[FFmpeg-devel] [PATCH 2/5] fate: avoid framemd5, use framecrc its faster

Paul B Mahol onemda at gmail.com
Thu May 16 23:36:02 CEST 2013

On 5/16/13, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Thu, May 16, 2013 at 08:35:32PM +0200, Nicolas George wrote:
>> Le decadi 20 floreal, an CCXXI, Michael Niedermayer a ecrit :
>> > hmm, i get:
>> > ffmpeg -f rawvideo md5:  user    0m2.212s    sys 0m0.428s
>> > ffmpeg -f md5 -          user    0m2.192s    sys 0m0.408s
>> > ffmpeg -f crc -          user    0m0.356s    sys 0m0.408s
>> > ffmpeg -f null -         user    0m0.008s    sys 0m0.084s
>> > aviocat md5:             user    0m2.004s    sys 0m0.108s
>> > gnu md5sum               user    0m1.272s    sys 0m0.116s
>> > ffadler                  user    0m0.164s    sys 0m0.060s
>> >
>> > Note, my ffmpeg tests did read the random file as if it was
>> > rawvideo (which it was not) no real demuxing thus done
>> > test done with a random 900mb file on sandybridge i7 4ghz
>> It is hard to reproduce your runs, and the framework overhead may make
>> comparison less relevant.
>> I have written a small benchmark for various hash functions, I can send
>> the
>> program itself if wanted, and the results are below (the time is in
>> cycles
>> per byte).
>> You will notice that OpenSSL is always faster than lavu; the difference
>> is
>> negligible for SHA-2 on x86_32, but elsewhere it is significant, and it
>> is
>> even huge for MD5 on Atom, for some reason.
> under which license is the openssl code ? if its lgpl we should
> consider replacing ours by the openssl code. If not borrowing its
> tricks would make sense

its bsd license

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