[speex-dev] Speex bitrate

[miguel.gomes]

I'm using speex to encode wav files. How does the --bitrate n option (use bit-rate n or lower) afects the quality and time of the encoding?
If I don't use that option how speex determines the bitrate to use in encoding?

Thanks in advance
 
Miguel Gomes

        -----Mensagem original----- 
        De: owner-speex-dev at xiph.org em nome de Chris Flerackers 
        Enviada: qui 18-03-2004 14:52 
        Para: speex-dev at xiph.org 
        Cc: 
        Assunto: Re: [speex-dev] denoise.c missing from 1.1.4 archive
        
        

        Hi,
        
        I was indeed using Visual C++ to compile speex.
        I made the following changes and now it compiles:
        - Remove denoise.c from project
        - Add jitter.c, lbr_48k_tables.c, lmdf.c, preprocess.c to project
        - Add the following to quant_lsp.c in the floating point case
            #ifndef M_PI
            #define M_PI           3.14159265358979323846  /* pi */
            #endif
        - Replace inline with __inline in lsp.c line 105
            static inline spx_word16_t spx_cos(spx_word16_t x)
        According to msdn: The inline keyword is available only in C++.
        The __inline and __forceinline keywords are available in both C and C++.
        
        When compiling in debug mode, I also get 530 warnings about double to
        float conversions. In release mode I don't get these warnings because the
        warning level is set to 1. Do these conversions impact performance? I think
        it is because you use e.g. 16000.0 instead of 16000.0f but I'm wondering
        if this causes computations to be done using doubles and then converted to
        float
        instead of working with floats all the time. If 32 bit float precision is
        enough, maybe
        it is better to use .0f everywhere?
        
        Best regards,
        Chris
        
        ----- Original Message -----
        From: "Jean-Marc Valin" <Jean-Marc.Valin at USherbrooke.ca>
        To: "speex" <speex-dev at xiph.org>; "Chris Flerackers"
        <cflerackers at androme.be>
        Sent: Wednesday, March 17, 2004 6:01 PM
        Subject: Re: [speex-dev] denoise.c missing from 1.1.4 archive
        
	> I just downloaded http://www.speex.org/download/speex-1.1.4.tar.gz and
	> tried to build it but the file denoise.c seems to be missing from the
	> archive.
	> Can you fix this or is it better to get everything from cvs?
        
        You're using Windows, right? The project file is simply out of date. The
        denoise.c file has been renamed to preprocess.c
        
	> Another question, when will a stable version of 1.1 be released. I'm
	> interested
	> in the preprocess features but I would also like a stable encoder/decoder
	> :-)
        
        So far, I'd say that the quality of 1.1.4 is probably higher than 1.0.3.
        It is considered unstable because I don't do the same amount of testing
        and I'm still changing many things. I think 1.2 (the next stable
        version) might take a couple months (can't be more precise). In the mean
        time, I'm considering back-porting the preprocessor to 1.0.x. I'll do
        that when I have time, but you can probably even do it yourself. All you
        have to do is change "short" for "float" at a couple places (or if
        you're lazy, the version in 1.1.1 might work directly).
        
         Jean-Marc
        
        --
        Jean-Marc Valin, M.Sc.A., ing. jr.
        LABORIUS (http://www.gel.usherb.ca/laborius)
        Université de Sherbrooke, Québec, Canada
        
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