avformat: add av_stream_get_codec_timebase()

This will allow ffmpeg.c to stop using AVStream.codec in some cases
Signed-off-by: James Almer <jamrial@gmail.com>

doc/APIchanges

@@ -15,6 +15,9 @@ libavutil:     2015-08-28
 
 API changes, most recent first:
 
+2016-09-27 - xxxxxxx - lavf 57.51.100 - avformat.h
+  Add av_stream_get_codec_timebase()
+
 2016-09-27 - 23c0779 - lswr 2.2.100 - swresample.h
   Add swr_build_matrix().
 

libavformat/avformat.h

@@ -2921,6 +2921,13 @@ int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
                                                   AVStream *ost, const AVStream *ist,
                                                   enum AVTimebaseSource copy_tb);
 
+/**
+ * Get the internal codec timebase from a stream.
+ *
+ * @param st  input stream to extract the timebase from
+ */
+AVRational av_stream_get_codec_timebase(const AVStream *st);
+
 /**
  * @}
  */

libavformat/utils.c

@@ -5383,3 +5383,15 @@ int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
 
     return 0;
 }
+
+AVRational av_stream_get_codec_timebase(const AVStream *st)
+{
+    // See avformat_transfer_internal_stream_timing_info() TODO.
+#if FF_API_LAVF_AVCTX
+FF_DISABLE_DEPRECATION_WARNINGS
+    return st->codec->time_base;
+FF_ENABLE_DEPRECATION_WARNINGS
+#else
+    return st->internal->avctx->time_base;
+#endif
+}

libavformat/version.h

@@ -32,7 +32,7 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  57
-#define LIBAVFORMAT_VERSION_MINOR  50
+#define LIBAVFORMAT_VERSION_MINOR  51
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \