beat

commit

0fdb0471e2e8afaa30f3c51f207a28c8eff31baf

parent

400aebaa8e6b0942aad55146b1f79008aa368be2

Author

Tobias Bengfort <tobias.bengfort@posteo.de>

Date

2019-12-17 14:35

avoid clipping

Diffstat

2 files changed, 11 insertions, 8 deletions

diff --git a/Makefile b/Makefile

@@ -3,7 +3,7 @@ SAMPLERATE = 44100
    3     3 FPB = $(shell echo $(SAMPLERATE) \* 60 / $(BPM) | bc)
    4     4 
    5     5 build/beat.flac: Makefile beat src/bumm.flac src/tack.flac
    6    -1 	./beat $@ $(SAMPLERATE) $$(($(FPB) / 2)) 8 0 src/bumm.flac 2 src/tack.flac 3 src/bumm.flac 4 src/bumm.flac 6 src/tack.flac
   -1     6 	./beat $@ $(SAMPLERATE) $$(($(FPB) / 2)) 8 2 0 src/bumm.flac 2 src/tack.flac 3 src/bumm.flac 4 src/bumm.flac 6 src/tack.flac
    7     7 
    8    -1 beat: beat.c
    9    -1 	gcc -lsndfile $< -o $@
   -1     8 beat: beat.c Makefile
   -1     9 	gcc -lm -lsndfile $< -o $@

diff --git a/beat.c b/beat.c

@@ -1,6 +1,7 @@
    1     1 #include <stdlib.h>
    2     2 #include <string.h>
    3     3 #include <sndfile.h>
   -1     4 #include <math.h>
    4     5 
    5     6 #define MIN(A, B) ((A) < (B) ? (A) : (B))
    6     7 
@@ -10,6 +11,7 @@ struct context {
   10    11     int frames;
   11    12     int buf_cur;
   12    13     size_t buf_len;
   -1    14     float factor;
   13    15     float *buf;
   14    16     float *buf2;
   15    17 };
@@ -39,9 +41,9 @@ void add_file_at_beat(const char *path, int beat, struct context ctx) {
   39    41                 sf_close(sndfile);
   40    42                 return;
   41    43             } else if (rel_pos >= ctx.buf_len) {
   42    -1                 ctx.buf2[rel_pos - ctx.buf_len] += fbuf[i];
   -1    44                 ctx.buf2[rel_pos - ctx.buf_len] += fbuf[i] * ctx.factor;
   43    45             } else {
   44    -1                 ctx.buf[rel_pos] += fbuf[i];
   -1    46                 ctx.buf[rel_pos] += fbuf[i] * ctx.factor;
   45    47             }
   46    48         }
   47    49     }
@@ -50,8 +52,8 @@ void add_file_at_beat(const char *path, int beat, struct context ctx) {
   50    52 }
   51    53 
   52    54 int main(int argc, char **argv) {
   53    -1     if (argc < 6 || argc % 2 != 1) {
   54    -1         printf("Usage: beat OUTFILE SAMPLERATE FRAMES_PER_BEAT BEATS BEAT INFILE [BEAT INFILE…]\n");
   -1    55     if (argc < 6 || argc % 2 != 0) {
   -1    56         printf("Usage: beat OUTFILE SAMPLERATE FRAMES_PER_BEAT BEATS TRACKS BEAT INFILE [BEAT INFILE…]\n");
   55    57         exit(1);
   56    58     }
   57    59 
@@ -60,6 +62,7 @@ int main(int argc, char **argv) {
   60    62     ctx.samplerate = atoi(argv[2]);
   61    63     ctx.frames_per_beat = atoi(argv[3]);
   62    64     ctx.frames = atoi(argv[4]) * ctx.frames_per_beat;
   -1    65     ctx.factor = 1 / sqrt(atoi(argv[5]));
   63    66 
   64    67     ctx.buf_len = MIN(ctx.frames / 4, 1 << 18);
   65    68     ctx.buf_cur = 0;
@@ -82,7 +85,7 @@ int main(int argc, char **argv) {
   82    85 
   83    86     SNDFILE *sndfile = sf_open(argv[1], SFM_WRITE, &sfinfo);
   84    87 
   85    -1     for (int i = 5; i + 1 < argc; i += 2) {
   -1    88     for (int i = 6; i + 1 < argc; i += 2) {
   86    89         int beat = atoi(argv[i]);
   87    90         char *path = argv[i + 1];
   88    91