Fix precission typos

Found-by: ubitux
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

ffmpeg.c

@@ -1241,7 +1241,7 @@ static int reap_filters(void)
         filtered_frame = ost->filtered_frame;
 
         while (1) {
-            double float_pts = AV_NOPTS_VALUE; // this is identical to filtered_frame.pts but with higher precission
+            double float_pts = AV_NOPTS_VALUE; // this is identical to filtered_frame.pts but with higher precision
             ret = av_buffersink_get_frame_flags(filter, filtered_frame,
                                                AV_BUFFERSINK_FLAG_NO_REQUEST);
             if (ret < 0) {

libavcodec/mpegvideo_enc.c

@@ -342,7 +342,7 @@ av_cold int ff_mpv_encode_init(AVCodecContext *avctx)
     s->rtp_mode           = !!avctx->rtp_payload_size;
     s->intra_dc_precision = avctx->intra_dc_precision;
 
-    // workaround some differences between how applications specify dc precission
+    // workaround some differences between how applications specify dc precision
     if (s->intra_dc_precision < 0) {
         s->intra_dc_precision += 8;
     } else if (s->intra_dc_precision >= 8)