff that's taking up
	hundreds of megs on-disk.

	As for collecting my favorite, I don't have anywhere near 25
	hours (1500 minutes) of them, so maybe I'll  wait until "mp4"
	or "AACplus"  [[[ these are the same, right? ]]] is more widely
	available, then stuff my few hours onto a regular CD-R.  

> 
> Here's my notes on producing a disc. This is for an NTSC disc. For PAL,
> you need to change 480 to 576 wherever it appears, add 'pal' instead of
> 'ntsc' to the dvdauthor line, and "-f 25" instead of "-f 30" in the
> transcode line.
> 
> I'm no video expert, so I'm sure there are better ways to do this, but
> this one worked for me!

	
	Well sir, you are lightyears beyond me!!  During my hackery years
	I worked mostly in the supercomputer realm.   Sound? video? on
	a *computer*???   Faugh!  

	I'm finally learning what I was missing :-)

	thanks much for your help.  same for everybody else who
	offered help, clues, and code!

	gary

> 
> Howie
> 
> ######################################################################################
> # Take the MP3 file, play it into toolame as 48Khz PCM data
> # toolame reencodes as MP2 (for DVD) at 32khz (the minimum?) in mono
> madplay -R48000 -b16 -o wave:- mytestfile.mp3 | toolame -s 48 -b 32 -a
> -m m - mytestfile.mp2
> # (take out the -b 32 and -a -m m if you want music quality)
> 
> # next, we'll produce a VERY low bitrate MPEG2 movie of the same length as
> # the audio  since we have to do *some* encoding here, we might as well make
> # the static image be the title of the audio track.
> 
> # this is ALL ONE pipeline
> ppmmake blue 352 480 | \
> ppmlabel -x 50 -y 100 -text "This is the track name" | \
> ppmtoy4m -S 420mpeg2 -r -v2 | \
> transcode -x yuv4mpeg,mp3 -y mpeg2enc,null -o mytestfile -p
> "mytestfile.mp3" \
>     -Z 352x480 -F "8,-b 64" -i /dev/stdin -g 352x480 --import_asr 2 -f
> 30 -m /dev/null
> 
> # So that's: make a blank blue image of the correct size for NTSC video
> at the smallest size
> # add a caption over it
> # take that PPM file use it to stream frames into the video transcoder.
> #  (We only have one frame, so just repeat it)
> # transcode takes that frame and encodes it as DVD-compatible 64kbps MPEG-2
> # (normally for a DVD movie it would be more like 5000kpbs)
> # we import an audio stream even though we aren't using it, so as to get
> the
> # right length. Otherwise we get a never-ending video stream :-)
> 
> # So now, there's a .m2v video stream, and a .mp2 audio stream, and we
> need to
> # multiplex them.
> mplex -f 8  -o mytestfile.mpg  mytestfile.m2v mytestfile.mp2
> 
> # *** repeat the above for each of your audio files. ***
> 
> # finally, we can make a simple DVD
> dvdauthor -v ntsc+4:3+352x480 -a mp2+en+1ch+16bps -t -o testdvd
> mytestfile.mpg
> dvdauthor -T -o testdvd
> 
> # if you used 'music' quality encoding in toolame, then use 2ch instead
> of 1ch here
> 
> # You should find a DVD structure (VIDEO_TS, AUDIO_TS) waiting in the
> 'testdvd' directory.
> # you can specify multiple .mpg files on the command line, and each one
> will
> #    become a chapter on the DVD
> 
> # FINALLY, to get a burnable ISO image:
> mkisofs -dvd-video -o testdvd.iso testdvd
> # and burn it to /dev/acd0:
> growisofs -dvd-compat -Z /dev/acd0=testdvd.iso
> 
> # Ports used:
> #  sysutils/dvd+rw-tools  (growisofs)
> #  sysutils/cdrtools (mkisofs - installed as a dependency of dvd+rw-tools)
> #  mjpegtools  (mplex, y4m stuff)
> #  netpbm    (ppmfile, ppmlabel)
> #  toolame   (MPEG Layer II encoding)
> #  madplay   (MP3 decoding)
> #  dvdauthor (final authoring)
> #  transcode (install this last, so it gets the mpeg2encode from mjpegtools)

-- 
   Gary Kline     kline at thought.org   www.thought.org     Public service Unix