[vlc-devel] [PATCH] avcodec: remove the VLC DSP mask

[Martin Storsjö]

On Mon, 24 Feb 2014, Jean-Baptiste Kempf wrote:

> Le 24/02/2014 10:04, Rafaël Carré a écrit :
>> Hello,
>> 
>> On 02/22/14 18:34, Rémi Denis-Courmont wrote:
>>> libavutil will always check for all CPU features that it understands,
>>> even those VLC masked. Thus masking features provides no savings.
>>> 
>>> libavutil runs more tests than VLC. Depending on the platform and
>>> operating system combination, libavutil is either as conservative or
>>> more conservative than VLC. As such masking features provides no extra
>>> safety.
>>> 
>>> So overall, GetVlcDspMask() is useless, at least nowadays.
>> 
>> OK
>
> Not really OK for me.
>
> As far as I remember, this detection in libav never worked for non-NEON 
> cortex A9 devices, aka tegra2.
> So, if this is still the case, this is a clear no from me.

AFAIK the cpu feature detection in libav should work just fine even for 
tegra2 - if not please file a bug.

See e.g. https://fate.libav.org/armv7a-linux-gcc-no-neon/20140224052850 
which runs with --enable-neon even though the device itself doesn't have 
neon.

// Martin