[FFmpeg-devel] [PATCH] swresample/swresample: check for invalid sample rates

[Michael Niedermayer]

On Sat, May 25, 2019 at 06:45:01PM +0200, Hendrik Leppkes wrote:
> On Sat, May 25, 2019 at 5:58 PM Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> >
> > On Fri, May 24, 2019 at 06:05:42PM +0200, Paul B Mahol wrote:
> > > Signed-off-by: Paul B Mahol <onemda at gmail.com>
> > > ---
> > >  libswresample/swresample.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/libswresample/swresample.c b/libswresample/swresample.c
> > > index 6d28e6a798..1ac5ef9a30 100644
> > > --- a/libswresample/swresample.c
> > > +++ b/libswresample/swresample.c
> > > @@ -164,6 +164,14 @@ av_cold int swr_init(struct SwrContext *s){
> > >          return AVERROR(EINVAL);
> > >      }
> > >
> > > +    if(s-> in_sample_rate <= 0){
> > > +        av_log(s, AV_LOG_ERROR, "Requested input sample rate %d is invalid\n", s->in_sample_rate);
> > > +        return AVERROR(EINVAL);
> > > +    }
> > > +    if(s->out_sample_rate <= 0){
> > > +        av_log(s, AV_LOG_ERROR, "Requested output sample rate %d is invalid\n", s->out_sample_rate);
> > > +        return AVERROR(EINVAL);
> > > +    }
> >
> > probably ok
> >
> > Only hypothetical issue i could see is convering sample types or channel
> > layout with unspecified sample rate, that is both 0.
> > dont know if that works currently but it at least semantically would make
> > sense
> >
> 
> Unspecified channel layout can at least make some sense, since you
> still have the channel count to properly handle the audio data, but
> unspecified sample rate? How would that ever work?

you sure can convert 0.5 0.0 1.0 to 128 0 255 you do not need to know
the sample rate.
For a real life example, that would be a raw pcm file, to convert it
from 32bit float to 16bit signed int only that needs to be known
neither the number of channels nor the sample rate is needed

or said differently, for this example, you could set the sample rate
to anything it would not affect the output. So it is basically not
needed for the process

not saying this is worth supporting. Just that it could be supported
and the case at least to me makes sense ...

thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Opposition brings concord. Out of discord comes the fairest harmony.
-- Heraclitus
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