[FFmpeg-user] Audio resampler (SoX) returns different result
barsnick at gmx.net
Mon Nov 19 16:02:02 EET 2018
On Mon, Nov 19, 2018 at 16:14:03 +0800, 林至善 wrote:
> I need a down-sampled(=8kHz) version of my input.wav file (=16kHz).
> According to
> I use the command below
> ffmpeg -i In16k.wav -af aresample=resampler=soxr -ar 8000 Out8k.wav
> It works well, but I found that every time I run the command above,
> it returns the "Out8k.wav" with a slightly different(in PCM value).
Interesting. But first of all, I believe your command line is wrong.
"-ar" uses ffmpeg's native resampler, I believe. Using the filter, you
need to pass the rate to the filter itself:
ffmpeg -i In16k.wav -af aresample=resampler=soxr:sample_rate=8000 Out8k.wav
You could also just use any other resampler, e.g. by omitting "-af
I don't have soxr support, so I can't reproduce your issue. It should
be deterministic. Perhaps some metadata thing.
> *If I want a resampler which always returns the same result, how can I do?
Can you try whether the command line option "-bitexact" changes
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