On Wed, Dec 2, 2015 at 1:18 AM, Paul B Mahol <one...@gmail.com> wrote: > On 12/2/15, Ganesh Ajjanagadde <gajjanaga...@gmail.com> wrote: >> Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com> >> --- >> libavfilter/af_flanger.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/libavfilter/af_flanger.c b/libavfilter/af_flanger.c >> index f8ec830..a92367c 100644 >> --- a/libavfilter/af_flanger.c >> +++ b/libavfilter/af_flanger.c >> @@ -130,7 +130,7 @@ static int config_input(AVFilterLink *inlink) >> return AVERROR(ENOMEM); >> >> ff_generate_wave_table(s->wave_shape, AV_SAMPLE_FMT_FLT, s->lfo, >> s->lfo_length, >> - floor(s->delay_min * inlink->sample_rate + 0.5), >> + rint(s->delay_min * inlink->sample_rate), >> s->max_samples - 2., 3 * M_PI_2); >> >> return av_samples_alloc_array_and_samples(&s->delay_buffer, NULL, >> -- >> 2.6.2 >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> > > Have you checked that output is same?
Well if is not, rint is more accurate than floor, this is the whole point of the patch. What I can tell is that FATE passes. One can craft input so that floor(x + 0.5) is not identical to rint(x), and that is the point of these patches - to be more accurate when we can be. A simple example: what happens at half-integers, i.e 1.5? Then, floor always returns the next up, e.g 2.0, while rint(x) rounds to the nearest even integer in accord with IEEE-754. This is done to reduce rounding biases on floating point numbers - think of a large number of half integer samples, the floor hack results in consistent upward bias, the rint (or llrint, lrint more generally) avoids this. I care about technical purity of filters; you seem to care about copying it over from some other place and matching another filter exactly, regardless of the quality of such filters. In that case, I think FFmpeg's monolithic filter design needs to be reconsidered; we should allow seamless integration of external filters. These two goals are at odds with each other, and I will always personally prefer the first, since it actually allows greater flexibility for improvements. Ultimately, I am not a maintainer for these things and I have no say on the matter or personal interest in it. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
