nausea

curses audio visualizer
git clone git://git.2f30.org/nausea.git
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commit 0ee432c19f9f67d3d8eb5b0d0352168cfb957b9c
parent 5773c9bdcd061d2f9d417d63d1f0c2f8bcf8f89d
Author: sin <sin@2f30.org>
Date:   Wed Nov 20 10:40:17 +0000

Halve the size of the DFT in/out buffers

Do not use memset() as it might not match the representation
of 0 correctly for double types.

We mix left/right channels into a single buffer which we then
hand off to fftw.

Diffstat:
spectrum.c | 25++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/spectrum.c b/spectrum.c @@ -58,21 +58,24 @@ static struct color_range { static void init(struct frame *fr) { + unsigned i; + fr->fd = open(fname, O_RDONLY | O_NONBLOCK); if (fr->fd == -1) err(1, "open"); fr->buf = malloc(nsamples * sizeof(int16_t)); fr->res = malloc(nsamples / 2 * sizeof(unsigned)); - fr->in = fftw_malloc(nsamples * sizeof(double)); - fr->out = fftw_malloc(nsamples * sizeof(fftw_complex)); + fr->in = fftw_malloc(nsamples / 2 * sizeof(double)); + fr->out = fftw_malloc(nsamples / 2 * sizeof(fftw_complex)); - memset(fr->buf, 0, nsamples * sizeof(int16_t)); - memset(fr->res, 0, nsamples / 2 * sizeof(unsigned)); - memset(fr->in, 0, nsamples * sizeof(double)); - memset(fr->out, 0, nsamples * sizeof(fftw_complex)); + for (i = 0; i < nsamples / 2; i++) { + fr->in[i] = 0.; + fr->out[i][0] = 0.; + fr->out[i][1] = 0.; + } - fr->plan = fftw_plan_dft_r2c_1d(nsamples, fr->in, fr->out, + fr->plan = fftw_plan_dft_r2c_1d(nsamples / 2, fr->in, fr->out, FFTW_ESTIMATE); } @@ -93,7 +96,7 @@ static void update(struct frame *fr) { ssize_t n, gotsamples; - unsigned i, j; + unsigned i; n = read(fr->fd, fr->buf, nsamples * sizeof(int16_t)); if (n == -1) @@ -101,9 +104,9 @@ update(struct frame *fr) gotsamples = n / sizeof(int16_t); - for (i = 0, j = 0; i < nsamples; i++, j++) { - fr->in[i] = 0; - if (j < gotsamples) { + for (i = 0; i < nsamples / 2; i++) { + fr->in[i] = 0.; + if (i < gotsamples) { /* average the two channels */ fr->in[i] = fr->buf[i * 2 + 0]; fr->in[i] += fr->buf[i * 2 + 1];