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Problems encoding with Intel processors

I need that someone can replicate what it happens to me.

I've used 3 different Intel processors (i7 4790K, i7 8700 and i5 9600k) with the same results.

If you encode with opus, ogg, qaac, lossywav and fdk-aac the same wav file twice, with the same parameters, you get two different files, Its impossible to get two identical files.

But if you use flac, tak, wavpack, mpc and mp3 and repeat the same test, you get two identical files, same CRC.

I made a test with opus encoding the same wav file 5 times and you get 5 different files, so i wonder which is the good one.

Is this normal? I think that it's not

Someone with AMD processors could repeat the same test to see that it's only a Intel problem or not.

Re: Problems encoding with Intel processors

Reply #1
Is this normal? I think that it's not
It is normal and doesn't depend on your CPU. If you compared audio data you would notice it's identical in all file pairs.
Ogg formats for example use serial number to differentiate between chains, this is by default randomly generated. If you force it to a constant number you get bit-identical output. The differences in MP4 container are only in few bytes, it's probably something similar randomly generated but I'm not familiar enough with the format. I assumed lossywav would create different output with random dither but it had only two differing bytes somewhere in the beginning. I didn't examine closer what it was but the test files produced bit-identical audio output.

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