[FFmpeg-devel] [PATCH] avcodec/alsdec: implement floating point decoding

[Michael Niedermayer]

On Sun, Jul 17, 2016 at 09:00:48AM +0530, Umair Khan wrote:
> Hi,
> 
> On Sun, Jul 17, 2016 at 12:25 AM, Thilo Borgmann <thilo.borgmann at mail.de> wrote:
> > Hi,
> >
> >> From 70e65b26cc3f84c9c664c30808b43a5e1cf16eaa Mon Sep 17 00:00:00 2001
> >> From: Umair Khan <omerjerk at gmail.com>
> >> Date: Sat, 16 Jul 2016 23:52:39 +0530
> >> Subject: [PATCH 1/1] avcodec/alsdec: implement floating point decoding
> >>
> >> It conforms to RM22 version of the reference codec.
> >>
> >> Signed-off-by: Umair Khan <omerjerk at gmail.com>
> >> ---
> >>  libavcodec/Makefile           |   2 +-
> >>  libavcodec/alsdec.c           | 284 +++++++++++++++++++++++++++++++++++++++++-
> >>  libavcodec/mlz.c              | 171 +++++++++++++++++++++++++
> >>  libavcodec/mlz.h              |  69 ++++++++++
> >>  libavutil/softfloat_ieee754.h | 115 +++++++++++++++++
> >>  5 files changed, 638 insertions(+), 3 deletions(-)
> >>  create mode 100644 libavcodec/mlz.c
> >>  create mode 100644 libavcodec/mlz.h
> >>  create mode 100644 libavutil/softfloat_ieee754.h
> >>
> >> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> >> index abef19e..a03adf5 100644
> >> --- a/libavcodec/Makefile
> >> +++ b/libavcodec/Makefile
> >> @@ -163,7 +163,7 @@ OBJS-$(CONFIG_ALAC_DECODER)            += alac.o alac_data.o alacdsp.o
> >>  OBJS-$(CONFIG_ALAC_ENCODER)            += alacenc.o alac_data.o
> >>  OBJS-$(CONFIG_ALIAS_PIX_DECODER)       += aliaspixdec.o
> >>  OBJS-$(CONFIG_ALIAS_PIX_ENCODER)       += aliaspixenc.o
> >> -OBJS-$(CONFIG_ALS_DECODER)             += alsdec.o bgmc.o mpeg4audio.o
> >> +OBJS-$(CONFIG_ALS_DECODER)             += alsdec.o bgmc.o mlz.o mpeg4audio.o
> >>  OBJS-$(CONFIG_AMRNB_DECODER)           += amrnbdec.o celp_filters.o   \
> >>                                            celp_math.o acelp_filters.o \
> >>                                            acelp_vectors.o             \
> >> diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
> >> index a7e58a2..c710fc3 100644
> >> --- a/libavcodec/alsdec.c
> >> +++ b/libavcodec/alsdec.c
> >> @@ -35,8 +35,11 @@
> >>  [...]
> >>
> >> +/** multiply two softfloats and handle the rounding off
> >> + */
> >> +static SoftFloat_IEEE754 multiply(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {
> >> [...]
> >
> > Why is this in alsdec.c?
> 
> This is not the actual IEEE 754 multiplication. It is as is mentioned
> in the reference spec.
> The typical one for 754 floats, I've implemented here separately -
> https://github.com/omerjerk/FFmpeg/commit/d6cd4bf66b9da46dd87580d7d974ce44abdcfba2#diff-4dd4b2d8d523f336fbefa96e9252187cR93
> 
> > [...]
> >
> >> diff --git a/libavcodec/mlz.c b/libavcodec/mlz.c
> >> new file mode 100644
> >> index 0000000..cb2ed6a
> >> --- /dev/null
> >> +++ b/libavcodec/mlz.c
> >> [...]
> >
> >> +static int input_code(GetBitContext* gb, int len) {
> >> +    int tmp_code = 0;
> >> +    int i;
> >> +    for (i = 0; i < len; ++i) {
> >> +        tmp_code += get_bits1(gb) << i;
> >> +    }
> >> +    return tmp_code;
> >> +}
> >
> > Is there nothing in get_bits.h that solves that already?
> >
> > -Thilo
> 
> I'm not sure. It is just reading the bits in the reverse order. May be
> someone else can help.

theres asv2_get_bits()
if it works here it could be shared

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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