diff --git a/libmpdemux/mp3_hdr.c b/libmpdemux/mp3_hdr.c
index a4834f4f81..ac2d0876e1 100644
--- a/libmpdemux/mp3_hdr.c
+++ b/libmpdemux/mp3_hdr.c
@@ -17,6 +17,7 @@
  */
 
 #include <stdio.h>
+#include <stdint.h>
 
 #include "config.h"
 #include "mp3_hdr.h"
@@ -24,7 +25,7 @@
 
 //----------------------- mp3 audio frame header parser -----------------------
 
-static int tabsel_123[2][3][16] = {
+static const uint16_t tabsel_123[2][3][16] = {
    { {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0},
      {0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,0},
      {0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,0} },
@@ -34,29 +35,28 @@ static int tabsel_123[2][3][16] = {
      {0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,0} }
 };
 
-static long freqs[9] = { 44100, 48000, 32000,	// MPEG 1.0
-			 22050, 24000, 16000,   // MPEG 2.0
-			 11025, 12000,  8000};  // MPEG 2.5
+static const int freqs[9] = { 44100, 48000, 32000,   // MPEG 1.0
+                              22050, 24000, 16000,   // MPEG 2.0
+                              11025, 12000,  8000};  // MPEG 2.5
 
 /*
  * return frame size or -1 (bad frame)
  */
 int mp_get_mp3_header(unsigned char* hbuf,int* chans, int* srate, int* spf, int* mpa_layer, int* br){
-    int stereo,ssize,lsf,framesize,padding,bitrate_index,sampling_frequency, divisor;
+    int stereo,lsf,framesize,padding,bitrate_index,sampling_frequency, divisor;
     int bitrate;
-    int layer, mult[3] = { 12000, 144000, 144000 };
-    unsigned long newhead =
+    int layer;
+    static const int mult[3] = { 12000, 144000, 144000 };
+    uint32_t newhead =
       hbuf[0] << 24 |
       hbuf[1] << 16 |
       hbuf[2] <<  8 |
       hbuf[3];
 
-//    printf("head=0x%08X\n",newhead);
-
     // head_check:
     if( (newhead & 0xffe00000) != 0xffe00000 ){
-	mp_msg(MSGT_DEMUXER,MSGL_DBG2,"head_check failed\n");
-	return -1;
+      mp_msg(MSGT_DEMUXER,MSGL_DBG2,"head_check failed\n");
+      return -1;
     }
 
     layer = 4-((newhead>>17)&3);
@@ -65,76 +65,54 @@ int mp_get_mp3_header(unsigned char* hbuf,int* chans, int* srate, int* spf, int*
       return -1;
     }
 
-    sampling_frequency = ((newhead>>10)&0x3);  // valid: 0..2
+    sampling_frequency = (newhead>>10)&0x3;  // valid: 0..2
     if(sampling_frequency==3){
-	mp_msg(MSGT_DEMUXER,MSGL_DBG2,"invalid sampling_frequency\n");
-	return -1;
+      mp_msg(MSGT_DEMUXER,MSGL_DBG2,"invalid sampling_frequency\n");
+      return -1;
     }
 
-    if( newhead & ((long)1<<20) ) {
+    if( newhead & (1<<20) ) {
       // MPEG 1.0 (lsf==0) or MPEG 2.0 (lsf==1)
-      lsf = (newhead & ((long)1<<19)) ? 0x0 : 0x1;
-      sampling_frequency += (lsf*3);
+      lsf = !(newhead & (1<<19));
+      sampling_frequency += lsf*3;
     } else {
       // MPEG 2.5
       lsf = 1;
       sampling_frequency += 6;
     }
 
-//    crc = ((newhead>>16)&0x1)^0x1;
-    bitrate_index = ((newhead>>12)&0xf);  // valid: 1..14
-    padding   = ((newhead>>9)&0x1);
-//    fr->extension = ((newhead>>8)&0x1);
-//    fr->mode      = ((newhead>>6)&0x3);
-//    fr->mode_ext  = ((newhead>>4)&0x3);
-//    fr->copyright = ((newhead>>3)&0x1);
-//    fr->original  = ((newhead>>2)&0x1);
-//    fr->emphasis  = newhead & 0x3;
+    bitrate_index = (newhead>>12)&0xf;  // valid: 1..14
+    padding   = (newhead>>9)&0x1;
 
-    stereo    = ( (((newhead>>6)&0x3)) == 3) ? 1 : 2;
-
-// !checked later through tabsel_123[]!
-//    if(!bitrate_index || bitrate_index==15){
-//      mp_msg(MSGT_DEMUXER,MSGL_DBG2,"Free format not supported.\n");
-//      return -1;
-//    }
-
-    if(lsf)
-      ssize = (stereo == 1) ? 9 : 17;
-    else
-      ssize = (stereo == 1) ? 17 : 32;
-    if(!((newhead>>16)&0x1)) ssize += 2; // CRC
+    stereo    = ( ((newhead>>6)&0x3) == 3) ? 1 : 2;
 
     bitrate = tabsel_123[lsf][layer-1][bitrate_index];
     framesize = bitrate * mult[layer-1];
 
     mp_msg(MSGT_DEMUXER,MSGL_DBG2,"FRAMESIZE: %d, layer: %d, bitrate: %d, mult: %d\n",
-    	framesize, layer, tabsel_123[lsf][layer-1][bitrate_index], mult[layer-1]);
+           framesize, layer, tabsel_123[lsf][layer-1][bitrate_index], mult[layer-1]);
     if(!framesize){
-	mp_msg(MSGT_DEMUXER,MSGL_DBG2,"invalid framesize/bitrate_index\n");
-	return -1;
+      mp_msg(MSGT_DEMUXER,MSGL_DBG2,"invalid framesize/bitrate_index\n");
+      return -1;
     }
 
-    divisor = (layer == 3 ? (freqs[sampling_frequency] << lsf) : freqs[sampling_frequency]);
+    divisor = layer == 3 ? (freqs[sampling_frequency] << lsf) : freqs[sampling_frequency];
     framesize /= divisor;
+    framesize += padding;
     if(layer==1)
-      framesize = (framesize+padding)*4;
-    else
-      framesize += padding;
+      framesize *= 4;
 
-//    if(framesize<=0 || framesize>MAXFRAMESIZE) return FALSE;
-    if(srate) {
+    if(srate)
       *srate = freqs[sampling_frequency];
-      if(spf) {
-        if(layer == 1)
-	  *spf = 384;
-        else if(layer == 2)
-	  *spf = 1152;
-        else if(*srate < 32000)
-          *spf = 576;
-        else
-	  *spf = 1152;
-      }
+    if(spf) {
+      if(layer == 1)
+        *spf = 384;
+      else if(layer == 2)
+        *spf = 1152;
+      else if(sampling_frequency > 2) // not 1.0
+        *spf = 576;
+      else
+        *spf = 1152;
     }
     if(mpa_layer) *mpa_layer = layer;
     if(chans) *chans = stereo;