ref: 54dcc13cc3bae0b07d5f5d52c0d0efbcd5b833fb
parent: 5feb180ca214f0944f8c4a5d42b688020e7ac0c0
author: Sigrid Solveig Haflínudóttir <ftrvxmtrx@gmail.com>
date: Mon Jun 1 10:11:32 EDT 2020
add opus support
--- a/README.md
+++ b/README.md
@@ -11,6 +11,7 @@
| Ogg/Vorbis | yes | no | yes |
| FLAC | yes | no | yes |
| m4a | yes | no | yes |
+| opus | yes | no | yes |
| replay gain | yes | no | ??? |
| size | tiny | bloated | more bloated |
| license | PPL | LGPL | LGPL/MPL |
--- a/mkfile
+++ b/mkfile
@@ -8,6 +8,7 @@
id3v1.$O\
id3v2.$O\
m4a.$O\
+ opus.$O\
tags.$O\
utf16.$O\
vorbis.$O\
--- /dev/null
+++ b/opus.c
@@ -1,0 +1,93 @@
+#include "tagspriv.h"
+
+#define leuint(d) (uint)(((uchar*)(d))[3]<<24 | ((uchar*)(d))[2]<<16 | ((uchar*)(d))[1]<<8 | ((uchar*)(d))[0]<<0)
+
+int
+tagopus(Tagctx *ctx)
+{+ char *v;
+ uchar *d, h[4];
+ int sz, numtags, i, npages;
+
+ d = (uchar*)ctx->buf;
+ /* need to find vorbis frame with type=3 */
+ for(npages = 0; npages < 2; npages++){ /* vorbis comment is the second header */+ int nsegs;
+ if(ctx->read(ctx, d, 27) != 27)
+ return -1;
+ if(memcmp(d, "OggS", 4) != 0)
+ return -1;
+
+ /* calculate the size of the packet */
+ nsegs = d[26];
+ if(ctx->read(ctx, d, nsegs+8) != nsegs+8)
+ return -1;
+ for(sz = i = 0; i < nsegs; sz += d[i++]);
+
+ if(memcmp(&d[nsegs], "OpusHead", 8) == 0){+ if(ctx->read(ctx, d, 8) != 8 || d[0] != 1)
+ return -1;
+ sz -= 8;
+ ctx->channels = d[1];
+ ctx->samplerate = leuint(&d[4]);
+ }else if(memcmp(&d[nsegs], "OpusTags", 8) == 0){+ break;
+ }
+
+ ctx->seek(ctx, sz-8, 1);
+ }
+
+ if(npages < 3){+ if(ctx->read(ctx, d, 4) != 4)
+ return -1;
+ sz = leuint(d);
+ if(ctx->seek(ctx, sz, 1) < 0 || ctx->read(ctx, h, 4) != 4)
+ return -1;
+ numtags = leuint(h);
+
+ for(i = 0; i < numtags; i++){+ if(ctx->read(ctx, h, 4) != 4)
+ return -1;
+ if((sz = leuint(h)) < 0)
+ return -1;
+
+ if(ctx->bufsz < sz+1){+ if(ctx->seek(ctx, sz, 1) < 0)
+ return -1;
+ continue;
+ }
+ if(ctx->read(ctx, ctx->buf, sz) != sz)
+ return -1;
+ ctx->buf[sz] = 0;
+
+ if((v = strchr(ctx->buf, '=')) == nil)
+ return -1;
+ *v++ = 0;
+ cbvorbiscomment(ctx, ctx->buf, v);
+ }
+ }
+
+ /* calculate the duration */
+ if(ctx->samplerate > 0){+ sz = ctx->bufsz <= 4096 ? ctx->bufsz : 4096;
+ for(i = sz; i < 65536+16; i += sz - 16){+ if(ctx->seek(ctx, -i, 2) <= 0)
+ break;
+ v = ctx->buf;
+ if(ctx->read(ctx, v, sz) != sz)
+ break;
+ for(; v != nil && v < ctx->buf+sz;){+ v = memchr(v, 'O', ctx->buf+sz - v - 14);
+ if(v != nil && v[1] == 'g' && v[2] == 'g' && v[3] == 'S' && (v[5] & 4) == 4){ /* last page */+ uvlong g = leuint(v+6) | (uvlong)leuint(v+10)<<32;
+ ctx->duration = g * 1000 / ctx->samplerate;
+ return 0;
+ }
+ if(v != nil)
+ v++;
+ }
+ }
+ }
+
+ return 0;
+}
--- a/tags.c
+++ b/tags.c
@@ -13,6 +13,7 @@
extern int tagid3v2(Tagctx *ctx);
extern int tagid3v1(Tagctx *ctx);
extern int tagm4a(Tagctx *ctx);
+extern int tagopus(Tagctx *ctx);
static const Getter g[] =
{@@ -21,6 +22,7 @@
{tagvorbis, Fogg}, {tagflac, Fflac}, {tagm4a, Fm4a},+ {tagopus, Fopus},};
void
--- a/tags.h
+++ b/tags.h
@@ -30,6 +30,7 @@
Fogg,
Fflac,
Fm4a,
+ Fopus,
};
/* Tag parser context. You need to set it properly before parsing an audio file using libtags. */