[opus] [PATCH] Fix memory issue in Projection API
Jean-Marc Valin
jmvalin at jmvalin.ca
Fri Nov 24 17:15:11 UTC 2017
Hi Drew,
I noticed you reverted the
output[output_rows * i] = (tmp + 16384) >> 15;
from the previous patch. That's still good. What should have been
changed is the float version:
output[output_rows * i] = (1/32768.f) * ((tmp + 16384) >> 15);
which should just be:
output[output_rows * i] = (1/(32768.f*32768.f)) * tmp;
since there's no point in doing integer rounding when you have float
available.
Cheers,
Jean-Marc
On 11/23/2017 10:35 PM, Drew Allen wrote:
> Hi Jean-Marc,
>
> Attached is an updated patch. I had to include some of Mark's
> suggestions in order to get the tests to work correctly. I will still
> submit a separate patch for him for a few other concerns he had after
> this one clears.
>
> Cheers,
> Drew
>
> On Thu, Nov 23, 2017 at 10:42 AM Jean-Marc Valin <jmvalin at jmvalin.ca
> <mailto:jmvalin at jmvalin.ca>> wrote:
>
> Actually, there's also something wrong with the in_short() function. For
> floating point (#else case), you shouldn't need shifting since you're
> already doing the scaling through a float multiply.
>
> Jean-Marc
>
> On 11/23/2017 01:39 PM, Drew Allen wrote:
> > got it. actually that patch i sent you has something wrong with the
> > mapping_matrix_multiply_short_out... let me fix that and will send you
> > another patch soon.
> >
> > Cheers,
> > Drew
> >
> > On Thu, Nov 23, 2017 at 10:34 AM Jean-Marc Valin
> <jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> > <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>> wrote:
> >
> > On 11/23/2017 01:28 PM, Drew Allen wrote:
> > > To your first point, I was only trying to copy how
> _multistream_'s c
> > > files function in this way, possibly that's worth
> refactoring as well
> > > (as a separate patch).
> >
> > Well, the opus_multistream_decode_* calls were correct before your
> > patch. It's only the encode ones that have the issues (should be
> > addressed separately).
> >
> > Jean-Marc
> >
> > > On Thu, Nov 23, 2017 at 9:02 AM Jean-Marc Valin
> > <jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>
> > > <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>>> wrote:
> > >
> > > On 11/22/2017 06:23 PM, Drew Allen wrote:
> > > > 1) I didn't change how multistream_decode_float works
> in the
> > argument
> > > > list... I noticed it changes it's arguments depending
> on whether
> > > > FIXED_POINT is used. I copied this style for the
> projection
> > API as
> > > well.
> > > > If this isn't desired, we should make those changes
> separately.
> > > >
> > > > 2) See above.
> > >
> > > Just noticed the code will actually work because
> opus_val16 is
> > defined
> > > to the right thing, but I still think it's a bad idea. For
> > example, if
> > > you look at the public header, opus_projection_decode()
> has a pcm
> > > argument of type opus_int16*, so it's a bit confusing
> for the
> > C file to
> > > define pcm as opus_val16*, even if the two map to the same.
> > >
> > > > 3) I only zero out initially. For the matrix_multiply_out
> > > functions, we
> > > > need to be able to take a single decoded stream and
> add weighted
> > > > versions of it to each of the final output channels. This
> > zero-ing out
> > > > on stream 0 ensures the block is zero-set so we can
> > incrementally add
> > > > all the decoded streams to the output channels.
> > >
> > > OK, I see. In that case, you should replace the two for()
> > loops with
> > > just a single call to OPUS_COPY(). That should be both
> faster and
> > > simpler.
> > >
> > > > 4) See 3), short and float versions of multiply_out should
> > > function the
> > > > same.
> > >
> > > Again, I now see what that code is doing. Unfortunately,
> it means
> > > increased noise for fixed-point since we have to round
> > multiple times. I
> > > don't have a proposed fix for that, so I guess we'll have to
> > deal with
> > > it. However, instead of rounding tmp twice (>>8 followed by
> > +64>>7), you
> > > should only round once. That means (tmp+16384)>>15
> > >
> > > Cheers,
> > >
> > > Jean-Marc
> > >
> > > > Let me know your thoughts.
> > > >
> > > > Cheers,
> > > > Drew
> > > >
> > > > On Tue, Nov 21, 2017 at 7:39 PM Jean-Marc Valin
> > > <jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>
> > <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>>
> > > > <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>
> > <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>
> <mailto:jmvalin at jmvalin.ca <mailto:jmvalin at jmvalin.ca>>>>> wrote:
> > > >
> > > > Hi Drew,
> > > >
> > > > Had a look at your patch. I think it's on the
> right track --
> > > there's no
> > > > fundamental issue with it as far as I can tell.
> There's
> > a few
> > > > implementation issues though.
> > > >
> > > > 1) In opus_multi_stream_decode_float(), you
> changed the pcm
> > > argument
> > > > from float* to opus_val16*. That's a mistake and will
> > fail for
> > > > fixed-point. This should have shown up as an error
> on a
> > > fixed-point
> > > > build. Make sure you test that.
> > > >
> > > > 2) In opus_projection_decode(), you also changed
> the pcm
> > > argument to an
> > > > opus_val16*, which again will cause problems for
> the same
> > > reasons as 1).
> > > > Please check you haven't made that same mistake
> elsewhere.
> > > >
> > > > 3) In opus_projection_copy_channel_out_float() and
> > > > opus_projection_copy_channel_out_short(), you're
> zeroing the
> > > values with
> > > > this loop:
> > > > for (i=0;i<frame_size;i++)
> > > > {
> > > > for (j=0;j<dst_stride;j++)
> > > > {
> > > > float_dst[i*dst_stride+j] = 0;
> > > > }
> > > > }
> > > > That looks wrong, since you'll be overwriting all
> channels
> > > instead of
> > > > just the one you're copying. That should have come
> up in
> > > testing, no?
> > > >
> > > > 4) You might want to have a look at
> > > > mapping_matrix_multiply_channel_out_short(). I
> can't quite
> > > follow what
> > > > it's doing, but it seems wrong since the whole
> point of
> > adding
> > > the "tmp"
> > > > is to avoid rounding multiple times.
> > > >
> > > > I haven't had time to thoroughly review the changes to
> > > mapping_matrix.c,
> > > > but I'll do that on your revised version.
> > > >
> > > > Cheers,
> > > >
> > > > Jean-Marc
> > > >
> > > >
> > > >
> > > >
> > > > On 11/20/2017 05:15 PM, Drew Allen wrote:
> > > > > Hello,
> > > > >
> > > > > Attached is a patch to resolve a memory issue
> using the
> > > Projection API
> > > > > when compiling using a psuedo-stack / limited
> memory.
> > > > >
> > > > > Please let me any ?s you might have.
> > > > >
> > > > > Cheers,
> > > > > Drew
> > > > >
> > > > >
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> > > > >
> > > >
> > >
> >
>
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