[FFmpeg-devel] [PATCH]libavfilter/asrc_atone.c : generate algorithmic music

[Ashutosh Pradhan]

On Mon, Jun 29, 2020 at 6:53 PM Moritz Barsnick <barsnick at gmx.net> wrote:

> On Thu, Jun 25, 2020 at 21:15:06 +0530, Ashutosh Pradhan wrote:
> > Generate algorithmic riff music. Changed to activate api.
>
> This commit doesn't change to activate API, as it introduces this
> filter. So that sentence doesn't belong here.
>
> >  - Real War KVAG muxer
> > -
> > +- atone filter
>
> Don't remove the empty line.
>
> >    --enable-libflite        enable flite (voice synthesis) support via
> libflite [no]
> > +  --enable-libfluidsynth   enable libfluidsynth support for fluidsynth
> [no]
>
> "for fluidsynth"?. Perhaps "for atone source".
>
Will change to above.

>
> >  atempo_filter_select="rdft"
> > +atone_filter_deps="libfluidsynth"
>
> > + at item sfont
> > +Specify the location of soundfont file. Default value is
> > +"/usr/share/sounds/sf2/FluidR3_GM.sf2"(for linux).
>
> For Linux - and elsewhere?
> It will be the same path on all Unixes, but meaningless under Windows,
> I guess.
>
Yes.
Windows doesn't have the recommended Fluid_R3 General Midi SoundFont file.
So one has to enter the path every time.

>
> > +++ b/libavfilter/Makefile
> > @@ -152,6 +152,7 @@ OBJS-$(CONFIG_FLITE_FILTER)                  +=
> asrc_flite.o
> >  OBJS-$(CONFIG_HILBERT_FILTER)                += asrc_hilbert.o
> >  OBJS-$(CONFIG_SINC_FILTER)                   += asrc_sinc.o
> >  OBJS-$(CONFIG_SINE_FILTER)                   += asrc_sine.o
> > +OBJS-$(CONFIG_ATONE_FILTER)                  += asrc_atone.o
>
> I believe the audio sources are meant to be sorted alphabetically (by
> CONFIG_*).
>
> > --- a/libavfilter/allfilters.c
> > +++ b/libavfilter/allfilters.c
> > @@ -146,6 +146,7 @@ extern AVFilter ff_asrc_flite;
> >  extern AVFilter ff_asrc_hilbert;
> >  extern AVFilter ff_asrc_sinc;
> >  extern AVFilter ff_asrc_sine;
> > +extern AVFilter ff_asrc_atone;
>
> Same here.
>
> > +#include <float.h>
>
> > +    s->beat_dur = 60000/s->beats_pm;
> > +    /*get change interval in frames/sec*/
> > +    s->changerate = (4*s->beat_dur)*s->sample_rate/s->nb_samples;
> > +    if (s->changerate<1.0)
> > +        s->changerate = 1.0;
>
> Please leave single spaces around the operators such as '/', '*', '<'.
>
> > +    s->numriffs = sizeof(riff)/(NPR* sizeof(int));
>
> Same here.
>
> > +    for (int i = 0; i < s->numriffs*NPR ; i++)
>
> And here.
>
> > +    if (s->framecount == INT_MAX)
> > +       s->framecount = 0;
>
> Indentation.
>
> > +    for (int i = 0; i <
> sizeof(GM_instrument_list)/sizeof(GM_instrument_list[0]); i++)
>
> Use macro FF_ARRAY_ELEMS
>
> > +        if (strcmp(GM_instrument_list[i], instrument) == 0)
> > +            return i;
> > +
> > +    return 0;
> > +}
>
> If this doesn't match any string, it returns 0. It also returns 0 if it
> matches "Acoustic-Grand". Is that correct? (In find_percussion_track(),
> you return i instead.)
>
I didn't want to output an error incase the instrument did not match. I
forgot to update 0 with the number of the default instrument. I will update
that.

>
> > +static void schedule_noteon(int chan, short key, unsigned int ticks,
> int velocity, AtoneContext *s)
> > +{
> > +   fluid_event_t *ev = new_fluid_event();
>
> Indentation.
>
> > +    unsigned rand = av_lfg_get(&s->r)/2;
> [...]
> > +        riff = rand%s->numriffs;
>
> Spaces around operators, please.
>
> > +    if (3*i < numbars)
> > +        return (100 - (90*i)/numbars);
> > +    else if (3*i > 2*numbars)
> > +        return (40 + (90*i)/numbars);
>
> Same here.
>
> > +/*Determine the pattern, tempo (to paly as 8th, 16th or 32nd notes) and
> add the riffs to sequencer
>
> "play"
>
> > +Refernce: http://peterlangston.com/Papers/amc.pdf */
>
> "Reference"
>
> > +    AVFrame *frame;
> > +    int  nb_samples;
>           ^^ two spaces, drop one.
>
> > +    ret = ff_set_common_formats (ctx, formats);
>                                   ^ drop the space
>
> > +typedef struct
> > +{
>
> Bracket on the same line.
>
> > +Refernce: http://peterlangston.com/Papers/amc.pdf */
>
> "Reference".
>
>
> Regards,
> Moritz
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