[FFmpeg-cvslog] ac3enc: use MUL64() to multiply fixed-point coefficients

[Justin Ruggles]

On 03/09/2011 12:30 PM, Michael Niedermayer wrote:

> On Tue, Mar 08, 2011 at 06:18:44PM -0500, Justin Ruggles wrote:
>> On 03/08/2011 02:01 PM, Justin Ruggles wrote:
>>
>>> ffmpeg | branch: master | Justin Ruggles <justin.ruggles at gmail.com> | Tue Mar  8 13:18:55 2011 -0500| [67fc32ac6197a7fe265795d0bf60bf704464394e] | committer: Michael Niedermayer
>>>
>>> ac3enc: use MUL64() to multiply fixed-point coefficients
>>>
>>> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
>>>
>>>> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=67fc32ac6197a7fe265795d0bf60bf704464394e
>>> ---
>>>
>>>  libavcodec/ac3enc.c       |    8 ++++----
>>>  libavcodec/ac3enc_fixed.h |    2 ++
>>>  libavcodec/ac3enc_float.h |    2 ++
>>>  3 files changed, 8 insertions(+), 4 deletions(-)
>>>
>>
>>
>> This change is unnecessary and can be safely reverted.
> 
> i thought it improves speed on some cpus where MUL64 is optimized ?
> but i can revert if you want me to


Well, I wasn't thinking of that case.  The original purpose of the patch
was only because it was necessary in earlier versions of my patch set
where I was moving the rematrixing strategy decision to after the
coefficient scaling.

It might very well be faster though.  MAC64() would be another option.
I'll work on that and send a separate patch.

Thanks,
Justin