Playing audio using libmpg123 and libao

err.txt

$ ./main ~/Music/mpd/demo.mp3
ID3V2 tag found
Dil Main Chuppa Ke Pyar Ka
Angelique Kidjo
Oyo
World
SIGTRAP: trace trap
pc: 0x7fff844715c0


goroutine 2 [3]:
return /Users/deepak/code/public/go/src/pkg/runtime/amd64/asm.s:384
        return()
runtime.cgocall+0x108 /Users/deepak/code/public/go/src/pkg/runtime/cgocall.c:136
        runtime.cgocall(0x15825, 0x21b8e60, 0x0, 0x15010)
mp3._Cfunc_ao_initialize+0x2f /Users/deepak/code/personal/gomp3/_obj/_cgo_defun.c:163
        mp3._Cfunc_ao_initialize(0xf840022510, 0x100000001)
mp3.DecodeTrack+0x589 /Users/deepak/code/personal/gomp3/_obj/music.cgo1.go:-133
        mp3.DecodeTrack(0x7fff5fbff7d7, 0x49)
main._func_001+0x3e /Users/deepak/code/personal/gomp3/main.go:9
        main._func_001()
runtime.goexit /Users/deepak/code/public/go/src/pkg/runtime/proc.c:178
        runtime.goexit()
----- goroutine created by -----
main.main+0x2b /Users/deepak/code/personal/gomp3/main.go:10

goroutine 1 [3]:
runtime.entersyscall+0x78 /Users/deepak/code/public/go/src/pkg/runtime/proc.c:639
        runtime.entersyscall()
syscall.Syscall6+0x5 /Users/deepak/code/public/go/src/pkg/syscall/asm_darwin_amd64.s:38
        syscall.Syscall6()
syscall.Select+0x63 /Users/deepak/code/public/go/src/pkg/syscall/zsyscall_darwin_amd64.g
o:754
        syscall.Select(0x100000000, 0x0, 0x0, 0x0, 0xf8400223f0, ...)
syscall.Sleep+0x7a /Users/deepak/code/public/go/src/pkg/syscall/syscall_bsd.go:150
        syscall.Sleep(0x12a05f200, 0x8, 0xf8400223b0, 0x18e8c)
time.sysSleep+0x25 /Users/deepak/code/public/go/src/pkg/time/sys_posix.go:13
        time.sysSleep(0x12a05f200, 0x0, 0x4e0aa618, 0x122ba4451b0996c8)
time.sleep+0x40 /Users/deepak/code/public/go/src/pkg/time/sys.go:44
        time.sleep(0x122ba443f103a4c8, 0x12a05f200, 0x21b7f90, 0x202b, 0x8, ...)
time.Sleep+0x33 /Users/deepak/code/public/go/src/pkg/time/sys.go:33
        time.Sleep(0x12a05f200, 0x0, 0xde02, 0x2e64)
main.main+0x40 /Users/deepak/code/personal/gomp3/main.go:12
        main.main()
runtime.mainstart+0xf /Users/deepak/code/public/go/src/pkg/runtime/amd64/asm.s:77
        runtime.mainstart()
runtime.goexit /Users/deepak/code/public/go/src/pkg/runtime/proc.c:178
        runtime.goexit()
----- goroutine created by -----
_rt0_amd64+0x8e /Users/deepak/code/public/go/src/pkg/runtime/amd64/asm.s:64
rax     0x0
rbx     0x7fff8446fb58
rcx     0x7fff5fbff7b8
rdx     0x7fff5fbff6d8
rdi     0x0
rsi     0x7fff5fbff6c0
rbp     0xb00809b0
rsp     0xb0080160
r8      0x7fff5fc40548
r9      0x2201060
r10     0x1
r11     0x3
r12     0x7fff84470eb0
r13     0x7fff5fc404a0
r14     0x5
r15     0x2200bf0
rip     0x7fff844715c0
rflags  0x246
cs      0x27
fs      0x0
gs      0x0

main.go

package main

import "mp3"
import "os"
import "time"

func main() {
	go func() {
		mp3.DecodeTrack(os.Args[1])
	}()

	time.Sleep(5e9)
}

music.go

package mp3

// #cgo LDFLAGS: -lmpg123 -lao -ldl -lm
/*
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include "mpg123.h"
#include <ao/ao.h>
*/
import "C"

import (
        "fmt"
	"unsafe"
)

func DecodeTrack(file string) {

        var v1 *C.mpg123_id3v1
        var v2 *C.mpg123_id3v2

        C.mpg123_init()
        defer C.mpg123_exit()

        m := C.mpg123_new(nil, nil)
        defer C.mpg123_delete(m)

        f := C.CString(file)

        if err := C.mpg123_open(m, f); err != C.MPG123_OK {
                panic("Error reading file")
        }
        defer C.mpg123_close(m)

        C.mpg123_scan(m)
        meta := C.mpg123_meta_check(m)

        if meta == C.MPG123_ID3 && C.mpg123_id3(m, &v1, &v2) == C.MPG123_OK {
                var title, artist, album, genre string
                switch false {
                case v2 == nil:
                        fmt.Println("ID3V2 tag found")
                        title = C.GoString(v2.title.p)
                        artist = C.GoString(v2.artist.p)
                        album = C.GoString(v2.album.p)
                        genre = C.GoString(v2.genre.p)

                case v1 == nil:
                        fmt.Println("ID3V2 tag found")
                        title = C.GoString(&v1.title[0])
                        artist = C.GoString(&v1.artist[0])
                        album = C.GoString(&v1.album[0])
                        genre = "Unknown" // FIXME convert int to string
                }

                fmt.Println(title)
                fmt.Println(artist)
                fmt.Println(album)
                fmt.Println(genre)
        }


	C.ao_initialize()
	defer C.ao_shutdown()

	default_driver := C.ao_default_driver_id()
	var format C.ao_sample_format
	var device *C.ao_device

	//C.memset(&format,0,unsafe.Sizeof(format))
	var channels, encoding C.int
	var rate C.long
	C.mpg123_getformat(m, &rate, &channels, &encoding)
	format.bits = 16
	format.channels = channels
	format.rate = C.int(rate)
	format.byte_format = C.AO_FMT_LITTLE

	device = C.ao_open_live(default_driver, &format, nil)
	if device == nil {
		fmt.Println("Error opening device")
		return
	}
	defer C.ao_close(device)

	var ret C.int
	var fill C.size_t
	buf := make([]C.uchar,1024*16)

        for {
                ret = C.mpg123_read(m, (*C.uchar)(unsafe.Pointer(&buf)), 16*1024, &fill)
		if ret == C.MPG123_DONE {
			break
		}
		C.ao_play(device,(*C.char)(unsafe.Pointer(&buf)),16*1024)
        }
}