ref: 733c5d6645b133b60d304c38fcb1398f94d0618c
dir: /sys/src/cmd/audio/scream/screamdec.c/
#include <u.h> #include <libc.h> char deffmt[] = "s16c2r44100"; char fmt[64]; uchar hdr[5]; uchar buf[2048]; int pfd[2]; char* getformat(uchar hdr[5]) { int freq, bits, chan; if(hdr[0] & 0x80) freq = 44100; else freq = 48000; freq *= hdr[0] & 0x7F; bits = hdr[1]; chan = hdr[2]; snprint(fmt, sizeof(fmt), "s%dc%dr%d", bits, chan, freq); return fmt; } void main(void) { int n; for(;;){ alarm(500); n = read(0, buf, sizeof(buf)); if(n < sizeof(hdr)) break; if(pfd[1] == 0 || memcmp(buf, hdr, sizeof(hdr)) != 0){ if(pfd[1] > 1){ close(pfd[1]); waitpid(); } if(strcmp(getformat(buf), deffmt) == 0){ pfd[1] = 1; } else { if(pipe(pfd) < 0) sysfatal("pipe: %r"); switch(fork()){ case -1: sysfatal("fork: %r"); case 0: close(pfd[1]); dup(pfd[0], 0); execl("/bin/audio/pcmconv", "pcmconv", "-i", fmt, nil); sysfatal("exec: %r"); } close(pfd[0]); } memmove(hdr, buf, sizeof(hdr)); } n -= sizeof(hdr); if(n <= 0) continue; if(write(pfd[1], buf+sizeof(hdr), n) != n) break; } exits(nil); }