[Ffmpeg-devel] dv encoder speed
Mon Aug 29 12:49:03 CEST 2005
Mark Rages wrote:
> As I posted in another message, I need the dv encoder to run a little
> bit faster so I can do realtime processing on my AMD64 machine.
> Profiling gives this result:
> gprof ffmpeg | head
> Flat profile:
> Each sample counts as 0.01 seconds.
> % cumulative self self total
> time seconds seconds calls s/call s/call name
> 58.58 127.29 127.29 247050 0.00 0.00 dv_encode_video_segment
> 11.29 151.83 24.54 190769 0.00 0.00 dv_guess_qnos
> 7.99 169.19 17.37 10224352 0.00 0.00 dv_decode_ac
> 5.13 180.33 11.14 6204629 0.00 0.00 ff_fdct_sse2
> 4.48 190.06 9.73 6457910 0.00 0.00 ff_simple_idct_put_mmx
> So most of the time is getting spent in dv_encode_video_segment. No
> suprise. I need to determine how to get finer-grained profiling data.
Looks like quite a few functions are getting inlined into
dv_encode_video_segment(). You could try disabling the inlining, that
would make the results slightly more coarse-grained.
From looking at the comment above dv_encode_video_segment():
* This is a very rough initial implementaion. The performance is
* horrible and the weighting is missing. But it's missing from the
* decoding step also -- so at least we're on the same page with
it looks as if there might be some obvious candidates for optimization
there (but I haven't looked at the code).
Inst. f. Neuro- and Bioinformatics
Ratzeburger Allee 160, D-23538 Luebeck
Phone: +49 451 500 5514
Fax: +49 451 500 5502
boehme at inb.uni-luebeck.de
More information about the ffmpeg-devel