[FFmpeg-cvslog] doc/examples/transcoding: check encoder before using it

[Michael Niedermayer]

ffmpeg | branch: release/2.4 | Michael Niedermayer <michaelni at gmx.at> | Thu Dec  4 18:58:38 2014 +0100| [fd72ff6f31f9626e1e871079cf4f2259b26f1a27] | committer: Michael Niedermayer

doc/examples/transcoding: check encoder before using it

Fixes null pointer exception

Found-by: stoupeace
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit bde27e1e617dfeb3c026f530f48a77f5ed8aa2ea)

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fd72ff6f31f9626e1e871079cf4f2259b26f1a27
---

 doc/examples/transcoding.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/doc/examples/transcoding.c b/doc/examples/transcoding.c
index a8f4210..d7c4a84 100644
--- a/doc/examples/transcoding.c
+++ b/doc/examples/transcoding.c
@@ -116,6 +116,10 @@ static int open_output_file(const char *filename)
                 || dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
             /* in this example, we choose transcoding to same codec */
             encoder = avcodec_find_encoder(dec_ctx->codec_id);
+            if (!encoder) {
+                av_log(NULL, AV_LOG_FATAL, "Neccessary encoder not found\n");
+                return AVERROR_INVALIDDATA;
+            }
 
             /* In this example, we transcode to same properties (picture size,
              * sample rate etc.). These properties can be changed for output