[FFmpeg-devel] av_ctz optimization

James Almer jamrial at gmail.com
Sun Oct 11 18:06:04 CEST 2015

On 10/11/2015 8:01 AM, Ronald S. Bultje wrote:
> Hi,
> On Sat, Oct 10, 2015 at 10:50 PM, James Almer <jamrial at gmail.com> wrote:
>> On 10/10/2015 11:44 PM, Ganesh Ajjanagadde wrote:
>>> Hi all,
>>> Turns out that the De-Bruijn method can be used to speed up av_ctz as
>>> well. But before going about it, I was curious as to why such an
>>> interface is actually public. It makes absolutely zero sense to me:
>>> usage is limited exactly to one location, namely libavcodec/flacenc.c.
>>> Was this an accident?
>>> Regards,
>>> Ganesh
>> It's not really public since intmath.h is not an installed header.
>> Why it exists and is used instead of ff_ctz, i don't know.
> Looks like it was added for use in flacenc, and we typically don't share
> ff_ symbols between libraries. However, since it's inlined anyway, I'm not
> sure anyone cares. Maybe time to remove it?
> Ronald

We're still in ABI breaking season so it's fine if we do it asap.
flacenc can use ff_ctz just fine.

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