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

[Umair Khan]

Updated patch.

On Tue, Jul 19, 2016 at 8:19 PM, Thilo Borgmann <thilo.borgmann at mail.de> wrote:
> Am 19.07.16 um 15:42 schrieb Umair Khan:
>> On Tue, Jul 19, 2016 at 5:20 PM, Thilo Borgmann <thilo.borgmann at mail.de> wrote:
>>> Am 19.07.16 um 09:22 schrieb Umair Khan:
>>>> On Tue, Jul 19, 2016 at 12:29 PM, Paul B Mahol <onemda at gmail.com> wrote:
>>>>>
>>>>> On 7/19/16, Umair Khan <omerjerk at gmail.com> wrote:
>>>>>> On Tue, Jul 19, 2016 at 3:08 AM, Michael Niedermayer
>>>>>> <michael at niedermayer.cc> wrote:
>>>>>>> On Mon, Jul 18, 2016 at 11:42:48PM +0530, Umair Khan wrote:
>>>>>>>> On Sun, Jul 17, 2016 at 3:38 PM, Michael Niedermayer
>>>>>>>> <michael at 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.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;
>>>                              |=
>>> should be better.
>>>
>>>>>>>>>>>>> +    }
>>>>>>>>>>>>> +    return tmp_code;
>>>>>>>>>>>>> +}
>>>
>>> Also, you could revert it byte-wise using ff_revert[]... if len is often bigger
>>> than 8 that might be worth it.
>>
>> I didn't get you.
>
> tmp_code |= get_bits1(gb) << i;
>
>
>> I tried logging that variable and len is always greater than 8. So
>> what should we go with?
>> It was 9 or 10 for the file I ran. And going with the logic of lzw, it
>> will hardly be greater than 11 ever.
>
> I think it would not benefit enough from ff_reverse then. Keep the loop.
>
> -Thilo
>
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