Backport [18549] and extend it.

I am very suspicious about the original commit to trunk by the way
(Why is signed int wrong in one place and right in the others?
 Could be, but really looks unlikely to me)

modules/codec/ffmpeg/encoder.c

@@ -791,9 +791,9 @@ static block_t *EncodeVideo( encoder_t *p_enc, picture_t *p_pict )
     if( 1 )
 #endif
     {
-        frame.pts = p_pict->date ? p_pict->date : (signed int) AV_NOPTS_VALUE;
+        frame.pts = p_pict->date ? p_pict->date : AV_NOPTS_VALUE;
 
-        if ( p_sys->b_hurry_up && frame.pts != (signed int) AV_NOPTS_VALUE )
+        if ( p_sys->b_hurry_up && frame.pts != AV_NOPTS_VALUE )
         {
             mtime_t current_date = mdate();
 
@@ -839,7 +839,7 @@ static block_t *EncodeVideo( encoder_t *p_enc, picture_t *p_pict )
         frame.pts = AV_NOPTS_VALUE;
     }
 
-    if ( frame.pts != (signed int) AV_NOPTS_VALUE && frame.pts != 0 )
+    if ( frame.pts != AV_NOPTS_VALUE && frame.pts != 0 )
     {
         if ( p_sys->i_last_pts == frame.pts )
         {
@@ -891,7 +891,7 @@ static block_t *EncodeVideo( encoder_t *p_enc, picture_t *p_pict )
             /* No delay -> output pts == input pts */
             p_block->i_pts = p_block->i_dts = p_pict->date;
         }
-        else if( p_sys->p_context->coded_frame->pts != (signed int) AV_NOPTS_VALUE &&
+        else if( p_sys->p_context->coded_frame->pts != AV_NOPTS_VALUE &&
             p_sys->p_context->coded_frame->pts != 0 &&
             p_sys->i_buggy_pts_detect != p_sys->p_context->coded_frame->pts )
         {