From 73a71a4712795cef91849bd1eef327ac68ef19db Mon Sep 17 00:00:00 2001
From: Nicolas Pennequin <nicolas.pennequin@free.fr>
Date: Thu, 3 Apr 2008 12:13:03 +0000
Subject: Move audio_set_elapsed to mpa.c, as recommended by the TODO note.
 Please correct me if affecting ci->id3->elapsed directly (ie without using
 ci->set_elapsed) is wrong.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16945 a1c6a512-1295-4272-9138-f99709370657
---
 apps/codecs/mpa.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

(limited to 'apps/codecs/mpa.c')

diff --git a/apps/codecs/mpa.c b/apps/codecs/mpa.c
index f9a27f5b41..a18a5e8090 100644
--- a/apps/codecs/mpa.c
+++ b/apps/codecs/mpa.c
@@ -109,6 +109,61 @@ int get_file_pos(int newtime)
     return pos;
 }
 
+static void set_elapsed(struct mp3entry* id3)
+{
+    unsigned long offset = id3->offset > id3->first_frame_offset ?
+        id3->offset - id3->first_frame_offset : 0;
+
+    if ( id3->vbr ) {
+        if ( id3->has_toc ) {
+            /* calculate elapsed time using TOC */
+            int i;
+            unsigned int remainder, plen, relpos, nextpos;
+
+            /* find wich percent we're at */
+            for (i=0; i<100; i++ )
+                if ( offset < id3->toc[i] * (id3->filesize / 256) )
+                    break;
+
+            i--;
+            if (i < 0)
+                i = 0;
+
+            relpos = id3->toc[i];
+
+            if (i < 99)
+                nextpos = id3->toc[i+1];
+            else
+                nextpos = 256;
+
+            remainder = offset - (relpos * (id3->filesize / 256));
+
+            /* set time for this percent (divide before multiply to prevent
+               overflow on long files. loss of precision is negligible on
+               short files) */
+            id3->elapsed = i * (id3->length / 100);
+
+            /* calculate remainder time */
+            plen = (nextpos - relpos) * (id3->filesize / 256);
+            id3->elapsed += (((remainder * 100) / plen) *
+                             (id3->length / 10000));
+        }
+        else {
+            /* no TOC exists. set a rough estimate using average bitrate */
+            int tpk = id3->length /
+                ((id3->filesize - id3->first_frame_offset - id3->id3v1len) /
+                1024);
+            id3->elapsed = offset / 1024 * tpk;
+        }
+    }
+    else
+    {
+        /* constant bitrate, use exact calculation */
+        if (id3->bitrate != 0)
+            id3->elapsed = offset / (id3->bitrate / 8);
+    }
+}
+
 /* this is the codec entry point */
 enum codec_status codec_main(void)
 {
@@ -145,8 +200,10 @@ next_track:
     current_frequency = ci->id3->frequency;
     codec_set_replaygain(ci->id3);
     
-    if (ci->id3->offset)
+    if (ci->id3->offset) {
         ci->seek_buffer(ci->id3->offset);
+        set_elapsed(ci->id3);
+    }
     else
         ci->seek_buffer(ci->id3->first_frame_offset);
 
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