[FFmpeg-devel] [PATCH] lavfi/af_sofalizer: remove exp2 and replace clz by ff_clz

[Paul B Mahol]

On 1/1/16, Ganesh Ajjanagadde <gajjanagadde at gmail.com> wrote:
> On Tue, Dec 29, 2015 at 1:17 PM, Ganesh Ajjanagadde
> <gajjanagadde at gmail.com> wrote:
>> ff_clz is faster, and uses an intrinsic (at the moment on GCC). exp2 is
>> a wasteful function for a simple integer exponentiation.
>>
>> Untested.
>>
>> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>> ---
>>  libavfilter/af_sofalizer.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavfilter/af_sofalizer.c b/libavfilter/af_sofalizer.c
>> index 6a24cbc..0bd1931 100644
>> --- a/libavfilter/af_sofalizer.c
>> +++ b/libavfilter/af_sofalizer.c
>> @@ -30,6 +30,7 @@
>>
>>  #include "libavcodec/avfft.h"
>>  #include "libavutil/float_dsp.h"
>> +#include "libavutil/intmath.h"
>>  #include "libavutil/opt.h"
>>  #include "avfilter.h"
>>  #include "internal.h"
>> @@ -996,8 +997,8 @@ static int config_input(AVFilterLink *inlink)
>>      }
>>      /* buffer length is longest IR plus max. delay -> next power of 2
>>         (32 - count leading zeros gives required exponent)  */
>> -    s->buffer_length = exp2(32 - clz((uint32_t)n_max));
>> -    s->n_fft         = exp2(32 - clz((uint32_t)(n_max +
>> inlink->sample_rate)));
>> +    s->buffer_length = 1 << (32 - ff_clz(n_max));
>> +    s->n_fft         = 1 << (32 - ff_clz(n_max + inlink->sample_rate));
>>
>>      if (s->type == FREQUENCY_DOMAIN) {
>>          av_fft_end(s->fft[0]);
>> --
>> 2.6.4
>>
>
> ping

OK if you remove dead code, clz() function.

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