[FFmpeg-devel] [PATCH] E-AC-3 spectral extension (bump)
Thu Mar 25 16:50:05 CET 2010
On Thu, Mar 25, 2010 at 03:52:31PM +0100, Christophe Gisquet wrote:
> 2010/3/24 Michael Niedermayer <michaelni at gmx.at>:
> > would we overall have fewer unaligned accesses if we would place the array
> > so that not element 0 but element 1 is aligned?
> I've just now see that this might be troublesome later on, as
> int32_to_float_fmul_scalar and ff_imdct_half are used on those buffers
> and both expect 16-bytes aligned data (movaps used).
> >> num_copy_sections can definitely be >1. ?That is the whole point of it.
> > if num_copy_sections is only rarely >1 than this optimization is maybe
> > not worth it
> At least the samples on mplayerhq and the French TNT-HD broadcasts are
> in this situation.
> Last but not least, I've used START/STOP_TIMER and oprofile to cycle
> counts and % of execution time. It appears that the CSI samples have
> CRC whose computation eats most of the runtime. Here are those figures
> as food for thought:
> | (1) | (2) | (3) | (4) | (5) | (6) |
> rambo | 1.0 | 64 | 3870 | 14000 | 11.2 | 0.0 | 11.2
> CSI | 5.1 | 256 | 5020 | 83000 | 0.9 | 81.4 | 5.1
> CSI | 2.0 | 128 | 1920 | 12700 | 0.3 | 81.1 | 1.6
i dont belive that crc calculation takes 80% of the time,
if it really does this is a bug
please make sure this percetage does not inlcude once run table init
on a very short file.
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Observe your enemies, for they first find out your faults. -- Antisthenes
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