support mp3 decoding over libavcodec
[picodrive.git] / platform / common / mp3_helix.c
index 8ff66d8..62e9189 100644 (file)
 #include "mp3.h"
 #include "lprintf.h"
 
-static HMP3Decoder mp3dec = 0;
-static FILE *mp3_current_file = NULL;
-static int mp3_file_len = 0, mp3_file_pos = 0;
-static int mp3_buffer_offs = 0;
-static unsigned char mp3_input_buffer[2*1024];
+static HMP3Decoder mp3dec;
+static unsigned char mp3_input_buffer[2 * 1024];
 
 #ifdef __GP2X__
 #define mp3_update mp3_update_local
 #define mp3_start_play mp3_start_play_local
 #endif
 
-static int try_get_header(unsigned char *buff, MP3FrameInfo *fi)
-{
-       int ret, offs1, offs = 0;
-
-       while (1)
-       {
-               offs1 = mp3_find_sync_word(buff + offs, 2048 - offs);
-               if (offs1 < 0) return -2;
-               offs += offs1;
-               if (2048 - offs < 4) return -3;
-
-               // printf("trying header %08x\n", *(int *)(buff + offs));
-
-               ret = MP3GetNextFrameInfo(mp3dec, fi, buff + offs);
-               if (ret == 0 && fi->bitrate != 0) break;
-               offs++;
-       }
-
-       return ret;
-}
-
-int mp3_get_bitrate(void *f_, int len)
-{
-       unsigned char buff[2048];
-       MP3FrameInfo fi;
-       FILE *f = f_;
-       int ret;
-
-       memset(buff, 0, sizeof(buff));
-
-       if (mp3dec)
-               MP3FreeDecoder(mp3dec);
-       mp3dec = MP3InitDecoder();
-
-       fseek(f, 0, SEEK_SET);
-       ret = fread(buff, 1, sizeof(buff), f);
-       fseek(f, 0, SEEK_SET);
-       if (ret <= 0)
-               return -1;
-
-       ret = try_get_header(buff, &fi);
-       if (ret != 0 || fi.bitrate == 0) {
-               // try to read somewhere around the middle
-               fseek(f, len>>1, SEEK_SET);
-               fread(buff, 1, 2048, f);
-               fseek(f, 0, SEEK_SET);
-               ret = try_get_header(buff, &fi);
-       }
-       if (ret != 0)
-               return ret;
-
-       // printf("bitrate: %i\n", fi.bitrate / 1000);
-
-       return fi.bitrate / 1000;
-}
-
-static int mp3_decode(void)
+int mp3dec_decode(FILE *f, int *file_pos, int file_len)
 {
        unsigned char *readPtr;
        int bytesLeft;
@@ -93,16 +34,17 @@ static int mp3_decode(void)
 
        do
        {
-               if (mp3_file_pos >= mp3_file_len)
+               if (*file_pos >= file_len)
                        return 1; /* EOF, nothing to do */
 
-               fseek(mp3_current_file, mp3_file_pos, SEEK_SET);
-               bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), mp3_current_file);
+               fseek(f, *file_pos, SEEK_SET);
+               bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), f);
 
