Speex dev - Aug 2007 - Attempting to shrink speex: Are these functions necessary?

Hi,
 
I am using speex 1.2beta2 on a narrowband 16-bit, 8khz system that has
a severe program space problem and will not fit speex in its normal
operation.  In an attempt to shrink speex I placed a breakpoint in every
function and ran a decode and encode and removed the breakpoints that I
hit.  in the functions that had a breakpoint that I didn't hit I
commented out those functions (as well as some functions that I know I
won't hit).  
 
I am aware that some of these functions are only not called because I
don't do a GET_ in the ctl functions or don't use ALLOC to initialize
the bit buffer, but some of these I am not entirely sure why they would
or would not be used.  I would like to know if they are just rarely
called functions and that I could be breaking the codec by removing them
or if all that I removed is just fine.
 
I did get a .patch file from Jim Crichton as well to shrink nb_celp,
but is there anything else I can do to shrink the code or am I reaching
my limit? Thanks.
 
 
these are the functions that I removed:
 
In bits.c:
speex_bits_init
speex_bits_init_buffer
speex_bits_destroy
speex_bits_reset
speex_bits_rewind
speex_bits_read_from
speex_bits_flush
speex_bits_read_whole_bytes
speex_bits_write
speex_bits_write_whole_bytes
speex_bits_unpack_signed
speex_bits_peek_unsigned
speex_bits_peek
speex_bits_nbytes
speex_bits_insert_terminator
 
In cd_search.c:
noise_codebook_quant
noise_codebook_unquant
 
In filters.c:
compute_rms
syn_percep_zero16
qmf_decomp
qmf_synth
 
In ltp.c:
forced_pitch_quant
forced_pitch_unquant
 
In math_approx.c:
spx_ilog2
_spx_cos_pi_2
spx_cos_norm
spx_exp2
spx_atan
 
In nb_celp.c:
nb_encoder_destroy
nb_decoder_destroy
 
In quant_lsp.c:
lsp_quant_nb
lsp_unquant_nb
lsp_quant_high
lsp_unquant_high
 
In speex.c:
speex_encoder_destroy
speex_decoder_destroy
speex_encode
speex_decode
nb_mode_query
wb_mode_query
speex_lib_ctl
 
In speex_callbacks.c:
speex_inband_handler
speex_std_mode_request_handler
speex_std_low_mode_request_handler
speex_std_high_mode_request_handler
speex_std_vbr_request_handler
speex_std_enh_request_handler
speex_std_vbr_quality_request_handler
speex_std_char_handler
speex_default_user_handler
 
In vbr.c:
vbr_analysis
vbr_destroy
 
In vq.c:
vq_index
vq_nbest_sign
 
 
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> I am aware that some of these functions are only not called because I
> don't do a GET_ in the ctl functions or don't use ALLOC to
initialize
> the bit buffer, but some of these I am not entirely sure why they would
> or would not be used.  I would like to know if they are just rarely
> called functions and that I could be breaking the codec by removing them
> or if all that I removed is just fine.
Assuming you're not changing your code, there are very few functions
that would be "rarely called" (either it is every time, or it's
not).
The only exception might be the packet loss concealment function
(nb_decode_lost).
> these are the functions that I removed:
>  
> In bits.c:
> speex_bits_init
> speex_bits_init_buffer
> speex_bits_destroy
> speex_bits_reset
> speex_bits_rewind
> speex_bits_read_from
> speex_bits_flush
> speex_bits_read_whole_bytes
> speex_bits_write
> speex_bits_write_whole_bytes
> speex_bits_unpack_signed
> speex_bits_peek_unsigned
> speex_bits_peek
> speex_bits_nbytes
> speex_bits_insert_terminator
You probably don't need most of these, but I'm surprised you're not
at
least using speex_bits_init(), speex_bits_read_from() and
speex_bits_write(). What are you using instead?
> In cd_search.c:
> noise_codebook_quant
> noise_codebook_unquant
No need for that (assuming you only want 8 kbps).
> In filters.c:
> compute_rms
> syn_percep_zero16
> qmf_decomp
> qmf_synth
No need for that.
> In ltp.c:
> forced_pitch_quant
> forced_pitch_unquant
No need for that.
> In math_approx.c:
> spx_ilog2
> _spx_cos_pi_2
> spx_cos_norm
> spx_exp2
> spx_atan
No need for that.
> In nb_celp.c:
> nb_encoder_destroy
> nb_decoder_destroy
No need for that if you never plan on freeing the memory
> In quant_lsp.c:
> lsp_quant_nb
> lsp_unquant_nb
> lsp_quant_high
> lsp_unquant_high
No need for that if you just want 8 kbps.
> In speex.c:
> speex_encoder_destroy
> speex_decoder_destroy
> speex_encode
> speex_decode
> nb_mode_query
> wb_mode_query
> speex_lib_ctl
No need for that if you're not using them in your code.
> In speex_callbacks.c:
> speex_inband_handler
> speex_std_mode_request_handler
> speex_std_low_mode_request_handler
> speex_std_high_mode_request_handler
> speex_std_vbr_request_handler
> speex_std_enh_request_handler
> speex_std_vbr_quality_request_handler
> speex_std_char_handler
> speex_default_user_handler
No need for that.
> In vbr.c:
> vbr_analysis
> vbr_destroy
No need for that.
> In vq.c:
> vq_index
> vq_nbest_sign
No need for those.


