From 8f6b919d99687416deaedb2df6b8b5f49645a291 Mon Sep 17 00:00:00 2001
From: Carl Eugen Hoyos <cehoyos@ag.or.at>
Date: Thu, 21 May 2015 00:43:38 +0200
Subject: [PATCH] lavf/mkv: Only skip prores header if the packet is large
 enough.

Fixes a possible endless loop.
---
 libavformat/matroskaenc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 7cbba0b002..c4c58f4d09 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -1575,7 +1575,7 @@ static void mkv_write_block(AVFormatContext *s, AVIOContext *pb,
     } else
         data = pkt->data;
 
-    if (codec->codec_id == AV_CODEC_ID_PRORES) {
+    if (codec->codec_id == AV_CODEC_ID_PRORES && size >= 8) {
         /* Matroska specification requires to remove the first QuickTime atom
          */
         size  -= 8;