[Speex-dev] ogg files with spx and tagging

[Pierre Marc Dumuid]

Dear Developers,

I am currently involved in the co-ordination of archiving a whole heap
of tapes containing audio (4000+ sermons for www.newcreation.org.au) to
digital format.
At present, all the tapes have been converted into mp3 @ CBR 40kbs,
44100 Hz... And this appears to play in most portable players capable of
playing mp3's.  (ogg vorbis isn't that widely supported, and many
portable players don't like frequencies other than 44100 Hz, or bitrates
lower than 40 kbs)

I am interested in converting these mp3's into spex format to reduce the
file size so that these tapes can be downloaded much more easilier over
the internet.  For the how-to's for the users, I am primarily interested
encouraging users to use Winamp for windows, and XMMS for linux... (I
don't know what to recomment for Macintosh)

On of the primary concerns is that I am able to edit the title, author,
album, and comment information for the file.  The manual states that
"/Speex bit-streams can be stored in Ogg files./"  Thus I assume that it
is possible to encode speex as either ".spx" or ".ogg"

At the moment, I am assuming that there are many tag editors for the ogg
format, and none for the .spx format.  A quick look at the hexdump of a
.spx file starts with:

[pmdumuid at Andottie speex-xmms]$ hexdump -C ~/male.spx  | more
00000000  4f 67 67 53 00 02 00 00  00 00 00 00 00 00 c6 f2
|OggS............|
00000010  89 01 00 00 00 00 28 db  bf 85 01 50 53 70 65 65
|......(....PSpee|
00000020  78 20 20 20 31 2e 30 2e  33 00 00 00 00 00 00 00  |x
1.0.3.......|
00000030  00 00 00 00 00 00 00 00  01 00 00 00 50 00 00 00
|............P...|
00000040  40 1f 00 00 00 00 00 00  04 00 00 00 01 00 00 00
|@...............|
00000050  ff ff ff ff a0 00 00 00  00 00 00 00 01 00 00 00
|................|
00000060  00 00 00 00 00 00 00 00  00 00 00 00 4f 67 67 53
|............OggS|
00000070  00 00 00 00 00 00 00 00  00 00 c6 f2 89 01 01 00
|................|
00000080  00 00 85 a7 12 f5 01 35  18 00 00 00 45 6e 63 6f
|.......5....Enco|
00000090  64 65 64 20 77 69 74 68  20 53 70 65 65 78 20 31  |ded with
Speex 1|
000000a0  2e 30 2e 33 01 00 00 00  11 00 00 00 74 69 74 6c
|.0.3........titl|
000000b0  65 3d 68 65 6c 6c 6f 20  74 68 65 72 65 4f 67 67  |e=hello
thereOgg|
000000c0  53 00 00 80 43 00 00 00  00 00 00 c6 f2 89 01 02
|S...C...........|
000000d0  00 00 00 a6 b2 6b 09 6c  26 26 26 26 26 26 26 26
|.....k.l&&&&&&&&|
000000e0  26 26 26 26 26 26 26 26  26 26 26 26 26 26 26 26
|&&&&&&&&&&&&&&&&|
*
00000140  26 26 26 26 2d dd 10 17  a4 00 00 ff ff ff ff ff
|&&&&-...........|


With seeing the "OggS" and "Speex" strings, I get the feeling .spx files
may just be .ogg files.  Is this the case?  If this is the case then
maybe the sentence in the manual should be rewritten as: /"Speex
bit-streams *ARE* be stored in Ogg files."/

Anyhow, my questions are:

* How do I encode speex as ogg files, and if I do:
* Do the spex plugins work with both .spx files and .ogg files, or
is a special .ogg plugin required that includes a speex decoder?

At the moment it appears I may be able to rename the spx files to .ogg,
then edit the tags using a standard ogg tag editor, then rename the
files back to .spx.  Is this O.K??

Regards,
Pierre Dumuid
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