| Message ID | 20171202174659.1064-4-modchipv12@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
On 2 December 2017 at 17:46, Andrew D'Addesio <modchipv12@gmail.com> wrote: > When decoding to downmixed mono, don't put the channels out of phase, > as they will cancel out and create audible artifacts. (See > RFC 8251 sec. 10.) > > Signed-off-by: Andrew D'Addesio <modchipv12@gmail.com> > --- > libavcodec/opus_pvq.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/libavcodec/opus_pvq.c b/libavcodec/opus_pvq.c > index 2f7aa74..f18c010 100644 > --- a/libavcodec/opus_pvq.c > +++ b/libavcodec/opus_pvq.c > @@ -643,7 +643,13 @@ static av_always_inline uint32_t > quant_band_template(CeltPVQ *pvq, CeltFrame *f, > } > } else { > inv = (b > 2 << 3 && f->remaining2 > 2 << 3) ? > ff_opus_rc_dec_log(rc, 2) : 0; > + > + /* Don't put the channels out of phase if we are decoding > to downmixed > + * mono as this subjectively sounds bad (RFC 8251 section > 10). */ > + if (f->channels == 1) > + inv = 0; > } > + > itheta = 0; > } > qalloc = opus_rc_tell_frac(rc) - tell; > -- > 2.15.1.windows.2 > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > RFC8251 made this optional, pushed a new version which added an option to toggle this.
On 12/4/2017 4:39 AM, Rostislav Pehlivanov wrote: > On 2 December 2017 at 17:46, Andrew D'Addesio <modchipv12@gmail.com> wrote: > >> When decoding to downmixed mono, don't put the channels out of phase, >> as they will cancel out and create audible artifacts. (See >> RFC 8251 sec. 10.) >> >> Signed-off-by: Andrew D'Addesio <modchipv12@gmail.com> >> --- >> libavcodec/opus_pvq.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/libavcodec/opus_pvq.c b/libavcodec/opus_pvq.c >> index 2f7aa74..f18c010 100644 >> --- a/libavcodec/opus_pvq.c >> +++ b/libavcodec/opus_pvq.c >> @@ -643,7 +643,13 @@ static av_always_inline uint32_t >> quant_band_template(CeltPVQ *pvq, CeltFrame *f, >> } >> } else { >> inv = (b > 2 << 3 && f->remaining2 > 2 << 3) ? >> ff_opus_rc_dec_log(rc, 2) : 0; >> + >> + /* Don't put the channels out of phase if we are decoding >> to downmixed >> + * mono as this subjectively sounds bad (RFC 8251 section >> 10). */ >> + if (f->channels == 1) >> + inv = 0; >> } >> + >> itheta = 0; >> } >> qalloc = opus_rc_tell_frac(rc) - tell; >> -- >> 2.15.1.windows.2 >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> > > RFC8251 made this optional, pushed a new version which added an option to > toggle this. Valgrind complains about your changes in 1b8649c2ce. Conditional jump or move depends on uninitialised value(s). http://fate.ffmpeg.org/report.cgi?time=20171204200723&slot=x86_64-archlinux-gcc-valgrind
diff --git a/libavcodec/opus_pvq.c b/libavcodec/opus_pvq.c index 2f7aa74..f18c010 100644 --- a/libavcodec/opus_pvq.c +++ b/libavcodec/opus_pvq.c @@ -643,7 +643,13 @@ static av_always_inline uint32_t quant_band_template(CeltPVQ *pvq, CeltFrame *f, } } else { inv = (b > 2 << 3 && f->remaining2 > 2 << 3) ? ff_opus_rc_dec_log(rc, 2) : 0; + + /* Don't put the channels out of phase if we are decoding to downmixed + * mono as this subjectively sounds bad (RFC 8251 section 10). */ + if (f->channels == 1) + inv = 0; } + itheta = 0; } qalloc = opus_rc_tell_frac(rc) - tell;
When decoding to downmixed mono, don't put the channels out of phase, as they will cancel out and create audible artifacts. (See RFC 8251 sec. 10.) Signed-off-by: Andrew D'Addesio <modchipv12@gmail.com> --- libavcodec/opus_pvq.c | 6 ++++++ 1 file changed, 6 insertions(+)