[FFmpeg-devel] [PATCH] AAC: optimise bitstream reading in decode_spectrum_and_dequant()

Robert Swain robert.swain
Fri Jan 15 14:37:16 CET 2010


On 15/01/10 13:41, M?ns Rullg?rd wrote:
> Robert Swain<robert.swain at gmail.com>  writes:
>
>> On 15/01/10 05:10, Mans Rullgard wrote:
>>> Using the low-level macros directly avoids redundant open/update/close
>>> cycles.
>>>
>>> 2-3% faster on ARM, PPC, and Core i7.
>>
>> Nice! Keep them coming. :)
>>
>>> ---
>>>    libavcodec/aac.c |   93 +++++++++++++++++++++++++++++++++++++----------------
>>>    1 files changed, 65 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/libavcodec/aac.c b/libavcodec/aac.c
>>> index 393f2e6..0fbab77 100644
>>> --- a/libavcodec/aac.c
>>> +++ b/libavcodec/aac.c
>>
>> [...]
>>
>>> -                            const int index = get_vlc2(gb, vlc_tab, 8, 2);
>>> +                            int code;
>>
>> My only comment is that this variable rename seems unrelated. Apply
>> that change separately in my opinion.
>
> The GET_VLC macro declares a temp variable called index, so it has to
> be renamed.

Then maybe either add a comment to the macro to this effect, or 
obfuscate the name of the variable in the macro a bit so name clashes 
shouldn't occur.

Otherwise, OK to apply.

Regards,
Rob



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