Improvements for vbrfix plugin:

* Properly account for ID3v1 tags
 * Play time computation fixes
 * Add speech feedback

Patch by Igor Poretsky

Change-Id: Ia6df8fb171882a88527cfa9d3b76b705f09becdd

lib/rbcodec/metadata/id3tags.c

@@ -1134,6 +1134,29 @@ void setid3v2title(int fd, struct mp3entry *entry)
     }
 }
 
+/*
+ * Calculates the size of the ID3v1 tag if any.
+ *
+ * Arguments: file - the file to search for a tag.
+ *
+ * Returns: the size of the tag or 0 if none was found
+ */
+int getid3v1len(int fd)
+{
+    char buf[4];
+
+    if (-1 == lseek(fd, -128, SEEK_END))
+        return 0;
+
+    if (read(fd, buf, 3) != 3)
+        return 0;
+
+    if (strncmp(buf, "TAG", 3))
+        return 0;
+
+    return 128;
+}
+
 /*
  * Calculates the size of the ID3v2 tag.
  *

lib/rbcodec/metadata/metadata_parsers.h

@@ -22,6 +22,7 @@
 #if CONFIG_CODEC == SWCODEC
 char* id3_get_num_genre(unsigned int genre_num);
 #endif
+int getid3v1len(int fd);
 int getid3v2len(int fd);
 bool setid3v1title(int fd, struct mp3entry *entry);
 void setid3v2title(int fd, struct mp3entry *entry);

lib/rbcodec/metadata/mp3.c

@@ -71,7 +71,9 @@ static int getsonglength(int fd, struct mp3entry *entry)
     if(bytecount < 0)
         return -1;
 
-    bytecount += entry->id3v2len;
+    /* Subtract the meta information from the file size to get
+       the true size of the MP3 stream */
+    entry->filesize -= entry->id3v1len + entry->id3v2len;
 
     /* Validate byte count, in case the file has been edited without
      * updating the header.
@@ -99,6 +101,9 @@ static int getsonglength(int fd, struct mp3entry *entry)
         }
     }
 
+    entry->filesize -= bytecount;
+    bytecount += entry->id3v2len;
+
     entry->bitrate   = info.bitrate;
     entry->frequency = info.frequency;
     entry->layer     = info.layer;
@@ -127,7 +132,7 @@ static int getsonglength(int fd, struct mp3entry *entry)
         if (info.bitrate < 8)
             filetime = 0;
         else
-            filetime = (entry->filesize - bytecount) / (info.bitrate / 8);
+            filetime = entry->filesize / (info.bitrate >> 3);
         /* bitrate is in kbps so this delivers milliseconds. Doing bitrate / 8
          * instead of filesize * 8 is exact, because mpeg audio bitrates are
          * always multiples of 8, and it avoids overflows. */
@@ -163,6 +168,7 @@ bool get_mp3_metadata(int fd, struct mp3entry *entry)
 {
     entry->title = NULL;
     entry->filesize = filesize(fd);
+    entry->id3v1len = getid3v1len(fd);
     entry->id3v2len = getid3v2len(fd);
     entry->tracknum = 0;
     entry->discnum = 0;
@@ -174,10 +180,6 @@ bool get_mp3_metadata(int fd, struct mp3entry *entry)
         return false;
     entry->length = len;
 
-    /* Subtract the meta information from the file size to get
-       the true size of the MP3 stream */
-    entry->filesize -= entry->first_frame_offset;
-
     /* only seek to end of file if no id3v2 tags were found */
     if (!entry->id3v2len) {
         setid3v1title(fd, entry);

lib/rbcodec/metadata/mp3data.c

@@ -39,6 +39,9 @@
 #include "mp3data.h"
 #include "platform.h"
 
+#include "metadata.h"
+#include "metadata/metadata_parsers.h"
+
 //#define DEBUG_VERBOSE
 
 #ifdef DEBUG_VERBOSE
@@ -340,7 +343,7 @@ static int buf_getbyte(int fd, unsigned char *c)
 static int buf_seek(int fd, int len)
 {
     fnf_read_index += len;
-    if(fnf_read_index > fnf_buf_len)
+    if(fnf_read_index >= fnf_buf_len)
     {
         len = fnf_read_index - fnf_buf_len;
         
@@ -348,23 +351,22 @@ static int buf_seek(int fd, int len)
         if(fnf_buf_len < 0)
             return -1;
 
-        fnf_read_index = 0;
-        fnf_read_index += len;
+        fnf_read_index = len;
     }
     
-    if(fnf_read_index > fnf_buf_len)
+    if(fnf_read_index >= fnf_buf_len)
     {
         return -1;
     }
-    else
-        return 0;
+
+    return 0;
 }
 
 static void buf_init(unsigned char* buf, size_t buflen)
 {
     fnf_buf = buf;
     fnf_buf_len = buflen;
-    fnf_read_index = 0;
+    fnf_read_index = buflen;
 }
 
 static unsigned long buf_find_next_frame(int fd, long *offset, long max_offset)
@@ -601,14 +603,18 @@ int get_mp3file_info(int fd, struct mp3info *info)
     }
     else
     {
+        long offset;
+
         VDEBUGF("-- No VBR header --\n");
         
         /* There was no VBR header found. So, we seek back to beginning and
          * search for the first MPEG frame header of the mp3 stream. */
-        lseek(fd, -info->frame_size, SEEK_CUR);
+        offset = lseek(fd, -info->frame_size, SEEK_CUR);
         result = get_next_header_info(fd, &bytecount, info, false);
         if(result)
             return result;
+
+        info->byte_count = filesize(fd) - getid3v1len(fd) - offset - bytecount;
     }
 
     return bytecount;
@@ -647,7 +653,7 @@ int count_mp3_frames(int fd,  int startpos,  int filesize,
     num_frames = 0;
     cnt = 0;
     
-    while((header = buf_find_next_frame(fd, &bytes, header_template))) {
+    while((header = buf_find_next_frame(fd, &bytes, startpos + filesize))) {
         mp3headerinfo(&info, header);
 
         if(!header_template)
@@ -723,7 +729,7 @@ int create_xing_header(int fd, long startpos, long filesize,
             /* Advance from the last seek point to this one */
             for(j = 0;j < pos - last_pos;j++)
             {
-                header = buf_find_next_frame(fd, &bytes, header_template);
+                header = buf_find_next_frame(fd, &bytes, startpos + filesize);
                 filepos += bytes;
                 mp3headerinfo(&info, header);
                 buf_seek(fd, info.frame_size-4);