[Ffmpeg-devel] [PATCH] Apple Video Encoder (rpza)
Mon Jun 6 19:04:27 CEST 2005
Todd Kirby wrote:
> Ok, most of this stuff is easy but, what is the alternative to random?
> Is this a new requirement? I see lots of uses of random in the
I believe one of the overriding goals here is repeatability. It helps
for testing and validation. Using random numbers makes this difficult.
Even when using the same random seeds, I am not sure if the ANSI C spec
requires the actual random number generator to be implemented the same
way on different platforms.
I looked at the way random() is used in the video encoder:
+ r = (uint32_t)rgb24 + (uint32_t)(random() % 8);
+ g = (uint32_t)rgb24 + (uint32_t)(random() % 8);
+ b = (uint32_t)rgb24 + (uint32_t)(random() % 8);
+ int channel_value = color[channel] + ((random() % range) /
3.0) - (range / 6.0);
To get around using random(), maybe you could just write a program to
generate a static table of random values from 0..7. Copy the text of
those tables into the source and just iterate through the values,
wrapping when you hit the end. Encoding results should be repeatable.
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