occasional mp3 click noises fixed

[libpicofe.git] / common / mp3_helix.c

diff --git a/common/mp3_helix.c b/common/mp3_helix.c
index 3e75ab9..f28abda 100644 (file)
--- a/common/mp3_helix.c
+++ b/common/mp3_helix.c
@@ -15,13 +15,40 @@ static HMP3Decoder mp3dec = 0;
 static int mp3_buffer_offs = 0;
 
 
+static int find_sync_word(unsigned char *buf, int nBytes)
+{
+       unsigned char *p, *pe;
+
+       /* find byte-aligned syncword - need 12 (MPEG 1,2) or 11 (MPEG 2.5) matching bits */
+       for (p = buf, pe = buf + nBytes - 4; p < pe; p++)
+       {
+               int pn;
+               if (p[0] != 0xff) continue;
+               pn = p[1];
+               if ((pn & 0xf8) != 0xf8 || // currently must be MPEG1
+                   (pn & 6) == 0) {       // invalid layer
+                       p++; continue;
+               }
+               pn = p[2];
+               if ((pn & 0xf0) < 0x20 || (pn & 0xf0) == 0xf0 || // bitrates
+                   (pn & 0x0c) != 0) { // not 44kHz
+                       continue;
+               }
+
+               return p - buf;
+       }
+
+       return -1;
+}
+
+
 static int try_get_header(unsigned char *buff, MP3FrameInfo *fi)
 {
        int ret, offs1, offs = 0;
 
        while (1)
        {
-               offs1 = MP3FindSyncWord(buff + offs, 2048 - offs);
+               offs1 = find_sync_word(buff + offs, 2048 - offs);
                if (offs1 < 0) return -2;
                offs += offs1;
                if (2048 - offs < 4) return -3;
@@ -44,7 +71,8 @@ int mp3_get_bitrate(FILE *f, int len)
 
        memset(buff, 0, 2048);
 
-       if (!mp3dec) mp3dec = MP3InitDecoder();
+       if (mp3dec) MP3FreeDecoder(mp3dec);
+       mp3dec = MP3InitDecoder();
 
        fseek(f, 0, SEEK_SET);
        ret = fread(buff, 1, 2048, f);
@@ -81,11 +109,12 @@ static int mp3_decode(void)
        unsigned char *readPtr = mp3_mem + mp3_offs;
        int bytesLeft = shared_ctl->mp3_len - mp3_offs;
        int offset; // frame offset from readPtr
-       int err;
+       int retries = 0, err;
 
        if (bytesLeft <= 0) return 1; // EOF, nothing to do
 
-       offset = MP3FindSyncWord(readPtr, bytesLeft);
+retry:
+       offset = find_sync_word(readPtr, bytesLeft);
        if (offset < 0) {
                shared_ctl->mp3_offs = shared_ctl->mp3_len;
                return 1; // EOF
@@ -102,6 +131,9 @@ static int mp3_decode(void)
                        // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
                        // just try to skip the offending frame..
                        readPtr++;
+                       bytesLeft--;
+                       if (retries++ < 2) goto retry;
+                       else lprintf("mp3 decode failed with %i after %i retries\n", err, retries);
                }
                shared_ctl->mp3_errors++;
                shared_ctl->mp3_lasterr = err;
@@ -112,6 +144,10 @@ static int mp3_decode(void)
 
 void mp3_start_local(void)
 {
+       // must re-init decoder for new track
+       if (mp3dec) MP3FreeDecoder(mp3dec);
+       mp3dec = MP3InitDecoder();
+
        mp3_buffer_offs = 0;
        mp3_decode();
 }
@@ -138,9 +174,9 @@ static int mp3_decode(void)
                fseek(mp3_current_file, mp3_file_pos, SEEK_SET);
                bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), mp3_current_file);
 
-               offset = MP3FindSyncWord(mp3_input_buffer, bytesLeft);
+               offset = find_sync_word(mp3_input_buffer, bytesLeft);
                if (offset < 0) {
-                       //lprintf("MP3FindSyncWord (%i/%i) err %i\n", mp3_file_pos, mp3_file_len, offset);
+                       //lprintf("find_sync_word (%i/%i) err %i\n", mp3_file_pos, mp3_file_len, offset);
                        mp3_file_pos = mp3_file_len;
                        return 1; // EOF
                }
@@ -179,6 +215,10 @@ void mp3_start_play(FILE *f, int pos)
        mp3_current_file = NULL;
        mp3_buffer_offs = 0;
 
+       // must re-init decoder for new track
+       if (mp3dec) MP3FreeDecoder(mp3dec);
+       mp3dec = MP3InitDecoder();
+
        if (!(PicoOpt&POPT_EN_MCD_CDDA) || f == NULL) // cdda disabled or no file?
                return;