[Ffmpeg-devel] WMA decoder speedup

Benjamin Larsson banan
Mon Mar 26 12:04:29 CEST 2007


Michael Niedermayer skrev:
> Hi
>
> On Thu, Mar 22, 2007 at 10:56:21PM +0100, Ian Braithwaite wrote:
>   
>> Hi,
>>
>>
>> I've been looking at the WMA decoder, and came across:
>>
>> /* XXX: optimize all that by build the window and
>>    multipying/adding at the same time */
>>
>> /* XXX: suppress this */
>>    memset(...
>>
>> so I gave it a shot.
>>
>>
>> On my test clip, I measure a speedup of about 13%, which is way
>> more than I was expecting!
>>
>>  wma.c    |    2 -
>>  wma.h    |    1
>>  wmadec.c |  113 +++++++++++++++++++++++++++++++--------------------------------
>>  wmaenc.c |    4 +-
>>  4 files changed, 60 insertions(+), 60 deletions(-)
>>     
>
> if regression tests pass and a few random wma files decode correctly
> then this is ok
>
>
> [...]
>   

Make test passed. Md5 of 2 decoded files where identical, old vs new 
code. Decoding time went from 2.1s to 1.6s on one test file. Thus patch 
commited. Everything tested on amd64 Linux.

MvH
Benjamin Larsson






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