3 files changed, 59 insertions, 25 deletions

diff --git a/apps/playback.c b/apps/playback.c
index c91a3a8155..df0353b1d6 100644
--- a/apps/playback.c
+++ b/apps/playback.c
@@ -125,19 +125,19 @@ static volatile int buf_widx;
 
 #define MAX_TRACK 10
 struct track_info {
-    struct mp3entry id3;
-    struct mp3info mp3data;
-    char *codecbuf;
-    size_t codecsize;
-    int codectype;
-    
-    volatile char *filebuf;
-    off_t filerem;
-    off_t filesize;
-    off_t filepos;
-    volatile int available;
-    bool taginfo_ready;
-    int playlist_offset;
+    struct mp3entry id3;     /* TAG metadata */
+    struct mp3info mp3data;  /* MP3 metadata */
+    char *codecbuf;          /* Pointer to codec buffer */
+    size_t codecsize;        /* Codec length in bytes */
+    int codectype;           /* Codec type (example AFMT_MPA_L3) */
+    
+    off_t filerem;           /* Remaining bytes of file NOT in buffer */
+    off_t filesize;          /* File total length */
+    off_t filepos;           /* Read position of file for next buffer fill */
+    off_t start_pos;         /* Position to first bytes of file in buffer */
+    volatile int available;  /* Available bytes to read from buffer */
+    bool taginfo_ready;      /* Is metadata read */
+    int playlist_offset;     /* File location in playlist */
 };
 
 /* Track information (count in file buffer, read/write indexes for
@@ -286,7 +286,11 @@ void codec_advance_buffer_callback(size_t amount)
         
     if ((int)amount > cur_ti->available) {
         codecbufused = 0;
-        buf_ridx = buf_widx;
+        buf_ridx = 0;
+        buf_widx = 0;
+        cur_ti->start_pos += amount;
+        amount -= cur_ti->available;
+        ci.curpos += cur_ti->available;
         cur_ti->available = 0;
         while ((int)amount < cur_ti->available && !ci.stop_codec)
             yield();
@@ -343,7 +347,8 @@ bool codec_seek_buffer_callback(off_t newpos)
     if (ci.curpos - difference < 0)
         difference = ci.curpos;
     
-    if (codecbufused + difference > codecbuflen) {
+    if (ci.curpos - difference < cur_ti->start_pos) {
+        logf("Seek failed (reload song)");
         /* We need to reload the song. FIX THIS! */
         return false;
     }
@@ -473,8 +478,9 @@ void audio_fill_file_buffer(void)
         fill_bytesleft -= rc;
     }
     
-    tracks[track_widx].filerem -= i;
     codecbufused += i;
+    tracks[track_widx].filerem -= i;
+    tracks[track_widx].start_pos = tracks[track_widx].filepos;
     tracks[track_widx].filepos += i;
     logf("Done:%d", tracks[track_widx].available);
     if (tracks[track_widx].filerem == 0) {
@@ -653,7 +659,8 @@ bool audio_load_track(int offset, bool start_play, int peek_offset)
         close(fd);
         return false;
     }
-    tracks[track_widx].filebuf = &codecbuf[buf_widx];
+    // tracks[track_widx].filebuf = &codecbuf[buf_widx];
+    tracks[track_widx].start_pos = 0;
         
     //logf("%s", trackname);
     logf("Buffering track:%d/%d", track_widx, track_ridx);
@@ -681,6 +688,7 @@ bool audio_load_track(int offset, bool start_play, int peek_offset)
             tracks[track_widx].filepos = offset;
             tracks[track_widx].filerem = tracks[track_widx].filesize - offset;
             ci.curpos = offset;
+            tracks[track_widx].start_pos = offset;
         } else {
             lseek(fd, 0, SEEK_SET);
         }
@@ -943,7 +951,7 @@ bool audio_load_track(int offset, bool start_play, int peek_offset)
     
     track_changed = true;
     track_count++;
-    i = tracks[track_widx].filepos;
+    i = tracks[track_widx].start_pos;
     while (i < size) {
         /* Give codecs some processing time to prevent glitches. */
         yield_codecs();
diff --git a/apps/playback.h b/apps/playback.h
index 18f92488fa..4cdece75c9 100644
--- a/apps/playback.h
+++ b/apps/playback.h
@@ -20,6 +20,7 @@
 #ifndef _AUDIO_H
 #define _AUDIO_H
 
