Thanks Jean-Marc and Steve for those comments. Yes fixed point is a lot of work that adds a whole new level of complexity. The code becomes harder to understand, and harder to maintain. In the current "state of the art" the abstractions available (like compiler extensions, functions macros etc to assist in expressing the porting) are of limited use - there is still lots of manual work and hard detail work to express and understand many intricate steps. It's difficult to delegate the work to people without very specialised skills.
It's a bit like deciding to re-write the codec in assembler, then mandating the C and assembler versions must be maintained side by side forever. However that does present an interesting challenge. Maybe there is a way to "engineer" or automate fixed point work so that it's more like "running a compiler" than hand crafting. - David On Sun, 2013-03-03 at 11:54 -0500, Jean-Marc Valin wrote: > I mainly see two issues with doing a fixed-point port of codec2: > > 1) It's hard to find people who can write a *good* fixed-point and in > general it's much harder for someone other than the original creator of > the algorithm to do the fixed-point. > > 2) Writing the fixed-point before the float is complete can be cause > maintenance headaches. Using dual fixed/float macros like I used for > Speex/Opus can help there, but it means it has to be done by the > original author or otherwise with very close communication (to avoid > breaking the fixed-point during development). > > Considering these, it doesn't seem to me like a good idea to go with a > fixed-point version of codec2 at this point unless there's overwhelming > demand for it. > > Jean-Marc > > On 13-03-02 03:22 PM, David Rowe wrote: > > Hello Samuel, > > > > Actually there are $3 32-bit microprocessors with floating point, and > > many embedded processors (e.g. those used in android phones) no have > > FPUs. So I think the need for fixed point is diminishing, its only a > > few thousand more transistors on a chip, Moores law etc. > > > > A year ago I worked up an estimate for the labour reqd for a fixed point > > port - it was about $80k. > > > > Cheers, > > > > David > > > > On Sat, 2013-03-02 at 09:01 +0000, Samuel Hunt wrote: > >> I can see turning Codec2 into Fixed point would have huge advantages for > >> opening up things like dsPIC devices, etc, and would be needed to take > >> Codec2 onto the next level. > >> > >> I have huge hopes for Codec2, but without it being possible to compile > >> it into a dsPIC or similar, it is somewhat limited to either having a > >> very expensive processor (relative to cheaper ones anyway!) or consigned > >> to somewhere where there is a PC. > >> > >> > >> What sort of money are we talking about, if the work is to be paid for? > >> > >> It would be interesting to list out all the areas which require > >> development. I notice a few listed on the website, generally relating to > >> quality, etc, but if money would help to accelerate these, it would be > >> nice to look at. > >> > >> > >> > >> Perhaps then we can find people to put the required money in to do > >> development in areas which most interest them? > >> > >> > >> Only a thought. > >> > >> Samuel Hunt > >> > >> > >> On 01/03/2013 21:30, freetel-codec2-requ...@lists.sourceforge.net wrote: > >>> Send Freetel-codec2 mailing list submissions to > >>> freetel-codec2@lists.sourceforge.net > >>> > >>> To subscribe or unsubscribe via the World Wide Web, visit > >>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > >>> or, via email, send a message with subject or body 'help' to > >>> freetel-codec2-requ...@lists.sourceforge.net > >>> > >>> You can reach the person managing the list at > >>> freetel-codec2-ow...@lists.sourceforge.net > >>> > >>> When replying, please edit your Subject line so it is more specific > >>> than "Re: Contents of Freetel-codec2 digest..." > >>> > >>> > >>> Today's Topics: > >>> > >>> 1. Re: Codec2 on asterisk is latest version? (David Rowe) > >>> 2. codec2 float to fixed ( ???? ) > >>> 3. Re: codec2 float to fixed (Bruce Perens) > >>> 4. Re: codec2 float to fixed (Andreas Weller) > >>> 5. Changing the Sample Rate (Daniel Mundall) > >>> 6. Re: Changing the Sample Rate (Bruce Perens) > >>> 7. Re: Changing the Sample Rate (Daniel Mundall) > >>> > >>> > >>> ---------------------------------------------------------------------- > >>> > >>> Message: 1 > >>> Date: Wed, 27 Feb 2013 06:16:27 +1030 > >>> From: David Rowe <da...