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<DIV><FONT face=Arial size=2>Hi Sanjay,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2> According to the spec the max
code word length is 32 bits. As you have noted most of the time the code words
length is less than 24 bits. So if you are interested in saving memory you can
probably try having a run-time flag to represent whether a code book is
< 24 bit or not. So for code books less than 24 bits you can possibly use 24
bits. But i believe you still need to keep support for 32 bits as well, so that
when some bitstreams in current or future uses more than 24 bits your code can
still handle that.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Vinoth</FONT></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2> </FONT></DIV>
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style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A href="mailto:sanjaykumar.gupta@philips.com"
title=sanjaykumar.gupta@philips.com>Sanjaykumar Gupta</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A href="mailto:msmith@xiph.org"
title=msmith@xiph.org>Michael Smith</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A href="mailto:mlrsmith@gmail.com"
title=mlrsmith@gmail.com>mlrsmith@gmail.com</A> ; <A
href="mailto:tremor@xiph.org" title=tremor@xiph.org>tremor@xiph.org</A> ; <A
href="mailto:vorbis-bounces@xiph.org"
title=vorbis-bounces@xiph.org>vorbis-bounces@xiph.org</A> ; <A
href="mailto:vorbis@xiph.org" title=vorbis@xiph.org>Hibbs, Phil on
[vorbis]</A> ; <A href="mailto:tremor-bounces@xiph.org"
title=tremor-bounces@xiph.org>tremor-bounces@xiph.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, August 26, 2005 9:51
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Tremor] What can be the max
code word length in a code book?</DIV>
<DIV><BR></DIV><BR><FONT face=sans-serif size=2>Hi,</FONT> <BR><BR><FONT
face=sans-serif size=2>Thanks for the reply.</FONT> <BR><BR><FONT
face=sans-serif size=2>I have another important question wrt 24 bit platform
implementation of OggVorbis</FONT> <BR><BR><FONT face=sans-serif
size=2><B>What can be the max code word length in a code book?</B></FONT>
<BR><BR><FONT face=sans-serif size=2>In some cases, I have seen it is max 21
bits. Can it go beyond 24 bits? If it can occur, Can you suggest how to handle
it in 24bit platform as we don't have any variable type representing more than
24 bit.</FONT> <BR><BR><FONT face=sans-serif size=2>Please reply at your
earliest.</FONT> <BR><BR><FONT face=sans-serif size=2>Thanks.</FONT> <BR><FONT
face=sans-serif size=2><BR>Best
Regards,<BR>------------------------------------------------------------------------------------------------------------------------<BR>Sanjay
Kumar
Philips Innovation
Campus<BR>Technical Specialist
#1 Murphy Road<BR>Philips Applied
Technologies Ulsoor,
Bangalore - 560 008<BR>
Ph: +91 80 25579000 Extn. 5002<BR>
Fax: +91 80 25561283<BR>
Email: sanjaykumar.gupta@philips.com
<BR>------------------------------------------------------------------------------------------------------------------------<BR><BR></FONT><BR><BR><BR>
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<TD width="33%"><BR><BR><BR><BR><BR><FONT face=sans-serif
size=1><B>Michael Smith</B> </FONT>
<P><FONT face=sans-serif size=1>Sent by:</FONT> <BR><FONT
face=sans-serif size=1>mlrsmith@gmail.com</FONT>
<P><FONT face=sans-serif size=1>2005-08-25 03:07 PM</FONT> </P>
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<DIV align=right><FONT face=sans-serif size=1>To</FONT></DIV>
<TD vAlign=top><FONT face=sans-serif size=1>Sanjaykumar
Gupta/BTC/PDSL/PHILIPS@PHILIPS</FONT>
<TR>
<TD>
<DIV align=right><FONT face=sans-serif size=1>cc</FONT></DIV>
<TD vAlign=top><FONT face=sans-serif
size=1>tremor@xiph.org<BR>tremor-bounces@xiph.org<BR>"Hibbs, Phil
on [vorbis]"
<vorbis@xiph.org><BR>vorbis-bounces@xiph.org</FONT>
<TR>
<TD>
<DIV align=right><FONT face=sans-serif size=1>Subject</FONT></DIV>
<TD vAlign=top><FONT face=sans-serif size=1>Re: [Tremor] what is
max and min bitrate supported in OggVorbis?</FONT>
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<DIV align=right><FONT face=sans-serif
size=1>Classification</FONT></DIV>
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<DIV align=right><BR></DIV></TR></TBODY></TABLE><BR><BR><BR><FONT
size=2><TT>On 8/25/05, Sanjaykumar Gupta <sanjaykumar.gupta@philips.com>
wrote:<BR>> <BR>> Hi All, <BR>> <BR>> I am planning to
implement Ogg Vorbis Decoder on a 24 bit DSP. <BR>> <BR>> I have
following doubts: <BR>> <BR>> 1) What is min and max bitrate?
<BR><BR>Minimum bitrate is extremely low. Much less than one kilobit
per<BR>second. Maximum bitrate is not strictly bounded in the full
vorbis<BR>specification (we still hope to create a 'portable friendly
profile'<BR>in the future), but over 500 kbps is unusual.<BR><BR>>
<BR>> 2)What is max Audio Packet size ? <BR><BR>Not strictly bounded.
You can experiment with the reference encoder at<BR>very high bitrates to get
an idea of what real streams are likely to<BR>top out at.<BR><BR>>
<BR>> 3)What is the max size of setup header? <BR><BR>Can be large.
Several kilobytes is common. Perhaps a limit of 8 kB<BR>might be reasonable
for portable implementations?<BR><BR>> <BR>> 4)Any idea how to
start for making a 24Bit fixed point reference code? Shall<BR>> I start
with floating point or Tremor or Tremor Low Mem Version? <BR><BR>I'd say
tremor or tremor-lowmem, depending on whether you require<BR>particularly low
memory usage or not (note that -lowmem requires<BR>somewhat more
cpu).<BR><BR>> <BR>> 5) What window sizes in Ogg Vorbis are
normally supported for audio portable<BR>> player? <BR><BR>You should
ideally support all window sizes (i.e. from 64 to 8096).<BR>The smaller ones
(64 and 128) are pretty simple to deal with. 256,<BR>512, 2048, and 4096 are
all used by the reference encoder for common<BR>cases, so are absolutely
crucial. I think some encoders use 1024 as<BR>well. 8096 is something you
could skip if you don't have the memory<BR>available, but if you can fit it in
that would be preferable.<BR><BR>> <BR>> 6) Floor0 is termed to be
obsolete, Does this mean non of the commercially<BR>> available encoder
supports Floor0? <BR><BR>It's not obvious what you mean by "commercially
available". Certainly<BR>there were releases of the reference encoder (which
is by far the most<BR>commonly used one) which used floor0, and some people
have floor0<BR>files. However, later releases (including 1.0 and later) do not
use<BR>floor0, it's uncommon, and it's reasonable to remove support for it
if<BR>you have limited cpu power (it's significantly more cpu-intensive
than<BR>floor1).<BR><BR><BR>Mike<BR></TT></FONT><BR>
<P>
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