                offset = mp3_find_sync_word(mp3_input_buffer, bytesLeft);
                if (offset < 0) {
-                       lprintf("find_sync_word (%i/%i) err %i\n", mp3_file_pos, mp3_file_len, offset);
-                       mp3_file_pos = mp3_file_len;
+                       lprintf("find_sync_word (%i/%i) err %i\n",
+                               *file_pos, file_len, offset);
+                       *file_pos = file_len;
                        return 1; // EOF
                }
                readPtr = mp3_input_buffer + offset;
@@ -113,112 +55,41 @@ static int mp3_decode(void)
                if (err) {
                        if (err == ERR_MP3_MAINDATA_UNDERFLOW && !had_err) {
                                // just need another frame
-                               mp3_file_pos += readPtr - mp3_input_buffer;
+                               *file_pos += readPtr - mp3_input_buffer;
                                continue;
                        }
                        if (err == ERR_MP3_INDATA_UNDERFLOW && !had_err) {
                                if (offset == 0)
                                        // something's really wrong here, frame had to fit
-                                       mp3_file_pos = mp3_file_len;
+                                       *file_pos = file_len;
                                else
-                                       mp3_file_pos += offset;
+                                       *file_pos += offset;
                                continue;
                        }
                        if (-12 <= err && err <= -6) {
                                // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
                                // just try to skip the offending frame..
-                               mp3_file_pos += offset + 1;
+                               *file_pos += offset + 1;
                                continue;
                        }
-                       lprintf("MP3Decode err (%i/%i) %i\n", mp3_file_pos, mp3_file_len, err);
-                       mp3_file_pos = mp3_file_len;
+                       lprintf("MP3Decode err (%i/%i) %i\n",
+                               *file_pos, file_len, err);
+                       *file_pos = file_len;
                        return 1;
                }
-               mp3_file_pos += readPtr - mp3_input_buffer;
+               *file_pos += readPtr - mp3_input_buffer;
        }
        while (0);
 
        return 0;
 }
 
-void mp3_start_play(void *f_, int pos)
+int mp3dec_start(void)
 {
-       FILE *f = f_;
-
-       mp3_file_len = mp3_file_pos = 0;
-       mp3_current_file = NULL;
-       mp3_buffer_offs = 0;
-
-       if (!(PicoOpt & POPT_EN_MCD_CDDA) || f == NULL) // cdda disabled or no file?
-               return;
-
        // must re-init decoder for new track
        if (mp3dec)
                MP3FreeDecoder(mp3dec);
        mp3dec = MP3InitDecoder();
 
-       mp3_current_file = f;
-       fseek(f, 0, SEEK_END);
-       mp3_file_len = ftell(f);
-
-       // search for first sync word, skipping stuff like ID3 tags
-       while (mp3_file_pos < 128*1024) {
-               int offs, bytes;
-
-               fseek(f, mp3_file_pos, SEEK_SET);
-               bytes = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), f);
-               if (bytes < 4)
-                       break;
-               offs = mp3_find_sync_word(mp3_input_buffer, bytes);
-               if (offs >= 0) {
-                       mp3_file_pos += offs;
-                       break;
-               }
-               mp3_file_pos += bytes - 2;
-       }
-
-       // seek..
-       if (pos) {
-               unsigned long long pos64 = mp3_file_len - mp3_file_pos;
-               pos64 *= pos;
-               mp3_file_pos += pos64 >> 10;
-       }
-
-       mp3_decode();
-}
-
-void mp3_update(int *buffer, int length, int stereo)
-{
-       int length_mp3, shr = 0;
-       void (*mix_samples)(int *dest_buf, short *mp3_buf, int count) = mix_16h_to_32;
-
-       if (mp3_current_file == NULL || mp3_file_pos >= mp3_file_len)
-               return; /* no file / EOF */
-
-       length_mp3 = length;
-       if (PsndRate <= 11025 + 100) {
-               mix_samples = mix_16h_to_32_s2;
-               length_mp3 <<= 2; shr = 2;
-       }
-       else if (PsndRate <= 22050 + 100) {
-               mix_samples = mix_16h_to_32_s1;
-               length_mp3 <<= 1; shr = 1;
-       }
-
-       if (1152 - mp3_buffer_offs >= length_mp3) {
-               mix_samples(buffer, cdda_out_buffer + mp3_buffer_offs*2, length<<1);
-
-               mp3_buffer_offs += length_mp3;
-       } else {
-               int ret, left = 1152 - mp3_buffer_offs;
-
-               mix_samples(buffer, cdda_out_buffer + mp3_buffer_offs*2, (left>>shr)<<1);
-               ret = mp3_decode();
-               if (ret == 0) {
-                       mp3_buffer_offs = length_mp3 - left;
-                       mix_samples(buffer + ((left>>shr)<<1), cdda_out_buffer, (mp3_buffer_offs>>shr)<<1);
-               } else
-                       mp3_buffer_offs = 0;
-       }
+       return (mp3dec == 0) ? -1 : 0;
 }
-