From 2c07e78efc0e8ab7150eef7ae92af32b2389146a Mon Sep 17 00:00:00 2001
From: Linus Nielsen Feltzing <linus@haxx.se>
Date: Mon, 10 Mar 2003 18:25:40 +0000
Subject: Don't accidentally add Xing headers to CBR files

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@3419 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/id3.c     |  2 +-
 firmware/mp3data.c | 22 ++++++++++++++----
 firmware/mpeg.c    | 67 ++++++++++++++++++++++++++++++------------------------
 3 files changed, 56 insertions(+), 35 deletions(-)

diff --git a/firmware/id3.c b/firmware/id3.c
index ab638807c3..96b660658d 100644
--- a/firmware/id3.c
+++ b/firmware/id3.c
@@ -497,7 +497,7 @@ static int getsonglength(int fd, struct mp3entry *entry)
     entry->has_toc = info.has_toc;
     memcpy(entry->toc, info.toc, sizeof(info.toc));
 
-    entry->xing_header_pos = info.xing_header_pos;
+    entry->vbr_header_pos = info.vbr_header_pos;
     
     /* Update the seek point for the first playable frame */
     entry->first_frame_offset = bytecount;
diff --git a/firmware/mp3data.c b/firmware/mp3data.c
index 21f01ea19e..f38b51c8f4 100644
--- a/firmware/mp3data.c
+++ b/firmware/mp3data.c
@@ -555,9 +555,9 @@ int count_mp3_frames(int fd, int startpos, int filesize,
     int cnt;
     int progress_chunk = filesize / 50; /* Max is 50%, in 1% increments */
     int progress_cnt = 0;
+    bool is_vbr = false;
+    int last_bitrate = 0;
 
-    /* Nasty stuff to avoid passing the file handle around */
-    
     if(lseek(fd, startpos, SEEK_SET) < 0)
         return -1;
 
@@ -569,6 +569,14 @@ int count_mp3_frames(int fd, int startpos, int filesize,
     
     while((header = buf_find_next_frame(fd, &bytes, -1, header))) {
         mp3headerinfo(&info, header);
+
+        /* See if this really is a VBR file */
+        if(last_bitrate && info.bitrate != last_bitrate)
+        {
+            is_vbr = true;
+        }
+        last_bitrate = info.bitrate;
+        
         buf_seek(fd, info.frame_size-4);
         num_frames++;
         if(progressfunc)
@@ -583,8 +591,14 @@ int count_mp3_frames(int fd, int startpos, int filesize,
         }
     }
     DEBUGF("Total number of frames: %d\n", num_frames);
-    
-    return num_frames;
+
+    if(is_vbr)
+        return num_frames;
+    else
+    {
+        DEBUGF("Not a VBR file\n");
+        return 0;
+    }
 }
 
 int create_xing_header(int fd, int startpos, int filesize,
diff --git a/firmware/mpeg.c b/firmware/mpeg.c
index 13c4b01b8a..9528ede0ec 100644
--- a/firmware/mpeg.c
+++ b/firmware/mpeg.c
@@ -3030,42 +3030,49 @@ int mpeg_create_xing_header(char *filename, void (*progressfunc)(int))
         progressfunc(0);
 
     num_frames = count_mp3_frames(fd, entry.first_frame_offset,
-                                  flen,
-                                  progressfunc);
+                                  flen, progressfunc);
 
-    create_xing_header(fd, entry.first_frame_offset,
-                       flen, xingbuf, num_frames, progressfunc, true);
-
-    /* Try to fit the Xing header first in the stream. Replace the existing
-       Xing header if there is one, else see if there is room between the
-       ID3 tag and the first MP3 frame. */
-    if(entry.vbr_header_pos)
-    {
-        /* Reuse existing Xing header */
-        fpos = entry.vbr_header_pos;
-
-        DEBUGF("Reusing Xing header at %d\n", fpos);
-    }
-    else
+    if(num_frames)
     {
-        /* Any room between ID3 tag and first MP3 frame? */
-        if(entry.first_frame_offset - entry.id3v2len > 417)
+        create_xing_header(fd, entry.first_frame_offset,
+                           flen, xingbuf, num_frames, progressfunc, true);
+        
+        /* Try to fit the Xing header first in the stream. Replace the existing
+           Xing header if there is one, else see if there is room between the
+           ID3 tag and the first MP3 frame. */
+        if(entry.vbr_header_pos)
         {
-            fpos = entry.first_frame_offset - 417;
+            /* Reuse existing Xing header */
+            fpos = entry.vbr_header_pos;
+            
+            DEBUGF("Reusing Xing header at %d\n", fpos);
         }
         else
         {
-            close(fd);
-            return -3;
+            /* Any room between ID3 tag and first MP3 frame? */
+            if(entry.first_frame_offset - entry.id3v2len > 417)
+            {
+                fpos = entry.first_frame_offset - 417;
+            }
+            else
+            {
+                close(fd);
+                return -3;
+            }
         }
+        
+        lseek(fd, fpos, SEEK_SET);
+        write(fd, xingbuf, 417);
+        close(fd);
+        
+        if(progressfunc)
+            progressfunc(100);
+        return 0;
+    }
+    else
+    {
+        /* Not a VBR file */
+        DEBUGF("Not a VBR file\n");
+        return -9;
     }
-
-    lseek(fd, fpos, SEEK_SET);
-    write(fd, xingbuf, 417);
-    close(fd);
-
-    if(progressfunc)
-        progressfunc(100);
-
-    return 0;
 }
-- 
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