avformat/options: Only allocate AVCodecContext for demuxers

The muxer's AVCodecContext is currently used for exactly one thing:
To store a time base in it that has been derived via heuristics
in avformat_transfer_internal_stream_timing_info(); said time base
can then be read back via av_stream_get_codec_timebase().
But one does not need a whole AVCodecContext for that, a simple
AVRational is enough.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/libavformat/dump.c b/libavformat/dump.c
index add38914f2..9d37179bb7 100644
--- a/libavformat/dump.c
+++ b/libavformat/dump.c
@@ -565,12 +565,14 @@ static void dump_stream_format(const AVFormatContext *ic, int i,
     }
 
     // Fields which are missing from AVCodecParameters need to be taken from the AVCodecContext
-    avctx->properties   = sti->avctx->properties;
-    avctx->codec        = sti->avctx->codec;
-    avctx->qmin         = sti->avctx->qmin;
-    avctx->qmax         = sti->avctx->qmax;
-    avctx->coded_width  = sti->avctx->coded_width;
-    avctx->coded_height = sti->avctx->coded_height;
+    if (sti->avctx) {
+        avctx->properties   = sti->avctx->properties;
+        avctx->codec        = sti->avctx->codec;
+        avctx->qmin         = sti->avctx->qmin;
+        avctx->qmax         = sti->avctx->qmax;
+        avctx->coded_width  = sti->avctx->coded_width;
+        avctx->coded_height = sti->avctx->coded_height;
+    }
 
     if (separator)
         av_opt_set(avctx, "dump_separator", separator, 0);