[FFmpeg-devel] [PATCH] cabac: initialize all of ff_h264_cabac_tables programmatically.

wm4 nfxjfg at googlemail.com
Sat Aug 30 20:10:26 CEST 2014

On Sat, 30 Aug 2014 19:58:11 +0200
Reimar Döffinger <Reimar.Doeffinger at gmx.de> wrote:

> On 30.08.2014, at 19:46, Reimar Döffinger <Reimar.Doeffinger at gmx.de> wrote:
> > On 30.08.2014, at 19:01, wm4 <nfxjfg at googlemail.com> wrote:
> >> 
> >> but still I wonder why you'd optimize
> >> for binary size, in exchange for higher RAM usage. What is your
> >> motivation for doing this?
> > 
> > The only higher RAM usage would be when you actually use H.264, and it would be from the two additional lines of code.
> > When you are not using H.264 the RAM usage (with some caveats on what the linker does) will be several 100 bytes lower.
> Small amendment: I missed that Linux seems to use copy-on-write for the data section.
> This means that the first 512 bytes of the table could in theory end up being shared. You'd have to be lucky enough that they just end up on a different page than the rest of the array. At the same time, the extra RAM usage when H.264 is not used would be once per system, not per process.
> I still wouldn't count it as using "more RAM", especially considering not all OSes handle this as nicely as Linux, but it makes it a bit more borderline.

OK... never mind then.

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