doc: Consistently use 'frame rate' everywhere

We used to use 'framerate' or 'frame rate' randomly.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

doc/demuxers.texi

@@ -120,7 +120,7 @@ same for all the files in the sequence.
 This demuxer accepts the following options:
 @table @option
 @item framerate
-Set the framerate for the video stream. It defaults to 25.
+Set the frame rate for the video stream. It defaults to 25.
 @item loop
 If set to 1, loop over the input. Default value is 0.
 @item pattern_type

doc/ffmpeg-codecs.texi

@@ -144,8 +144,8 @@ Set codec time base.
 
 It is the fundamental unit of time (in seconds) in terms of which
 frame timestamps are represented. For fixed-fps content, timebase
-should be 1/framerate and timestamp increments should be identically
-1.
+should be @code{1 / frame_rate} and timestamp increments should be
+identically 1.
 
 @item g @var{integer} (@emph{encoding,video})
 Set the group of picture size. Default value is 12.

doc/ffmpeg.texi

@@ -896,7 +896,7 @@ Newly added values will have to be specified as strings always.
 Each frame is passed with its timestamp from the demuxer to the muxer.
 @item 1, cfr
 Frames will be duplicated and dropped to achieve exactly the requested
-constant framerate.
+constant frame rate.
 @item 2, vfr
 Frames are passed through with their timestamp or dropped so as to
 prevent 2 frames from having the same timestamp.

doc/filter_design.txt

@@ -204,7 +204,7 @@ Frame scheduling
     filter; these buffered frames must be flushed immediately if a new input
     produces new output.
 
-    (Example: framerate-doubling filter: filter_frame must (1) flush the
+    (Example: frame rate-doubling filter: filter_frame must (1) flush the
     second copy of the previous frame, if it is still there, (2) push the
     first copy of the incoming frame, (3) keep the second copy for later.)
 

doc/filters.texi

@@ -2404,7 +2404,7 @@ curves=vintage
 @section decimate
 
 Drop frames that do not differ greatly from the previous frame in
-order to reduce framerate.
+order to reduce frame rate.
 
 The main use of this filter is for very-low-bitrate encoding
 (e.g. streaming over dialup modem), but it could in theory be used for
@@ -3169,14 +3169,14 @@ format=yuv420p:yuv444p:yuv410p
 
 @section fps
 
-Convert the video to specified constant framerate by duplicating or dropping
+Convert the video to specified constant frame rate by duplicating or dropping
 frames as necessary.
 
 This filter accepts the following named parameters:
 @table @option
 
 @item fps
-Desired output framerate. The default is @code{25}.
+Desired output frame rate. The default is @code{25}.
 
 @item round
 Rounding method.
@@ -5387,27 +5387,27 @@ Available values are:
 @table @samp
 @item merge, 0
 Move odd frames into the upper field, even into the lower field,
-generating a double height frame at half framerate.
+generating a double height frame at half frame rate.
 
 @item drop_odd, 1
 Only output even frames, odd frames are dropped, generating a frame with
-unchanged height at half framerate.
+unchanged height at half frame rate.
 
 @item drop_even, 2
 Only output odd frames, even frames are dropped, generating a frame with
-unchanged height at half framerate.
+unchanged height at half frame rate.
 
 @item pad, 3
 Expand each frame to full height, but pad alternate lines with black,
-generating a frame with double height at the same input framerate.
+generating a frame with double height at the same input frame rate.
 
 @item interleave_top, 4
 Interleave the upper field from odd frames with the lower field from
-even frames, generating a frame with unchanged height at half framerate.
+even frames, generating a frame with unchanged height at half frame rate.
 
 @item interleave_bottom, 5
 Interleave the lower field from odd frames with the upper field from
-even frames, generating a frame with unchanged height at half framerate.
+even frames, generating a frame with unchanged height at half frame rate.
 
 @item interlacex2, 6
 Double frame rate with unchanged height. Frames are inserted each
@@ -7003,7 +7003,7 @@ amovie=a.mp3,asplit[out0],showwaves[out1]
 
 @item
 Create a synthetic signal and show it with showwaves, forcing a
-framerate of 30 frames per second:
+frame rate of 30 frames per second:
 @example
 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
 @end example

doc/indevs.texi

@@ -86,7 +86,7 @@ fail to open.
 Set the video size in the captured video.
 
 @item framerate
-Set the framerate in the captured video.
+Set the frame rate in the captured video.
 
 @item sample_rate
 Set the sample rate (in Hz) of the captured audio.
@@ -600,7 +600,7 @@ kind @file{/dev/video@var{N}}, where @var{N} is a number associated to
 the device.
 
 Video4Linux2 devices usually support a limited set of
-@var{width}x@var{height} sizes and framerates. You can check which are
+@var{width}x@var{height} sizes and frame rates. You can check which are
 supported using @command{-list_formats all} for Video4Linux2 devices.
 Some devices, like TV cards, support one or more standards. It is possible
 to list all the supported standards using @command{-list_standards all}.
@@ -623,7 +623,7 @@ ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
 
 @item
 Grab and record the input of a video4linux2 device, leave the
-framerate and size as previously set:
+frame rate and size as previously set:
 @example
 ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
 @end example
@@ -656,7 +656,7 @@ This option allows to select the input format, when several are
 available.
 
 @item framerate
-Set the preferred video framerate.
+Set the preferred video frame rate.
 
 @item list_formats
 List available formats (supported pixel formats, codecs, and frame
@@ -772,7 +772,7 @@ ffmpeg -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg
 
 @item framerate
 Set the grabbing frame rate. Default value is @code{ntsc},
-corresponding to a framerate of @code{30000/1001}.
+corresponding to a frame rate of @code{30000/1001}.
 
 @item show_region
 Show grabbed region on screen.