try to read version

diff --git a/mp3read.c b/mp3read.c
index 52d08f1..0236f31 100644 (file)
--- a/mp3read.c
+++ b/mp3read.c
@@ -9,34 +9,52 @@
 #include <errno.h>
 
 #define MAX_READ 1024
-#define MAX_FILENAME 30
+#define MAX_FILENAME 32
+#define MAX_VER_ID 64
+
+/*
+info:
+http://www.dv.co.yu/mpgscript/mpeghdr.htm
+*/
 
 int main (int argc,char **argv)
 {
- int file_fd,n_exit,count;
- char buf;
+ int file_fd,exit,count;
+ unsigned char buf;
+ unsigned char header[3];
+ char mpeg_ver_id[MAX_VER_ID];
  char filename[MAX_FILENAME];
 
  strcpy(filename,argv[1]);
- printf("test: %s\n",filename);
 
  if((file_fd=open(filename,O_RDONLY))<=0) {
   puts("open failed");
   return -23;
  }
 
- if((lseek(file_fd,atoi(argv[2])-MAX_READ,SEEK_SET))<0) {
-  perror("lseek");
-  return -23;
- }
+ count=0;
+ exit=0;
+ while(!exit) {
+  printf("count=%d\n",count++);
+  read(file_fd,&buf,1);
+  if(buf==0xff) {
+   read(file_fd,&buf,1);
+   if(buf>=0xe0) {
+    puts("got frame header:");
+    exit=1;
+    header[0]=buf;
+    read(file_fd,header+1,2);
+
+    printf("debug: %x%x%x \n",header[0],header[1],header[2]);
+  
+    if(((header[0]&0x18)>>3)==0x00) strcpy(mpeg_ver_id,"MPEG Version 2.5");
+    else if(((header[0]&0x18)>>3)==0x10) strcpy(mpeg_ver_id,"MPEG Version 2 (ISO/IEC 13818-3)");
+    else if(((header[0]&0x18)>>3)==0x11) strcpy(mpeg_ver_id,"MPEG Version 1 (ISO/IEC 11172-3)");
+    else strcpy(mpeg_ver_id,"unknown");
 
- count=1;
- n_exit=1;
- while(n_exit) {
-  n_exit=read(file_fd,&buf,1);
-  count++;
-  putchar(buf);
-  if(count==MAX_READ) break;
+    printf("version: %s\n",mpeg_ver_id);
+   }
+  }
  }
 
  close(file_fd);