lavc/{av1, h264, h265}_metadata_bsf: fix description of tick_rate

Users may take the description literally which leads to inverted
results.

Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
Reviewed-by: Jun Zhao <barryjzhao@tencent.com

doc/bitstream_filters.texi

@@ -81,7 +81,7 @@ Top-left position.
 @end table
 
 @item tick_rate
-Set the tick rate (@emph{num_units_in_display_tick / time_scale}) in
+Set the tick rate (@emph{time_scale / num_units_in_display_tick}) in
 the timing info in the sequence header.
 @item num_ticks_per_picture
 Set the number of ticks in each picture, to indicate that the stream
@@ -244,7 +244,7 @@ Set the chroma sample location in the stream (see H.264 section
 E.2.1 and figure E-1).
 
 @item tick_rate
-Set the tick rate (num_units_in_tick / time_scale) in the VUI
+Set the tick rate (time_scale / num_units_in_tick) in the VUI
 parameters.  This is the smallest time unit representable in the
 stream, and in many cases represents the field rate of the stream
 (double the frame rate).
@@ -352,8 +352,8 @@ Set the chroma sample location in the stream (see H.265 section
 E.3.1 and figure E.1).
 
 @item tick_rate
-Set the tick rate in the VPS and VUI parameters (num_units_in_tick /
+Set the tick rate in the VPS and VUI parameters (time_scale /
-time_scale).  Combined with @option{num_ticks_poc_diff_one}, this can
+num_units_in_tick). Combined with @option{num_ticks_poc_diff_one}, this can
 set a constant framerate in the stream.  Note that it is likely to be
 overridden by container parameters when the stream is in a container.
 

libavcodec/av1_metadata_bsf.c

@@ -194,7 +194,7 @@ static const AVOption av1_metadata_options[] = {
     { "colocated", "Top-left chroma sample position", 0, AV_OPT_TYPE_CONST,
         { .i64 = AV1_CSP_COLOCATED }, .flags = FLAGS, .unit = "csp" },
 
-    { "tick_rate", "Set display tick rate (num_units_in_display_tick / time_scale)",
+    { "tick_rate", "Set display tick rate (time_scale / num_units_in_display_tick)",
         OFFSET(tick_rate), AV_OPT_TYPE_RATIONAL,
         { .dbl = 0.0 }, 0, UINT_MAX, FLAGS },
     { "num_ticks_per_picture", "Set display ticks per picture for CFR streams",

libavcodec/h264_metadata_bsf.c

@@ -626,7 +626,7 @@ static const AVOption h264_metadata_options[] = {
         OFFSET(chroma_sample_loc_type), AV_OPT_TYPE_INT,
         { .i64 = -1 }, -1, 6, FLAGS },
 
-    { "tick_rate", "Set VUI tick rate (num_units_in_tick / time_scale)",
+    { "tick_rate", "Set VUI tick rate (time_scale / num_units_in_tick)",
         OFFSET(tick_rate), AV_OPT_TYPE_RATIONAL,
         { .dbl = 0.0 }, 0, UINT_MAX, FLAGS },
     { "fixed_frame_rate_flag", "Set VUI fixed frame rate flag",

libavcodec/h265_metadata_bsf.c

@@ -439,7 +439,7 @@ static const AVOption h265_metadata_options[] = {
         { .i64 = -1 }, -1, 6, FLAGS },
 
     { "tick_rate",
-        "Set VPS and VUI tick rate (num_units_in_tick / time_scale)",
+        "Set VPS and VUI tick rate (time_scale / num_units_in_tick)",
         OFFSET(tick_rate), AV_OPT_TYPE_RATIONAL,
         { .dbl = 0.0 }, 0, UINT_MAX, FLAGS },
     { "num_ticks_poc_diff_one",