[FFmpeg-cvslog] avcodec/h264: Put context_count check back

[Michael Niedermayer]

ffmpeg | branch: release/3.0 | Michael Niedermayer <michael at niedermayer.cc> | Wed Jun  8 12:32:57 2016 +0200| [66bd740e0ba5d43d58d12f79addaf9acf8e3c0ae] | committer: Michael Niedermayer

avcodec/h264: Put context_count check back

Fixes assertion failure

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit f883f0b0bd0dac76b58e49f5c75cf9b497eecaa0)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=66bd740e0ba5d43d58d12f79addaf9acf8e3c0ae
---

 libavcodec/h264.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index b1001f8..b979b15 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -1656,10 +1656,12 @@ again:
                     av_log(h->avctx, AV_LOG_ERROR, "decode_slice_header error\n");
                 sl->ref_count[0] = sl->ref_count[1] = sl->list_count = 0;
             } else if (err == SLICE_SINGLETHREAD) {
-                ret = ff_h264_execute_decode_slices(h, context_count);
-                if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
-                    goto end;
-                context_count = 0;
+                if (context_count > 0) {
+                    ret = ff_h264_execute_decode_slices(h, context_count);
+                    if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
+                        goto end;
+                    context_count = 0;
+                }
                 /* Slice could not be decoded in parallel mode, restart. Note
                  * that rbsp_buffer is not transferred, but since we no longer
                  * run in parallel mode this should not be an issue. */