On Sat, Feb 01, 2020 at 06:06:39PM +0800, zhilizhao wrote: > > > > On Jan 27, 2020, at 6:28 PM, Zhao Zhili <quinkbl...@foxmail.com> wrote: > > > > > > > >> On Jan 27, 2020, at 12:59 AM, Carl Eugen Hoyos <ceffm...@gmail.com > >> <mailto:ceffm...@gmail.com>> wrote: > >> > >> Am So., 26. Jan. 2020 um 17:13 Uhr schrieb Zhao Zhili > >> <quinkbl...@foxmail.com <mailto:quinkbl...@foxmail.com>>: > >>> > >>> --- > >>> Or specify an upper limit on volume. What do you think? > >>> > >>> libavfilter/af_volume.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/libavfilter/af_volume.c b/libavfilter/af_volume.c > >>> index 213c57195a..029925cbfb 100644 > >>> --- a/libavfilter/af_volume.c > >>> +++ b/libavfilter/af_volume.c > >>> @@ -200,7 +200,7 @@ static inline void scale_samples_s16(uint8_t *dst, > >>> const uint8_t *src, > >>> int16_t *smp_dst = (int16_t *)dst; > >>> const int16_t *smp_src = (const int16_t *)src; > >>> for (i = 0; i < nb_samples; i++) > >>> - smp_dst[i] = av_clip_int16(((int64_t)smp_src[i] * volume + 128) > >>> >> 8); > >>> + smp_dst[i] = (int16_t)av_clip64(((int64_t)smp_src[i] * volume + > >>> 128) >> 8, INT16_MIN, INT16_MAX); > >> > >> The cast looks unnecessary and confusing but if a limit works, it is likely > >> simpler imo. > > > > The function is supposed to handle smp_src[i] * volume > INT32_MAX, so the > > cast is necessary. > > > > case AV_SAMPLE_FMT_S16: > > if (vol->volume_i < 0x10000) > > vol->scale_samples = scale_samples_s16_small; > > else > > vol->scale_samples = scale_samples_s16; > > break; > > > > I'm not sure about the use case. Does the function suppose to handle > > (((int64_t)smp_src[i] * volume + 128) >> 8) > INT32_MAX? > > > > By the way, there is another overflow in set_volume(): > > > > if (vol->precision == PRECISION_FIXED) { > > vol->volume_i = (int)(vol->volume * 256 + 0.5); > > vol->volume = vol->volume_i / 256.0; > > av_log(ctx, AV_LOG_VERBOSE, "volume_i:%d/255 ", vol->volume_i); > > } > > Ping. Any suggestions?
no but a question for the 64bit clip to make a difference the volume needs to be increased by like a factor of 65536. so everything will clip. Does this have a usecase ? or maybe iam missing something ? Thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Does the universe only have a finite lifespan? No, its going to go on forever, its just that you wont like living in it. -- Hiranya Peiri
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