Re: [music-dsp] Blend two audio
�
for me, the application would be in a time-domain time-scaling or
pitch-shifting alg where one is splicing out (for time-compression or
down-shifting) or splicing in (for time-stretching or up-shifting) extra
segments of audio that are short.� it's about what to do for the case
where the spliced audio is perfectly correlated or perfectly uncorrelated or
anywhere in between.
BTW, i took my 2014 post about this and posted it as an answer to a similar
question at StackExchange:
�https://dsp.stackexchange.com/questions/14754/equal-power-crossfade/49989#49989�
that might be more readable.
Original Message
Subject: Re: [music-dsp] Blend two audio
From: "Magnus Jonsson"
Date: Wed, June 20, 2018 6:55 pm
To: "robert bristow-johnson"
music-dsp@music.columbia.edu
--
> What kind of application is this for?
>
> On Wed, Jun 20, 2018 at 4:37 PM, robert bristow-johnson <
> r...@audioimagination.com> wrote:
>
>>
>>
>> okay, Benny, i am changing your "a(t)" to "x(t)", because i have been
>> using "a(t)" for the crossfade gain function.
>>
>> now if you want to splice from x(t) to x(t+T) when T is "estimated", does
>> that mean you can add or subtract a couple of milliseconds to T for the
>> purpose of minimizing the glitch that may result in the splice? i might
>> recommending doing that.
>>
>> so that, given an initial T, what i might recommend doing is evaluating
>> the cross-correlation between x(t) and x(t+T+tau)
>>
>> = integral{ x(t) x(t+T+tau) dt}
>>
>> where tau is a variable, either positive or negative and no larger than 5
>> or 10 milliseconds, that offsets T a little. look for the value of tau
>> that makes the cross-correlation maximum and adjust T with that value.
>>
>> then crossfade. whether it's an equal-voltage or equal-power crossfade is
>> something that the little "theory of optimal splicing" post is about.
>> someone brought up this 2016 DAFx paper by Marco Fink, Martin Holters, Udo
>> Z�lzer that appears to be about the same topic. i hadn't known about this
>> before so i am gonna be reading through it. it already appears that they
>> have an equation that is common with one from my post on music-dsp longer
>> ago. (i sorta wish they made a reference to it, but i am not sore about
>> it.)
>>
>> L8r,
>>
>> r b-j
>>
>> Original Message
>> Subject: Re: [music-dsp] Blend two audio
>>
From: "Benny Alexandar"
>> Date: Wed, June 20, 2018 1:11 pm
>> To: "Nigel Redmon"
>> "music-dsp@music.columbia.edu"
>> --
>>
>> > Hi Nigel,
>> >
>> > The delay will be estimated one time in the beginning and it remains
>> constant. After that the audio which is ahead is buffered for that much.
>> > When switching it has to align so that after switching to other audio,
>> it should be glitch free and seamless meaning user should not notice the
>> switching.
>> >
>> > For eg: two same audio sources one x(t) and other x(t + T) where T is
>> the delay between the two audio.
>> >
>> > -ben
>> >
>> >
>>
From: music-dsp-boun...@music.columbia.edu > columbia.edu> on behalf of Nigel Redmon
>> > Sent: Tuesday, June 19, 2018 4:44 AM
>> > To: music-dsp@music.columbia.edu
>> > Subject: Re: [music-dsp] Blend two audio
>> >
>> > Suggestions of crossfading techniques, but I’m not convinced that
>> > solves
>> the problem the OP posed:
>> >
>> > "given [two] identical audio inputs...A1 is ahead of A2 by t sec, when
>> switch from A1 to A2...it should be seamless”
>> >
>> > If the definition of “seamless” is glitch-free, crossfading
>> > will solve
>> it. But then why mention “identical" and “ahead”?
>> >
>> > I think he’s talking about synchronization. And it’s unclear
>> > whether t
>> is known.
>> >
>> >
>> > On Jun 16, 2018, at 10:45 AM, Benny Alexandar > > wrote:
>> >
>> > Hi,
>> >
>> > I'm looking for an algorithm to blend two audio. My requirement is
>> > given tow identical audio inputs say A1 & A2.
