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Parse the metadata in a FLAC file to populate the "id3" struct (currently only length, samplerate etc)

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6627 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Dave Chapman 2005-06-09 00:23:50 +00:00
parent 2d8e7f20d4
commit 1971ee6765
1 changed files with 67 additions and 0 deletions
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67
apps/playback.c
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@ -572,6 +572,9 @@ bool audio_load_track(int offset, bool start_play, int peek_offset)
off_t size;
int rc, i;
int copy_n;
/* Used by the FLAC metadata parser */
unsigned long totalsamples;
unsigned char* buf;
if (track_count >= MAX_TRACK)
return false;
@ -638,6 +641,70 @@ bool audio_load_track(int offset, bool start_play, int peek_offset)
tracks[track_widx].taginfo_ready = true;
break ;
case AFMT_FLAC:
/* A simple parser to read vital metadata from a FLAC file - length, frequency, bitrate etc. */
/* This code should either be moved to a seperate file, or discarded in favour of the libFLAC code */
/* The FLAC stream specification can be found at http://flac.sourceforge.net/format.html#stream */
/* Use the trackname part of the id3 structure as a temporary buffer */
buf=tracks[track_widx].id3.path;
lseek(fd, 0, SEEK_SET);
rc = read(fd, buf, 4);
if (rc < 4) {
close(fd);
return false;
}
if (memcmp(buf,"fLaC",4)!=0) {
logf("%s is not a FLAC file\n",trackname);
close(fd);
return(false);
}
while (1) {
rc = read(fd, buf, 4);
i = (buf[1]<<16)|(buf[2]<<8)|buf[3]; /* The length of the block */
if ((buf[0]&0x7f)==0) { /* 0 is the STREAMINFO block */
rc = read(fd, buf, i); /* FIXME: Don't trust the value of i */
if (rc < 0) {
close(fd);
return false;
}
tracks[track_widx].id3.vbr=true; /* All FLAC files are VBR */
tracks[track_widx].id3.filesize=filesize(fd);
tracks[track_widx].id3.frequency=(buf[10]<<12)|(buf[11]<<4)|((buf[12]&0xf0)>>4);
/* NOT NEEDED: bitspersample=(((buf[12]&0x01)<<4)|((buf[13]&0xf0)>>4))+1; */
/* totalsamples is a 36-bit field, but we assume <= 32 bits are used */
totalsamples=(buf[14]<<24)|(buf[15]<<16)|(buf[16]<<8)|buf[17];
/* Calculate track length (in ms) and estimate the bitrate (in kbit/s) */
tracks[track_widx].id3.length=(totalsamples/tracks[track_widx].id3.frequency)*1000;
tracks[track_widx].id3.bitrate=(filesize(fd)*8)/tracks[track_widx].id3.length;
} else if ((buf[0]&0x7f)==4) { /* 4 is the VORBIS_COMMENT block */
/* The next i bytes of the file contain the VORBIS COMMENTS - just skip them for now. */
lseek(fd, i, SEEK_CUR);
} else {
if (buf[0]&0x80) { /* If we have reached the last metadata block, abort. */
break;
} else {
lseek(fd, i, SEEK_CUR); /* Skip to next metadata block */
}
}
}
lseek(fd, 0, SEEK_SET);
strncpy(tracks[track_widx].id3.path,trackname,sizeof(tracks[track_widx].id3.path));
tracks[track_widx].taginfo_ready = true;
break;
/* If we don't know how to read the metadata, just store the filename */
default:
strncpy(tracks[track_widx].id3.path,trackname,sizeof(tracks[track_widx].id3.path));