Typo: Remove space in 'centiseconds', 'microseconds', and 'nanoseconds'.

According to Chapter 3, Paragraph 2 of the "SI Brochure - 9th ed./version 3.02":

> Prefix symbols are printed in upright typeface, as are unit symbols,
> regardless of the typeface used in the surrounding text and are
> attached to unit symbols without a space between the prefix symbol
> and the unit symbol.

https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf

doc/developer.texi

@@ -387,7 +387,7 @@ symbols. If in doubt, just avoid names starting with @code{_} altogether.
 Casts should be used only when necessary. Unneeded parentheses
 should also be avoided if they don't make the code easier to understand.
 @item
-Where applicable, SI units shall be used. For example timeouts should use seconds as the fundamental unit not micro seconds.
+Where applicable, SI units shall be used. For example timeouts should use seconds as the fundamental unit not microseconds.
 That means a bare value like @samp{1.0} must mean 1 second, @samp{50m} means 50 milliseconds. For weight, gram shall be used.
 @end itemize
 

doc/muxers.texi

@@ -1759,7 +1759,7 @@ See also the @ref{framehash} and @ref{md5} muxers.
 Animated GIF muxer.
 
 Note that the GIF format has a very large time base: the delay between two frames can
-therefore not be smaller than one centi second.
+therefore not be smaller than one centisecond.
 
 @subsection Options
 @table @option

libavfilter/setpts.c

@@ -54,8 +54,8 @@ static const char *const var_names[] = {
     "STARTT",      ///< time at start of movie
     "T",           ///< original time in the file of the frame
     "TB",          ///< timebase
-    "RTCTIME",     ///< wallclock (RTC) time in micro seconds
-    "RTCSTART",    ///< wallclock (RTC) time at the start of the movie in micro seconds
+    "RTCTIME",     ///< wallclock (RTC) time in microseconds
+    "RTCSTART",    ///< wallclock (RTC) time at the start of the movie in microseconds
     "S",           //   Number of samples in the current frame
     "SR",          //   Audio sample rate
     "FR",          ///< defined only for constant frame-rate video

libavformat/img2dec.c

@@ -602,7 +602,7 @@ const AVOption ff_img_options[] = {
     { "ts_from_file", "set frame timestamp from file's one", OFFSET(ts_from_file), AV_OPT_TYPE_INT,    {.i64 = 0   }, 0, 2,       DEC, .unit = "ts_type" },
     { "none", "none",                   0, AV_OPT_TYPE_CONST,    {.i64 = 0   }, 0, 2,       DEC, .unit = "ts_type" },
     { "sec",  "second precision",       0, AV_OPT_TYPE_CONST,    {.i64 = 1   }, 0, 2,       DEC, .unit = "ts_type" },
-    { "ns",   "nano second precision",  0, AV_OPT_TYPE_CONST,    {.i64 = 2   }, 0, 2,       DEC, .unit = "ts_type" },
+    { "ns",   "nanosecond precision",   0, AV_OPT_TYPE_CONST,    {.i64 = 2   }, 0, 2,       DEC, .unit = "ts_type" },
     { "export_path_metadata", "enable metadata containing input path information", OFFSET(export_path_metadata), AV_OPT_TYPE_BOOL,   {.i64 = 0   }, 0, 1,       DEC }, \
     COMMON_OPTIONS
 };

libavformat/internal.h

@@ -424,16 +424,16 @@ uint64_t ff_ntp_time(void);
 /**
  * Get the NTP time stamp formatted as per the RFC-5905.
  *
- * @param ntp_time NTP time in micro seconds (since NTP epoch)
+ * @param ntp_time NTP time in microseconds (since NTP epoch)
  * @return the formatted NTP time stamp
  */
 uint64_t ff_get_formatted_ntp_time(uint64_t ntp_time_us);
 
 /**
- * Parse the NTP time in micro seconds (since NTP epoch).
+ * Parse the NTP time in microseconds (since NTP epoch).
  *
  * @param ntp_ts NTP time stamp formatted as per the RFC-5905.
- * @return the time in micro seconds (since NTP epoch)
+ * @return the time in microseconds (since NTP epoch)
  */
 uint64_t ff_parse_ntp_time(uint64_t ntp_ts);
 

libavformat/utils.c

@@ -264,7 +264,7 @@ uint64_t ff_get_formatted_ntp_time(uint64_t ntp_time_us)
     uint64_t ntp_ts, frac_part, sec;
     uint32_t usec;
 
-    //current ntp time in seconds and micro seconds
+    //current ntp time in seconds and microseconds
     sec = ntp_time_us / 1000000;
     usec = ntp_time_us % 1000000;