From 7e4709b18ffe5debefd8127a40f23594e4b86047 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Wed, 17 Jan 2007 10:44:57 +0000
Subject: [PATCH] reduce len checks, simplifies code there is a very small
 chance that a stream which is damaged && unseekable && very small packet &&
 damage to the flags && unlucky buffer state could have a valid packet after a
 damaged packet lost, but i think this is so unlikely that the simplification
 outweights it mans if you disagree with any commit to mpeg.c just say so and
 ill revert it

Originally committed as revision 7562 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavformat/mpeg.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/libavformat/mpeg.c b/libavformat/mpeg.c
index 932557e673..147bce5968 100644
--- a/libavformat/mpeg.c
+++ b/libavformat/mpeg.c
@@ -1498,20 +1498,14 @@ static int mpegps_read_pes_header(AVFormatContext *s,
     }
     if ((c & 0xc0) == 0x40) {
         /* buffer scale & size */
-        if (len < 2)
-            goto error_redo;
         get_byte(&s->pb);
         c = get_byte(&s->pb);
         len -= 2;
     }
     if ((c & 0xf0) == 0x20) {
-        if (len < 4)
-            goto error_redo;
         dts = pts = get_pts(&s->pb, c);
         len -= 4;
     } else if ((c & 0xf0) == 0x30) {
-        if (len < 9)
-            goto error_redo;
         pts = get_pts(&s->pb, c);
         dts = get_pts(&s->pb, -1);
         len -= 9;
@@ -1530,15 +1524,11 @@ static int mpegps_read_pes_header(AVFormatContext *s,
             goto error_redo;
         if ((flags & 0xc0) == 0x80) {
             dts = pts = get_pts(&s->pb, -1);
-            if (header_len < 5)
-                goto error_redo;
             header_len -= 5;
             len -= 5;
         } if ((flags & 0xc0) == 0xc0) {
             pts = get_pts(&s->pb, -1);
             dts = get_pts(&s->pb, -1);
-            if (header_len < 10)
-                goto error_redo;
             header_len -= 10;
             len -= 10;
         }
@@ -1552,20 +1542,18 @@ static int mpegps_read_pes_header(AVFormatContext *s,
         goto redo;
 
     if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
-        if (len < 1)
-            goto error_redo;
         startcode = get_byte(&s->pb);
         len--;
         if (startcode >= 0x80 && startcode <= 0xbf) {
             /* audio: skip header */
-            if (len < 3)
-                goto error_redo;
             get_byte(&s->pb);
             get_byte(&s->pb);
             get_byte(&s->pb);
             len -= 3;
         }
     }
+    if(len<0)
+        goto error_redo;
     if(dts != AV_NOPTS_VALUE && ppos){
         int i;
         for(i=0; i<s->nb_streams; i++){