[asterisk-commits] rizzo: branch rizzo/video_v2 r85354 - /team/rizzo/video_v2/channels/

[SVN commits to the Asterisk project]

Author: rizzo
Date: Wed Oct 10 15:36:53 2007
New Revision: 85354

URL: http://svn.digium.com/view/asterisk?view=rev&rev=85354
Log:
more code cleanup

Modified:
    team/rizzo/video_v2/channels/console_video.c

Modified: team/rizzo/video_v2/channels/console_video.c
URL: http://svn.digium.com/view/asterisk/team/rizzo/video_v2/channels/console_video.c?view=diff&rev=85354&r1=85353&r2=85354
==============================================================================
--- team/rizzo/video_v2/channels/console_video.c (original)
+++ team/rizzo/video_v2/channels/console_video.c Wed Oct 10 15:36:53 2007
@@ -512,23 +512,6 @@
 	return first;
 }
 
-#define MAKE_MASK(bits)                ( (1<<(bits)) -1 )
-
-/*
- * Get the P flag from the H.263+ header from the RTP payload (see RFC 2429).
- */
-static inline unsigned int rfc2429_get_P(const uint8_t *header){
-	return (header[0]>>2) & 0x1;
-}
-
-/*
- * Get the PLEN variable from the H.263+ header from the RTP payload (see RFC 2429).
- */
-static inline unsigned int rfc2429_get_PLEN(const uint8_t *header){
-	unsigned short *p=(unsigned short*)header;
-	return (ntohs(p[0])>>3) & MAKE_MASK(6);
-}
-
 /*! \brief extract the bitstreem from the RTP payload.
  * This is format dependent.
  * For h263+, the format is defined in RFC 2429
@@ -546,26 +529,24 @@
 static int h263p_decap(struct fbuf_t *b, uint8_t *data, int len)
 {
 	int PLEN;
-	int P;
 
 	if (len < 2) {
 		ast_log(LOG_WARNING, "invalid framesize %d\n", len);
 		return 1;
 	}
-	PLEN = rfc2429_get_PLEN(data);
-	P = rfc2429_get_P(data);
+	PLEN = ( (data[0] & 1) << 5 ) | ( (data[1] & 0xf8) >> 3);
 
 	if (PLEN > 0) {
 		data += PLEN;
 		len -= PLEN;
 	}
-	if (P)
+	if (data[0] & 4)	/* bit P */
 		data[0] = data[1] = 0;
 	else {
 		data += 2;
 		len -= 2;
 	}
-	return fbuf_append(b, data, len, 0, 0);	/* XXX no bit alignment support */
+	return fbuf_append(b, data, len, 0, 0);	/* ignore trail bits */
 }
 
 /*
@@ -843,15 +824,14 @@
 
 	bzero(h261_hdr, sizeof(h261_hdr));
 
-	/* This is the same code we have in h263, but the maker there is longer.
-	 * We start a few bytes within the bitstream to avoid hitting the marker
-	 * twice. We stop at len-1 because when there are bits to ignore we move
-	 * back the 'start' pointer by 1, and this would cause us to enter the loop
-	 * one more time.
+	/* Similar to the code in h263_encap, but the marker there is longer.
+	 * Start a few bytes within the bitstream to avoid hitting the marker
+	 * twice. Stop at len-1 because when there are bits to ignore we move
+	 * back the 'start' pointer by 1, and this would cause us to enter
+	 * the loop one more time.
 	 */
 	for (i = H261_MIN_LEN, start = 0; start < len - 1; start = i, i += 4) {
 		int found = 0, found_ebit = 0;	/* last GBSC position found */
-		// ast_log(LOG_WARNING, "search at %d of %d/%d\n", i, start, len);
 		for (; i < len ; i++) {
 			uint8_t x, rpos, lpos;
 			if (d[i] != 0)		/* cannot be in a GBSC */
@@ -861,7 +841,7 @@
 			x = d[i+1];
 			if (x == 0)	/* next is equally good */
 				continue;
-			/* see if around us we can make 15 '0' bits for the GBSC.
+			/* See if around us we find 15 '0' bits for the GBSC.
 			 * Look for the first bit set on the right, and then
 			 * see if we have enough 0 on the left.
 			 * We are guaranteed to end before rpos == 0
@@ -878,7 +858,7 @@
 			/* now we have a GBSC starting somewhere in d[i-1],
 			 * but it might be not byte-aligned. Just remember it.
 			 */
-			if (i - start > out->mtu)	/* too large, stop now */
+			if (i - start > out->mtu) /* too large, stop now */
 				break;
 			found_ebit = ebit;
 			found = i;
@@ -888,7 +868,8 @@
 			i = len;
 			ebit = 0;	/* hopefully... should ask the bitstream ? */
 		}
-		if (i - start > out->mtu && found) {	/* hope the previous one is still ok */
+		if (i - start > out->mtu && found) {
+			/* use the previous GBSC, hope is within the mtu */
 			i = found;
 			ebit = found_ebit;
 		}
@@ -903,7 +884,7 @@
 		/* recompute header with I=0, V=1 */
 		h[0] = ( (sbit & 7) << 5 ) | ( (ebit & 7) << 2 ) | 1;
 		bcopy(h, f->data, 4);	/* copy the h261 header */
-		if (ebit) {	/* not aligned, so restart from previous byte */
+		if (ebit) {	/* not aligned, restart from previous byte */
 			sbit = 8 - ebit;
 			ebit = 0;
 			i--;
@@ -1609,10 +1590,8 @@
 	}
 
 #if defined(DROP_PACKETS) && DROP_PACKETS > 0
-	/*
-	 * Fragment of code to simulate lost/delayed packets
-	 */
-	if((random() % 10000) <= 100*DROP_PACKETS) {
+	/* Simulate lost/delayed packets */
+	if ((random() % 10000) <= 100*DROP_PACKETS) {
 		ast_log(LOG_NOTICE, "Packet lost [%d]\n", f->seqno);
 		return 0;
 	}