shithub: mcfs

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matroska: add support for header stripping with no lacing

--- a/matroska.c

+++ b/matroska.c

@@ -183,10 +183,10 @@

 int

 matroskarun(Biobuf *f)

 {

-	int isebml, npackets, i, skipdata;

-	vlong left, n, sz, bufsz, track, off, packetsz, x, endtracks;

+	int isebml, npackets, i, skipdata, lacing;

+	vlong left, n, sz, nsz, bufsz, track, off, packetsz, x, endtracks;

 	uvlong ts, timestamp, timestampscale;

-	uchar *buf;

+	uchar *buf, *b;

 	double duration;

 	Ebml e, te;

 	Elspec el;

@@ -200,6 +200,7 @@

 	te.tracknum = -1;

 	timestampscale = 1000000;

 	e.tracknum = -1;

+	e.comp.algo = -1;

 	duration = 0;

 	ts = 0;

 	skipdata = trackdump == Nodump;

@@ -257,10 +258,13 @@

 			if(e.tracknum == trackdump)

 				memmove(&te, &e, sizeof(e));

 			memset(&e, 0, sizeof(e));

+			e.comp.algo = -1;

 			e.timestampscale = timestampscale;

 			continue;

 		}else if(el.id == EVideo || el.id == EAudio){

 			continue;

+		}else if(el.id == EContentEncodings || el.id == EContentEncoding || el.id == EContentCompression){

+			continue;

 		}else if(el.id == EBlockGroup && !skipdata){

 			continue;

 		}else if((el.id == ESimpleBlock || el.id == EBlock) && !skipdata){

@@ -293,10 +297,34 @@

 				}

 				left -= sz;

 				sz -= 3;

+				lacing = (buf[2] >> 1) & 3;

 				npackets = buf[3]+1;

-				switch((buf[2] >> 1) & 3){ /* lacing */

+

+				if(te.comp.algo == 3 && lacing == 0){ /* header stripping, need to put bytes back */

+					if(te.comp.sz == 0)

+						te.comp.algo = -1;

+					else{

+						nsz = sz + npackets*te.comp.sz;

+						if(bufsz < nsz){

+							buf = realloc(buf, nsz);

+							bufsz = nsz;

+						}

+					}

+				}else if(te.comp.algo >= 0){

+					werrstr("unsupported: comp algo %d, lacing %d, please report a bug", te.comp.algo, lacing);

+					goto err;

+				}

+

+				b = buf+3;

+				switch(lacing){ /* lacing */

 				case 0: /* none */

-					packets[0].data = buf+3;

+					if(te.comp.algo == 3){

+						b = buf;

+						memmove(b+te.comp.sz, b+3, sz);

+						memmove(b, te.comp.data, te.comp.sz);

+						sz += te.comp.sz;

+					}

+					packets[0].data = b;

 					packets[0].sz = sz;

 					npackets = 1;

 					break;

@@ -385,6 +413,10 @@

 				getbytes(ECodecPrivate, e.codec.priv)

 			else

 				getnumber(ECodecDelay, e.codec.delay)

+			else

+				getnumber(EContentCompAlgo, e.comp.algo)

+			else

+				getbytes(EContentCompSettings, e.comp)

 			else

 				getnumber(EPixelWidth, e.video.width)

 			else

--- a/packet.h

+++ b/packet.h

@@ -22,6 +22,11 @@

 			int sz;

 		}priv;

 	}codec;

+	struct {

+		uchar *data;

+		int sz;

+		int algo;

+	}comp;

 	u32int trackuid;

 	u32int fmt;