On Wed, Dec 30, 2015 at 1:01 AM, Hendrik Leppkes <h.lepp...@gmail.com> wrote:
> On Wed, Dec 30, 2015 at 4:39 AM, Ganesh Ajjanagadde
> <gajjanaga...@gmail.com> wrote:
>> The log is anyway rounded to an integer, so one may use an frexp
>> based approach. Note that this may be made frexpf; if arguments are less than
>> 2^24 there is no loss. Kept as double precision for simplicity; 2^32 is
>> exactly representable as a double.
>>
>> Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com>
>> ---
>> ffmpeg.c | 13 ++++++++++++-
>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/ffmpeg.c b/ffmpeg.c
>> index 6d01987..ee72f91 100644
>> --- a/ffmpeg.c
>> +++ b/ffmpeg.c
>> @@ -1486,6 +1486,17 @@ static void print_final_stats(int64_t total_size)
>> }
>> }
>>
>> +static inline int log2i(double d)
>> +{
>> + int exp;
>> + double mant;
>> +
>> + mant = frexp(d, &exp);
>> + if (mant >= M_SQRT1_2)
>> + return exp;
>> + return exp-1;
>> +}
>> +
>> static void print_report(int is_last_report, int64_t timer_start, int64_t
>> cur_time)
>> {
>> char buf[1024];
>> @@ -1559,7 +1570,7 @@ static void print_report(int is_last_report, int64_t
>> timer_start, int64_t cur_ti
>> if (qp >= 0 && qp < FF_ARRAY_ELEMS(qp_histogram))
>> qp_histogram[qp]++;
>> for (j = 0; j < 32; j++)
>> - snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
>> "%X", (int)lrintf(log2(qp_histogram[j] + 1)));
>> + snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
>> "%X", log2i(qp_histogram[j] + 1));
>> }
>>
>> if ((enc->flags & AV_CODEC_FLAG_PSNR) && (ost->pict_type !=
>> AV_PICTURE_TYPE_NONE || is_last_report)) {
>> --
>> 2.6.4
>
> This isn't exactly a performance critical area, and defining a custom
> function just for this seems somewhat like over-optimization.
> Just my opinion, of course, I'll leave the decision up to the
> maintainers of ffmpeg.c
Ping: based on the above, final decision left to you, Michael.
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