+/* Supported file types. */
 #define AFMT_MPA_L1      0x0001  // MPEG Audio layer 1
 #define AFMT_MPA_L2      0x0002  // MPEG Audio layer 2
 #define AFMT_MPA_L3      0x0004  // MPEG Audio layer 3
@@ -36,6 +37,7 @@
 #define AFMT_UNKNOWN     0x1000  // Unknown file format
 #define AFMT_WAVPACK     0x2000  // WavPack
 
+/* File buffer configuration keys. */
 #define CODEC_SET_FILEBUF_WATERMARK     1
 #define CODEC_SET_FILEBUF_CHUNKSIZE     2
 #define CODEC_SET_FILEBUF_LIMIT         3
@@ -43,32 +45,56 @@
 /* Not yet implemented. */
 #define CODEC_SET_AUDIOBUF_WATERMARK    4
 
+/* Codec Interface */
 struct codec_api {
-    off_t  filesize;
-    off_t  curpos;
-    size_t bitspersampe;
+    off_t  filesize;          /* Total file length */
+    off_t  curpos;            /* Current buffer position */
     
     /* For gapless mp3 */
-    struct mp3entry *id3;
-    struct mp3info *mp3data;
-    bool *taginfo_ready;
+    struct mp3entry *id3;     /* TAG metadata pointer */
+    struct mp3info *mp3data;  /* MP3 metadata pointer */
+    bool *taginfo_ready;      /* Is metadata read */
     
+    /* Codec should periodically check if stop_codec is set to true.
+       In case it's, codec must return with PLUGIN_OK status immediately. */
     bool stop_codec;
+    /* Codec should periodically check if reload_codec is set to true.
+       In case it's, codec should reload itself without exiting. */
     bool reload_codec;
+    /* If seek_time != 0, codec should seek to that song position (in ms)
+       if codec supports seeking. */
     int seek_time;
     
+    /* Returns buffer to malloc array. Only codeclib should need this. */
     void* (*get_codec_memory)(size_t *size);
+    /* Insert PCM data into audio buffer for playback. Playback will start
+       automatically. */
     bool (*audiobuffer_insert)(char *data, size_t length);
+    /* Set song position in WPS (value in ms). */
     void (*set_elapsed)(unsigned int value);
     
+    /* Read next <size> amount bytes from file buffer to <ptr>.
+       Will return number of bytes read or 0 if end of file. */
     size_t (*read_filebuf)(void *ptr, size_t size);
+    /* Request pointer to file buffer which can be used to read
+       <realsize> amount of data. <reqsize> tells the buffer system
+       how much data it should try to allocate. If <realsize> is 0,
+       end of file is reached. */
     void* (*request_buffer)(size_t *realsize, size_t reqsize);
+    /* Advance file buffer position by <amount> amount of bytes. */
     void (*advance_buffer)(size_t amount);
+    /* Advance file buffer to a pointer location inside file buffer. */
     void (*advance_buffer_loc)(void *ptr);
+    /* Seek file buffer to position <newpos> beginning of file. */
     bool (*seek_buffer)(off_t newpos);
+    /* Calculate mp3 seek position from given time data in ms. */
     off_t (*mp3_get_filepos)(int newtime);
+    /* Request file change from file buffer. Returns true is next
+       track is available and changed. If return value is false,
+       codec should exit immediately with PLUGIN_OK status. */
     bool (*request_next_track)(void);
     
+    /* Configure different codec buffer parameters. */
     void (*configure)(int setting, void *value);
 };
 
diff --git a/apps/plugins/codecmpa.c b/apps/plugins/codecmpa.c
index b152f2cb3e..67062bc40b 100644
--- a/apps/plugins/codecmpa.c
+++ b/apps/plugins/codecmpa.c
@@ -305,12 +305,12 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
         sample_loc = ci->seek_time/1000 * ci->id3->frequency;
         newpos = ci->mp3_get_filepos(ci->seek_time-1);
         if (ci->seek_buffer(newpos)) {
-            ci->seek_time = 0;
             if (sample_loc >= samplecount + samplesdone)
                 break ;
             samplecount += samplesdone - sample_loc;
             samplesdone = sample_loc;
         }
+        ci->seek_time = 0;
     }
 
     /* Lock buffers */