@rowetel.com> > >>> Subject: Re: [Freetel-codec2] Codec2 on asterisk is latest version? > >>> To: freetel-codec2@lists.sourceforge.net > >>> Message-ID: <1361907987.3311.99.camel@bear> > >>> Content-Type: text/plain; charset="UTF-8" > >>> > >>> Hi Roberto, > >>> > >>> Nope, just the source code. I'd start by working towards getting two > >>> asterisk boxes to talk Codec 2. If you roll back your codec2-dev to the > >>> SVN version for which the Asterisk patches were generated it might work. > >>> > >>> - David > >>> > >>> On Tue, 2013-02-26 at 02:07 -0300, Roberto Carballa wrote: > >>>> Hi Bruce/David, > >>>> > >>>> > >>>> Thanks, for some reason I did not receive the digest. > >>>> Im not very used to do this, is there any guideline somewhere > >>>> on how to update the asterisk version? > >>>> > >>>> > >>>> Thanks, > >>>> Roberto > >>>> Bruce Perens Fri, 22 Feb 2013 16:35:36 -0800 > >>>> > >>>> > >>>> > >>>> In codec2-dev, not codec2. That could confuse people. > >>>> > >>>> Thanks > >>>> Bruce > >>>> > >>>> On 02/22/2013 04:33 PM, David Rowe wrote: > >>>>> Hello Robert, > >>>>> > >>>>> The latest version is what's in Codec 2 SVN. > >>>> > >>>> ------------------------------------------------------------------------------ > >>>> Everyone hates slow websites. So do we. > >>>> Make your web apps faster with AppDynamics > >>>> Download AppDynamics Lite for free today: > >>>> http://p.sf.net/sfu/appdyn_d2d_feb > >>>> _______________________________________________ Freetel-codec2 mailing > >>>> list Freetel-codec2@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > >>> > >>> > >>> > >>> > >>> ------------------------------ > >>> > >>> Message: 2 > >>> Date: Thu, 28 Feb 2013 14:05:06 +0800 > >>> From: " ???? " <496623...@qq.com> > >>> Subject: [Freetel-codec2] codec2 float to fixed > >>> To: " freetel-codec2 " <freetel-codec2@lists.sourceforge.net> > >>> Message-ID: <tencent_17b48fe44eaaef7632c86...@qq.com> > >>> Content-Type: text/plain; charset="gb18030" > >>> > >>> i recently compiled codec2 for a S3C2440 board,which has no fpu,the > >>> encode/decode speed is very slow. > >>> > >>> > >>> and i also planted speex on my board, > >>> when compiled without --enable-fixed-point,the encode/decode speed is > >>> very slow; > >>> but compiled with option --enable-fixed-point,the encode/decode speed is > >>> ok; > >>> > >>> > >>> so i wonder if codec2 has an --enable-fixed-point option when compile ; > >>> if codec2 doesn't has this option,what can i do ? go deep in the source > >>> code and convert the float to fixed?? that's difficult > >>> -------------- next part -------------- > >>> An HTML attachment was scrubbed... > >>> > >>> ------------------------------ > >>> > >>> Message: 3 > >>> Date: Wed, 27 Feb 2013 22:15:32 -0800 > >>> From: Bruce Perens <br...@perens.com> > >>> Subject: Re: [Freetel-codec2] codec2 float to fixed > >>> To: freetel-codec2@lists.sourceforge.net > >>> Message-ID: <9551d1c4-0538-4cc7-a0e9-c88d8abaf...@email.android.com> > >>> Content-Type: text/plain; charset="utf-8" > >>> > >>> Jean-Marc Valin created a set of macros that use float or fixed-point in > >>> Speex. We have not adapted Codec2 to use any form of fixed-point > >>> arithmetic yet. I think David would like to find someone to pay for the > >>> work. > >>> > >>> "????" <496623...@qq.com> wrote: > >>> > >>>> i recently compiled codec2 for a S3C2440 board,which has no fpu,the > >>>> encode/decode speed is very slow. > >>>> > >>>> > >>>> and i also planted speex on my board, > >>>> when compiled without --enable-fixed-point,the encode/decode speed is > >>>> very slow; > >>>> but compiled with option --enable-fixed-point,the encode/decode speed > >>>> is ok; > >>>> > >>>> > >>>> so i wonder if codec2 has an --enable-fixed-point option when compile ; > >>>> if codec2 doesn't has this option,what can i do ? go deep in the > >>>> source code and convert the float to fixed?? that's difficult > >>>> > >>>> ------------------------------------------------------------------------ > >>>> > >>>> ------------------------------------------------------------------------------ > >>>> Everyone hates slow websites. So do we. > >>>> Make your web apps faster with AppDynamics > >>>> Download AppDynamics Lite for free today: > >>>> http://p.sf.net/sfu/appdyn_d2d_feb > >>>> > >>>> ------------------------------------------------------------------------ > >>>> > >>>> _______________________________________________ > >>>> Freetel-codec2 mailing list > >>>> Freetel-codec2@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > >> > >> > >> > >> ------------------------------------------------------------------------------ > >> Everyone hates slow websites. So do we. > >> Make your web apps faster with AppDynamics > >> Download AppDynamics Lite for free today: > >> http://p.sf.net/sfu/appdyn_d2d_feb > >> _______________________________________________ > >> Freetel-codec2 mailing list > >> Freetel-codec2@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > > > > > > > ------------------------------------------------------------------------------ > > Everyone hates slow websites. So do we. > > Make your web apps faster with AppDynamics > > Download AppDynamics Lite for free today: > > http://p.sf.net/sfu/appdyn_d2d_feb > > _______________________________________________ > > Freetel-codec2 mailing list > > Freetel-codec2@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
