Add a comment about swapped numerator and denominator.

Originally committed as revision 7871 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/libtheoraenc.c b/libavcodec/libtheoraenc.c
index 3fc70cf3841e16b4c6634365b225c4c09d720b2c..7f531dbee546805f699f4299db4447c9801e6f2e 100644 (file)
--- a/libavcodec/libtheoraenc.c
+++ b/libavcodec/libtheoraenc.c
@@ -92,6 +92,8 @@ static int encode_init(AVCodecContext* avc_context)
     t_info.frame_height = avc_context->height;
     t_info.offset_x = 0;
     t_info.offset_y = 0;
+    /* Swap numerator and denominator as time_base in AVCodecContext gives the
+     * time period between frames, but theora_info needs the framerate.  */
     t_info.fps_numerator = avc_context->time_base.den;
     t_info.fps_denominator = avc_context->time_base.num;
     if (avc_context->sample_aspect_ratio.num != 0) {