[Ffmpeg-devel] dsputil arm patch

Måns Rullgård mans
Tue Apr 24 17:34:05 CEST 2007

Tao Huang wrote:
> M?ns Rullg?rd ??:
>>> When I benchmark this video with mplayer, it use 30s. I don't know why
>>> ffmpeg use so long time. But, the delta is more important.
>> Well, did you specify the correct CPU?  If you don't, the ARMv6
>> optimized IDCT isn't used.
> My patch is for some put*, NOT IDCT. Which version IDCT isn't important.

With the optimised IDCT some of those add/put functions are never called,
so it is relevant.

> Now I reconfigure ffmpeg with extra-cflags -mcpu=arm1136jf-s -mfpu=vfp
> -mfloat-abi=softfp

Hmm, the chip has a real floating point unit so you don't want softfloat

> configure output have:
> ARCH                      armv4l (generic)
> big-endian                no
> ARMv5TE enabled           yes
> ARMv6 enabled             yes
> IWMMXT enabled            no
> The ffmpeg output like this:
> FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2007 Fabrice Bellard, et al.
>   configuration: --prefix=/usr --extra-cflags=-mcpu=arm1136jf-s
> -mfpu=vfp -mfloat-abi=softfp
>   libavutil version: 49.4.0
>   libavcodec version: 51.40.4
>   libavformat version: 51.12.1
>   built on Apr 24 2007 22:03:50, gcc: 3.4.4 (release) (CodeSourcery ARM 2005q3-2)

I used gcc 4.1.1.  Maybe that's what's making the difference.

M?ns Rullg?rd
mans at mansr.com

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