[FFmpeg-devel] [PATCH] rmdec.c: correctly skip indexes

[Ronald S. Bultje]

Hi,

On Mon, Mar 9, 2009 at 1:24 PM, Kostya <kostya.shishkov at gmail.com> wrote:
> if header_size == 0x14 and num_indices > 0 then calculate real size (and skip)
> otherwise check header_size value to be 0x14+num_indices*0xE and throw
> a warning if it is not (and skip that size anyway).

OK, see attached. Is the 0x14 vs. 14 thing annoying/confusing?

Ronald
-------------- next part --------------
Index: ffmpeg-svn/libavformat/rmdec.c
===================================================================
--- ffmpeg-svn.orig/libavformat/rmdec.c	2009-03-09 09:45:42.000000000 -0400
+++ ffmpeg-svn/libavformat/rmdec.c	2009-03-09 12:35:31.000000000 -0400
@@ -440,7 +440,20 @@
             state= (state<<8) + get_byte(pb);
 
             if(state == MKBETAG('I', 'N', 'D', 'X')){
-                len = get_be16(pb) - 6;
+                int size, n_pkts;
+                size = get_be32(pb);
+                url_fskip(pb, 2);
+                n_pkts = get_be32(pb);
+                if (size == 0x14) {
+                    /* some files don't add index entries to total size... */
+                    len = size - 14 + n_pkts * 14;
+                } else {
+                    len = size - 14;
+                    if (size - 0x14 != n_pkts * 14)
+                        av_log(s, AV_LOG_WARNING,
+                               "Index size %d (%d pkts) looks broken.\n",
+                               size, n_pkts);
+                }
                 if(len<0)
                     continue;
                 goto skip;