2 files changed, 17 insertions(+), 3 deletions(-)

M ogg.c
M packet.h

@@ 13,6 13,14 @@ packet(Biobuf *out, Packetctx *ctx, int htype, Packet *p, int np, uvlong granule
 	u32int crc;
 	int psz, i, n, ntot, ip;
 
+	if(ctx->frid == 0 && ctx->fmt == FmtTheora && np > 0 && p->sz > 41){
+		if(memcmp(p->data, "\x80theora", 7) != 0){
+			werrstr("invalid Theora packet");
+			return -1;
+		}
+		ctx->kfgshift = ((p->data[40]<<8 | p->data[41]) >> 5) & 0x1f;
+	}
+
 	h[5] = htype;
 	h[6] = granule;
 	h[7] = granule >> 8;


@@ 131,7 139,12 @@ oggpacket(Biobuf *out, Packetctx *ctx, Packet *p, int np, uvlong ts, int key)
 	}
 
 	if(ctx->fmt == FmtTheora){
-		gr = 0;
+		ctx->nonkey++; /* FIXME VREV 1 vs 0 diff here, to make it work with 0 */
+		if(key){
+			ctx->key += ctx->nonkey;
+			ctx->nonkey = 0;
+		}
+		gr = (uvlong)ctx->key<<ctx->kfgshift | ctx->nonkey;
 	}else{
 		gr = (ts * 48) / 1000000;
 	}

@@ 30,8 30,6 @@ struct Packetctx {
 	u32int trackuid;
 	u32int fmt;
 
-	int key;
-
 	struct {
 		int width;
 		int height;


@@ 50,6 48,9 @@ struct Packetctx {
 		int n;
 	}ps[16];
 	int nps;
+	int key;
+	int nonkey;
+	int kfgshift;
 };
 
 int aacpacket(Biobuf *out, Packetctx *ctx, Packet *p, int np, uvlong ts, int key);