On Sun, Jul 17, 2016 at 3:38 PM, Michael Niedermayer
<mich...@niedermayer.cc> wrote:
> On Sun, Jul 17, 2016 at 11:54:49AM +0200, Michael Niedermayer wrote:
>> 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.borgm...@mail.de>
>> > wrote:
>> > > Hi,
>> > >
>> > >> From 70e65b26cc3f84c9c664c30808b43a5e1cf16eaa Mon Sep 17 00:00:00 2001
>> > >> From: Umair Khan <omerj...@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 <omerj...@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
>
> note though asv2_get_bits() is maximum 8 bits, for more bits more
> table lookups or a bigger table is needed
What should be the best way to use this function? It is not present in
any header file.
- Umair
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