From d80f0a4ad634b3949b91b85f21fd608c0cddeef7 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Wed, 18 Nov 2015 10:32:34 +0100
Subject: [PATCH] mpevideo_enc: disallow multiple slices for h261 and flv

They do not work and produce corrupted output.

CC: libav-stable@libav.org
---
 libavcodec/mpegvideo_enc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
index ab4fb32bed..d572b859a0 100644
--- a/libavcodec/mpegvideo_enc.c
+++ b/libavcodec/mpegvideo_enc.c
@@ -496,6 +496,12 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
     }
 
+    if (avctx->slices > 1 &&
+        (avctx->codec_id == AV_CODEC_ID_FLV1 || avctx->codec_id == AV_CODEC_ID_H261)) {
+        av_log(avctx, AV_LOG_ERROR, "Multiple slices are not supported by this codec\n");
+        return AVERROR(EINVAL);
+    }
+
     if (s->avctx->thread_count > 1         &&
         s->codec_id != AV_CODEC_ID_MPEG4      &&
         s->codec_id != AV_CODEC_ID_MPEG1VIDEO &&