>> > A1 is ahead of A2 by t sec, when switch from A1 to A2
>> > it should be seamless and vice versa.
>> >
>> > -ben
>> >
>> > ___
>> > dupswapdrop: music-dsp mailing list
>> > music-dsp@music.columbia.edu
>> > https://lists.columbia.edu/mailman/listinfo/music-dsp
>>
>>
>>
>>
>>
>>
>>
>>
>> --
>>
>> r b-j r...@audioimagination.com
>>
>> "Imagination is more important than knowledge."
>>
>>
>>
>>
>>
>>
>>
>>
>> ___
>> dupswapdrop: music-dsp mailing list
>> music-dsp@music.columbia.edu
>> https://lists.columbia.edu/mailman/listinfo/music-dsp
>>
>
�
�
�
--
r b-j� � � � � � � � � � � �
Re: [music-dsp] Book: The Art of VA Filter Design 2.0.0alpha
> On Jun 18, 2018, at 2:08 AM, pa...@synth.net wrote: > > What Scott said, great resource thank you so much for sharing. > I'm still finding my way with VA stuff, so this will be invaluable. > > Paula (not on KvR) > > On 2018-06-11 13:33, Scott Gravenhorst wrote: >> Thank you so much for making this available. In fact, I'm currently >> involved in a project that >> needs this exact kind of information. >> -- ScottG >> music-dsp@music.columbia.edu wrote: >>> Hi everyone! >>> As usual, I'm duplicating here the announcement on KVR, since (I assume) >>> not everyone from this list is also present there. >>> The Art of VA Filter Design has been updated to 2.0.0alpha. Freely Thank you for this work! May I make a suggestion—do not use an acronym in the title. This might not be obscure to you but it might be obscure to someone who would otherwise benefit from your book. Jerry >>> available at this link: >>> https://www.native-instruments.com/fileadmin/ni_media/downloads/pdf/VAFilterDesign_2.0.0a.pdf >>> Major highlights compared to the previous release: >>> - different presentation of Sallen-Key filters >>> - 8-pole ladders >>> - detailed discussion of nonlinearities >>> - "Butterworth filters of the 2nd kind" >>> - different presentation of shelving filters, high-order generalized >>> Butterworth and elliptic shelving >>> - generalized Linkwitz-Riley crossovers >>> - lots of theoretical stuff >>> - last but not least: a neat formula for the frequency shifter's poles >>> The book is a mixture of new research, common knowledge (presented from >>> the POV of the author) and reinventing the wheel. I would be thankful >>> for pointers to previous research, which I might not be aware of. >>> Some of the new material is used in the soon to be released Reaktor Core >>> macro library update, so it can be tried out (and looked into) directly >>> there. >>> The book is in the "alpha" state, some of the material had only surface >>> checking and to an extent is a bit of a "work in progress". >>> Best regards, >>> Vadim >>> -- >>> Vadim Zavalishin >>> Reaktor Application Architect >>> Native Instruments GmbH >>> +49-30-611035-0 >>> www.native-instruments.com >>> ___ >>> dupswapdrop: music-dsp mailing list >>> music-dsp@music.columbia.edu >>> https://lists.columbia.edu/mailman/listinfo/music-dsp >> -- ScottG >> >> -- Scott Gravenhorst >> -- http://scott.joviansynth.com/ >> -- When the going gets tough, the tough use the command line. >> -- Matt 21:22 >> ___ >> dupswapdrop: music-dsp mailing list >> music-dsp@music.columbia.edu >> https://lists.columbia.edu/mailman/listinfo/music-dsp > ___ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp > ___ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Blend two audio
�
okay, Benny, i am changing your "a(t)" to "x(t)", because i have been using
"a(t)" for the crossfade gain function.
now if you want to splice from� x(t) to x(t+T) when T is "estimated", does that
mean you can add or subtract a couple
of milliseconds to T for the purpose of minimizing the glitch that may result
in the splice?� i might recommending doing that.
