[FFmpeg-devel] [PATCH] ffv1: more than 8 bit per RGB channel

Michael Niedermayer michaelni at gmx.at
Thu Aug 23 19:58:11 CEST 2012

On Thu, Aug 23, 2012 at 04:10:49PM +0200, Georg Lippitsch wrote:
> Am 22.08.2012, 23:52 Uhr, schrieb Michael Niedermayer <michaelni at gmx.at>:
> >also what effect does this has on en/decoding speed of 8/8/8 rgb ?
> >(that is once it works again)
> As you suggested, I did some measurements adding a timer around the
> loop in encode/decode_rgb_frame.
> It turned out that the if() did not really hurt, but the
> encode_line(s, w, sample[p], (p+1)/2, bits+1) caused a huge speed
> penalty (nearly 5%).
> So, I suggest going different branches depending on bit depth, as I
> do in the latest version of my patch
> The speed result is a bit weird though, because it even uses
> slightly less cycles than in the original code:
> Original: 4758587630 decicycles in rgb_frame, 64 runs, 0 skips
> My patch: 4757414280 decicycles in rgb_frame, 64 runs, 0 skips

patch applied



Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
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