avcodec: correct framerate calculation

VLC frequently reports a framerate that is twice the actual framerate for interlaced content.
Correctly take the information from ffmpeg in account when determining the framerate. It now
correctly reports the actual framerate of the movie.

modules/codec/avcodec/video.c

@@ -98,7 +98,6 @@ struct decoder_sys_t
     /* Hack to force display of still pictures */
     bool b_first_frame;
 
-
     /* */
 #if LIBAVCODEC_VERSION_MAJOR < 54
     AVPaletteControl palette;
@@ -198,8 +197,14 @@ static inline picture_t *ffmpeg_NewPictBuf( decoder_t *p_dec,
     }
     else if( p_context->time_base.num > 0 && p_context->time_base.den > 0 )
     {
-        p_dec->fmt_out.video.i_frame_rate = p_context->time_base.den;
-        p_dec->fmt_out.video.i_frame_rate_base = p_context->time_base.num;
+        p_dec->fmt_out.video.i_frame_rate = p_context->time_base.num *
+                                                __MAX( p_context->ticks_per_frame, 1 );
+        p_dec->fmt_out.video.i_frame_rate_base = p_context->time_base.den;
+
+        vlc_ureduce(&p_dec->fmt_out.video.i_frame_rate,
+                    &p_dec->fmt_out.video.i_frame_rate_base,
+                    p_dec->fmt_out.video.i_frame_rate,
+                    p_dec->fmt_out.video.i_frame_rate_base, 0);
     }
 
     return decoder_NewPicture( p_dec );
@@ -400,7 +405,6 @@ int InitVideoDec( decoder_t *p_dec, AVCodecContext *p_context,
         p_dec->i_extra_picture_buffers = 2 * p_sys->p_context->thread_count;
 #endif
 
-
     /* ***** misc init ***** */
     p_sys->i_pts = VLC_TS_INVALID;
     p_sys->b_has_b_frames = false;
@@ -704,6 +708,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
                 i_pts = i_ts;
             }
         }
+
         if( i_pts <= VLC_TS_INVALID )
             i_pts = p_sys->i_pts;
 
@@ -713,15 +718,16 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
         if( p_sys->i_pts > VLC_TS_INVALID )
         {
             /* interpolate the next PTS */
-            if( p_dec->fmt_in.video.i_frame_rate > 0 &&
-                p_dec->fmt_in.video.i_frame_rate_base > 0 )
+            if( p_dec->fmt_out.video.i_frame_rate > 0 &&
+                p_dec->fmt_out.video.i_frame_rate_base > 0 )
             {
                 p_sys->i_pts += INT64_C(1000000) *
                     (2 + p_sys->p_ff_pic->repeat_pict) *
-                    p_dec->fmt_in.video.i_frame_rate_base /
-                    (2 * p_dec->fmt_in.video.i_frame_rate);
+                    p_dec->fmt_out.video.i_frame_rate /
+                    (2 * p_dec->fmt_out.video.i_frame_rate_base);
             }
-            else if( p_context->time_base.den > 0 )
+            else if( p_context->time_base.num > 0 &&
+                     p_context->time_base.den > 0 )
             {
                 int i_tick = p_context->ticks_per_frame;
                 if( i_tick <= 0 )
@@ -729,7 +735,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
 
                 p_sys->i_pts += INT64_C(1000000) *
                     (2 + p_sys->p_ff_pic->repeat_pict) *
-                    i_tick * p_context->time_base.num /
+                    (i_tick * p_context->time_base.num) /
                     (2 * p_context->time_base.den);
             }
         }
@@ -833,7 +839,6 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
                     break;
                 }
             }
-
             return p_pic;
         }
         else
@@ -1266,4 +1271,3 @@ static enum PixelFormat ffmpeg_GetFormat( AVCodecContext *p_context,
     return avcodec_default_get_format( p_context, pi_fmt );
 }
 #endif
-