So yes, there's a lot of stuff you can remove. You can also get rid of
the stereo preprocess, mdf files. You can also remove the VBR part of
the narrowband encoder and the vocoder part of the decoder. As I was
saying, there are very few codepaths that are only taken sometimes. So
unless a bit of code was executed in your test, it's very likely you
don't need it (packet loss concealment being the exception, because it's
only needed when you lose packets).

	Jean-Marc

Last thing. All the codebooks are stored as tables of char, so you're
probably wasting a lot of space from the fact that chars on C5x are
16-bit long. You might be able to pack the values in one 16-bit value
and unpack in the code. As for the memory allocation in the encoder, the
best is to use C99 variable-size arrays (VAR_ARRAYS) or alloca
(USE_ALLOCA). Otherwise, you can make the static array much smaller. For
8 kbps, the total RAM requirement (not counting code or static tables)
should be around 4 kB (2 kWords).

	Jean-Marc

Michael Jacobson a ?crit :
> Hi,
>  
> I am using speex 1.2beta2 on a narrowband 16-bit, 8khz system that has
> a severe program space problem and will not fit speex in its normal
> operation.  In an attempt to shrink speex I placed a breakpoint in every
> function and ran a decode and encode and removed the breakpoints that I
> hit.  in the functions that had a breakpoint that I didn't hit I
> commented out those functions (as well as some functions that I know I
> won't hit).  
>  
> I am aware that some of these functions are only not called because I
> don't do a GET_ in the ctl functions or don't use ALLOC to
initialize
> the bit buffer, but some of these I am not entirely sure why they would
> or would not be used.  I would like to know if they are just rarely
> called functions and that I could be breaking the codec by removing them
> or if all that I removed is just fine.
>  
> I did get a .patch file from Jim Crichton as well to shrink nb_celp,
> but is there anything else I can do to shrink the code or am I reaching
> my limit? Thanks.
>  
>  
> these are the functions that I removed:
>  
> In bits.c:
> speex_bits_init
> speex_bits_init_buffer
> speex_bits_destroy
> speex_bits_reset
> speex_bits_rewind
> speex_bits_read_from
> speex_bits_flush
> speex_bits_read_whole_bytes
> speex_bits_write
> speex_bits_write_whole_bytes
> speex_bits_unpack_signed
> speex_bits_peek_unsigned
> speex_bits_peek
> speex_bits_nbytes
> speex_bits_insert_terminator
>  
> In cd_search.c:
> noise_codebook_quant
> noise_codebook_unquant
>  
> In filters.c:
> compute_rms
> syn_percep_zero16
> qmf_decomp
> qmf_synth
>  
> In ltp.c:
> forced_pitch_quant
> forced_pitch_unquant
>  
> In math_approx.c:
> spx_ilog2
> _spx_cos_pi_2
> spx_cos_norm
> spx_exp2
> spx_atan
>  
> In nb_celp.c:
> nb_encoder_destroy
> nb_decoder_destroy
>  
> In quant_lsp.c:
> lsp_quant_nb
> lsp_unquant_nb
> lsp_quant_high
> lsp_unquant_high
>  
> In speex.c:
> speex_encoder_destroy
> speex_decoder_destroy
> speex_encode
> speex_decode
> nb_mode_query
> wb_mode_query
> speex_lib_ctl
>  
> In speex_callbacks.c:
> speex_inband_handler
> speex_std_mode_request_handler
> speex_std_low_mode_request_handler
> speex_std_high_mode_request_handler
> speex_std_vbr_request_handler
> speex_std_enh_request_handler
> speex_std_vbr_quality_request_handler
> speex_std_char_handler
> speex_default_user_handler
>  
> In vbr.c:
> vbr_analysis
> vbr_destroy
>  
> In vq.c:
> vq_index
> vq_nbest_sign
>  
>  
> 
> 
> 
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