so that, given an initial T, what i might recommend doing is evaluating the
cross-correlation between x(t) and x(t+T+tau)
� �� = integral{�x(t) x(t+T+tau)� dt}
where tau is a variable, either positive or negative and no larger than 5 or 10
milliseconds, that offsets T a little.� look for the value of tau that makes
the cross-correlation maximum and adjust T
with that value.
then crossfade.� whether it's an equal-voltage or equal-power crossfade is
something that the little "theory of optimal splicing" post is about.� someone
brought up this 2016 DAFx paper by�Marco Fink, Martin Holters, Udo Z�lzer that
appears to be
about the same topic.� i hadn't known about this before so i am gonna be
reading through it.� it already appears that they have an equation that is
common with one from my post on music-dsp longer ago.� (i sorta wish they made
a reference to it, but i am not sore about
it.)
L8r,
r b-j
Original Message
Subject: Re: [music-dsp] Blend two audio
From: "Benny Alexandar"
Date: Wed, June 20, 2018 1:11 pm
To: "Nigel Redmon"
"music-dsp@music.columbia.edu"
--
> Hi Nigel,
>
> The delay will be estimated one time in the beginning and it remains
> constant. After that the audio which is ahead is buffered for that much.
> When switching it has to align so that after switching to other audio, it
> should be glitch free and seamless meaning user should not notice the
> switching.
>
> For eg: two same audio sources one x(t) and other x(t + T) where T is the
> delay between the two audio.
>
> -ben
>
>
From: music-dsp-boun...@music.columbia.edu
on behalf of Nigel Redmon
> Sent: Tuesday, June 19, 2018 4:44 AM
> To: music-dsp@music.columbia.edu
> Subject: Re: [music-dsp] Blend two audio
>
> Suggestions of crossfading techniques, but I’m not convinced that
> solves the problem the OP posed:
>
> "given [two] identical audio inputs...A1 is ahead of A2 by t sec, when switch
> from A1 to A2...it should be seamless”
>
> If the definition of “seamless” is glitch-free, crossfading will
> solve it. But then why mention “identical" and “ahead”?
>
> I think he’s talking about synchronization. And it’s unclear
> whether t is known.
>
>
> On Jun 16, 2018, at 10:45 AM, Benny Alexandar
> mailto:ben.a...@outlook.com>> wrote:
>
> Hi,
>
> I'm looking for an algorithm to blend two audio. My requirement is
> given tow identical audio inputs say A1 & A2.
> A1 is ahead of A2 by t sec, when switch from A1 to A2
> it should be seamless and vice versa.
>
> -ben
>
> ___
> dupswapdrop: music-dsp mailing list
> music-dsp@music.columbia.edu
> https://lists.columbia.edu/mailman/listinfo/music-dsp
�
�
�
--
r b-j� � � � � � � � � � � � �r...@audioimagination.com
"Imagination is more important than knowledge."
�
�
�
�
___
dupswapdrop: music-dsp mailing list
music-dsp@music.columbia.edu
https://lists.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Blend two audio
Hi Nigel, The delay will be estimated one time in the beginning and it remains constant. After that the audio which is ahead is buffered for that much. When switching it has to align so that after switching to other audio, it should be glitch free and seamless meaning user should not notice the switching. For eg: two same audio sources one a(t) and other a(t + T) where T is the delay between the two audio. -ben From: music-dsp-boun...@music.columbia.edu on behalf of Nigel Redmon Sent: Tuesday, June 19, 2018 4:44 AM To: music-dsp@music.columbia.edu Subject: Re: [music-dsp] Blend two audio Suggestions of crossfading techniques, but I’m not convinced that solves the problem the OP posed: "given [two] identical audio inputs...A1 is ahead of A2 by t sec, when switch from A1 to A2...it should be seamless” If the definition of “seamless” is glitch-free, crossfading will solve it. But then why mention “identical" and “ahead”? I think he’s talking about synchronization. And it’s unclear whether t is known. On Jun 16, 2018, at 10:45 AM, Benny Alexandar mailto:ben.a...@outlook.com>> wrote: Hi, I'm looking for an algorithm to blend two audio. My requirement is given tow identical audio inputs say A1 & A2. A1 is ahead of A2 by t sec, when switch from A1 to A2 it should be seamless and vice versa. -ben ___ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
