[FFmpeg-cvslog] wavpack: skip blocks with no samples

[Kostya Shishkov]

ffmpeg | branch: master | Kostya Shishkov <kostya.shishkov at gmail.com> | Tue Jun 28 11:49:32 2011 +0200| [cb7b55b0962f5503f601d6b557f8945444b73395] | committer: Mans Rullgard

wavpack: skip blocks with no samples

These blocks don't report audio stream parameters and they are not needed
for decoding.

Signed-off-by: Mans Rullgard <mans at mansr.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cb7b55b0962f5503f601d6b557f8945444b73395
---

 libavformat/wv.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/libavformat/wv.c b/libavformat/wv.c
index 8f9d0fd..d6d7099 100644
--- a/libavformat/wv.c
+++ b/libavformat/wv.c
@@ -110,6 +110,9 @@ static int wv_read_block_header(AVFormatContext *ctx, AVIOContext *pb, int appen
         size = wc->blksize;
     }
     wc->flags = AV_RL32(wc->extra + 4);
+    // blocks with zero samples don't contain actual audio information and should be ignored
+    if (!AV_RN32(wc->extra))
+        return 0;
     //parse flags
     bpp = ((wc->flags & 3) + 1) << 3;
     chan = 1 + !(wc->flags & WV_MONO);
@@ -207,8 +210,14 @@ static int wv_read_header(AVFormatContext *s,
     AVStream *st;
 
     wc->block_parsed = 0;
-    if(wv_read_block_header(s, pb, 0) < 0)
-        return -1;
+    for(;;){
+        if(wv_read_block_header(s, pb, 0) < 0)
+            return -1;
+        if(!AV_RN32(wc->extra))
+            avio_skip(pb, wc->blksize - 24);
+        else
+            break;
+    }
 
     /* now we are ready: build format streams */
     st = av_new_stream(s, 0);